VCE Chemistry Units 1 And 2: 2016–2020

VCE Chemistry Units 1 and 2: 2016–2020; Units 3 and 4: 2017–2021 ADVICE FOR TEACHERS VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS

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Contents VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS

Introduction

The VCE Chemistry Advice for teachers handbook provides curriculum and assessment advice for Units 1 to 4. It contains advice for developing a course with examples of teaching and learning activities and resources for each unit. Assessment information is provided for school-based assessment in Units 3 and 4 and advice for teachers on how to construct assessment tasks with suggested performance descriptors and rubrics. The course developed and delivered to students must be in accordance with the VCE Chemistry Study Design Units 1 and 2: 2016–2020; Units 3 and 4: 2017–2021.

Administration

Advice on matters related to the administration of Victorian Certificate of Education (VCE) assessment is published annually in the VCE and VCAL Administrative Handbook. Updates to matters related to the administration of VCE assessment are published in the VCAA Bulletin. Teachers must refer to these publications for current advice. VCE Chemistry study design examination specifications, past examination papers and corresponding examination reports can be accessed at: www.vcaa.vic.edu.au/Pages/vce/studies/chemistry/exams.aspx. Graded Distributions for Graded Assessment can be accessed at: www.vcaa.vic.edu.au/Pages/vce/statistics/2015/index.aspx.

Developing a program

Overview The program outlines the nature and sequence of teaching and learning necessary for students to demonstrate achievement of the set of outcomes for a unit. The areas of study describe the learning context, the knowledge and skills required for the demonstration of each outcome. Each outcome draws on the set of contextualised key skills for Chemistry listed on pages 10 and 11 of the study design. The development, use and application of the key science skills must be integrated into the teaching sequence. These skills support a number of pedagogical approaches to teaching and learning including a focus on inquiry where students pose questions, explore scientific ideas, draw evidence-based conclusions and propose solutions to problems. Teachers must develop programs that include appropriate learning activities to enable students to develop the knowledge and skills identified in the outcomes in each unit. Attention should be given to designing a course of study that is relevant to students, contextually based, employs a manageable number of wide ranging student tasks, and uses a variety of source material from a diverse number of providers. Learning activities must include investigative work that involves the generation of primary data, including laboratory work and/or fieldwork. This may involve the use of data logging and other technologies. Other learning activities may include investigations involving the generation of primary © VCAA 2016 5 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS and/or collection of secondary data through simulations, animations, literature reviews, examination of case studies and the use of local and global databases.

Scientific inquiry focus The opportunity for students to work scientifically and respond to questions is an important feature of the VCE Chemistry Study Design. Questions reflect the inquiry nature of studying science and can be framed to provide contexts for developing conceptual understanding. The VCE Chemistry Study Design is structured under a set of unit questions and area of study questions. These questions are open-ended to enable students to engage in critical and creative thinking about the chemistry concepts identified in the key knowledge and to encourage students to ask their own questions about what they are learning. In responding to these questions, students demonstrate their own conceptual links and the relevance of different concepts to practical applications. Students studying Units 1 to 4 in VCE Chemistry will undertake a range of investigations involving five main types of scientific inquiry based on the levels of student autonomy:

Type of inquiry Problem or Question Procedure Solution Confirmation/verificati Teacher Teacher Teacher on Structured Teacher Teacher Student Guided Teacher Student Student Coupled (linked to an Initial: Teacher Student Student earlier inquiry) Coupled: Student Open Student Student Student

Appendix 1 provides definitions of the five types of scientific inquiry Students may undertake scientific inquiry individually or as part of a group or class to complete an activity, but findings, analysis and conclusions should be reported individually. If optional assessment tasks are used to cater for different student interests, teachers must ensure that they are comparable in scope and demand. Teachers are advised to utilise the flexibility provided by the structure of the study design in the choice of contexts, both local and global, and applications for enabling students to develop skills and understanding. Opportunities range from the entire class studying a particular context or application chosen by the teacher or agreed to by the class, through to students nominating their own choice of issues, scenarios, research or case studies or fieldwork activities. Appendix 8 provides examples of the use of a problem-based learning approach to develop scientific skills and understanding.

Practical activities Practical activities may be used to introduce and consolidate understanding of a chemical concept and to develop scientific skills and should not be limited to assessment tasks.

The principles of fair testing through controlled experiments are important in science, but may not always enable students to understand scientific ideas or concepts, answer their questions or appreciate how scientists work and the nature of science. At this level, different methods of scientific inquiry that generate primary data may be utilised. Common to different methods of scientific inquiry and practical activities are three key aspects that are central to the study design’s inquiry focus: asking questions, testing ideas and using evidence. © VCAA 2016 6 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS The following table identifies examples of practical activities involving a range of scientific inquiry methods across VCE Chemistry Units 1 to 4 that enable development of scientific skills:

Unit Examples of practical activities that develop scientific skills 1  Controlled experiment: investigate how temperature affects the rate of crystal growth  Single variable exploration: use a stereomicroscope to investigate how crystal growth changes over time  Pattern seeking: investigate the factors that affect the corrosion of an iron nail  Product, process or system development : formulate a biodegradable ink for use with recyclable paper 2  Controlled experiment: investigate how the solubility of ionic compounds vary with temperature  Classification and identification: identify a group of unknown salts  Product, process or system development: design a regime for the rapid comparison of the total amount of dissolved solids in different water samples 3  Product, process or system development: design apparatus or a technique for measuring and comparing the viscosities of liquid fuels  Product, process or system development: design, construct and test a small- scale biogas generator  Single variable exploration: investigate how the voltage across a copper-zinc galvanic cell changes over time  Pattern seeking: investigate the factors that affect the amount of metal deposited at a cathode in the electrolysis of ionic compounds 4  Controlled experiment: investigate the effect of pH on enzyme activity  Product, process or system development: design, construct, test and modify a polarimeter to study chirality in glucose molecules  Investigation of scientific models: devise and test a model of the relationship between the structures of different triglycerides and their melting points  Single variable exploration: investigate when the vitamin C content of a fruit is at its peak Appendix 2 provides more information about, and examples of, different scientific inquiry methods.

Fieldwork The study of VCE Chemistry may require fieldwork or site tours. If using local, state or national parks for fieldwork, regulations regarding activities and the collection of samples should be checked and followed. Activities should be planned to create minimal impact on the environment under investigation. Alternatives to the collection of biotic and abiotic materials, for example scientific drawings, photography, digital imaging and video capture, should be considered by schools. Industrial sites, water and sewage treatment plants, research and development laboratories and chemistry laboratories will have special safety warnings and requirements that must be strictly followed, including that students wear the appropriate clothing and footwear.

© VCAA 2016 7 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS The undertaking of fieldwork will be affected by availability of resources, physical conditions and accessibility of local ecosystems and weather conditions. It is important to consider these factors when sequencing learning activities.

Student safety and wellbeing When developing courses, some issues to consider include: duty of care in relation to health and safety of students in learning activities, practical work and excursions; legislative compliance (for example, chemical handling and storage, information privacy and copyright); sensitivity to cultural differences and personal beliefs (for example, in discussions related to health and environmental issues); adherence to community standards and ethical guidelines (for example, respecting the confidentiality of industrial processes and data); respect for persons and differences in opinions; debriefing students after completing learning activities (for example, after discussing or debating a chemical issue). For more detail regarding legislation and compliance, refer to page 8 of the study design.

Contemporary science issues The VCE Chemistry Study Design enables students to engage with contemporary science- related issues by building their capacities to explain phenomena scientifically, design and evaluate scientific investigations, and draw evidence-based conclusions. Students see how science works as a process by undertaking their own scientific investigations that involve generating, collecting and analysing data and exploring the nature of evidence. Teachers are advised to provide students with learning opportunities that allow students to critically evaluate the stories, claims, discoveries and inventions about science they hear and read in the media and to examine the relevance of science in their everyday lives. The following table shows how students can draw links between scientific concepts studied across Units 1 to 4 and their applications in relation to issues discussed in the media.

Unit Concept Issues 1 Impacts of polymer production Use of polyamide (nylon) engineering and use plastics as a replacement for metal in cars that result in lighter cars requiring less fuel consumption but have associated issues related to collision safety Use of epoxy resins in the production of the rotor of modern wind turbines for increased efficiency contrasted with health concerns related to epoxy resin production 2 Chemical nature of contaminants Levels at which chemical contaminants become a problem for society Fluoridation of water supplies

© VCAA 2016 8 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS 3 Energy generation from Greenhouse gas emissions generated by renewable and non-renewable the combustion of different fuels fuels Environmental impacts of the use of different fuels Renewability of different fuel sources 4 Chemical structures and Natural and artificial sweeteners properties of different food Saturated, monounsaturated and components polyunsaturated fatty acids Food labelling of trans-fats Glycaemic index of foods Dietary requirements

Sourcing contemporary science issues Contemporary chemical issues, discussions, reports, research and debates are accessible through the media or the internet. In particular, access to up-to-date information facilitates the research investigation in Unit 1 requiring the use of secondary data, the evaluation of chemistry-based issues related to water quality in Unit 2, energy production and use in Unit 3 and food quality in Unit 4, and sourcing of background research for the practical investigations in Units 2 and across Units 3 and 4. Teachers may also adapt research scenarios and reports to create assessment tasks (see Appendix 7), for example data analysis, evaluation of research, media response, response to an issue or a report using secondary data, where students are expected to apply their understanding of chemistry concepts in unfamiliar situations. Although original chemistry research reports are accessible, many require subscription and most are written for a research audience. For secondary school purposes, teachers and students may access reports, videos and summaries of contemporary chemistry research and expert commentary through popular science journals (for example, Cosmos, The Scientist, Nature, and Scientific American) and online science media outlets where areas of interest can be filtered (for example, Australian Science at www.australianscience.com.au, ScienceAlert at www.sciencealert.com and Science Daily at www.sciencedaily.com.au).

Scientific investigations

Designing scientific investigations Investigations are integral to the study of VCE Chemistry across Units 1 to 4. Some investigations across Units 1 to 4 in VCE Chemistry will be student-designed. A scientific inquiry approach involves asking or responding to a question and then performing experiments and reporting findings in response to the question. In any investigation, primary data may be generated and/or secondary data collected to test hypotheses, predictions and ideas; to look for patterns, trends and relationships in data; and to draw evidence-based conclusions. Appendices 1–4 provide more information about the broad scope of scientific inquiry. Appendix 1: Types of scientific inquiry Appendix 2: Scientific inquiry methods Appendix 3: Controlled experiments and hypothesis formulation Appendix 4: Defining variables

Topic selection phase The selection of a suitable topic for investigation may be initiated in a number of ways, including: through direct observation of, and curiosity about, an object, an event, a phenomenon, a practical problem or a technological development; as a result of anomalous or surprising investigation results; as an extension of a previous inquiry; from analysis of qualitative and/or quantitative data; and from research involving secondary data. Once the topic has been identified students articulate a research question for investigation. Questions may be generated from brainstorming or teachers may provide a question or scaffold the development of an appropriate testable hypothesis that students can adapt and investigate. In controlled experiment types of inquiry, a hypothesis is developed from a research question of interest and provides a possible explanation of a problem that can be tested experimentally. Controlled experiments involve an exploration of whether or not there is a relationship between variables and therefore require that students identify which variables will be investigated and which will be controlled. A useful hypothesis is a testable statement that may include a prediction. An example of hypothesis formulation is included in Appendix 3. For research questions related to inquiry types that do not lend themselves to developing an accompanying hypothesis, for example in exploratory or qualitative research, students should work directly with their research questions. Further information related to controlled experiments and hypothesis formulation is provided in Appendix 3.

Planning phase Prior to undertaking an investigation, students should produce a plan that outlines their reasons and interest in undertaking the investigation, defines the chemical concepts involved, identifies short-term goals, lists the materials and equipment required, outlines the design of any experiment including sampling protocols where relevant, notes any anticipated problems, identifies and suggests how potential safety risks can be managed and outlines any ethical issues. They may also make predictions about investigation outcomes based on their existing knowledge. In planning controlled experiment types of investigations students formulate a hypothesis that can be tested by the collection of evidence. They should identify the independent, dependent and controlled variables in their experiment and discuss how changing variables may or may not affect the outcome. Students should be able to explain how they expect that the evidence they collect could either refute or support their hypothesis. In planning an investigation, students may undertake relevant background reading. In addition, students should learn the correct use of scientific conventions, including the use of standard notation and International System (SI) units and how to reference sources and provide appropriate acknowledgments. A detailed explanation of types of variables is provided in Appendix 4.

© VCAA 2016 10 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Investigation phase In the investigation, students will generate primary or collect secondary qualitative and/or quantitative data as evidence. Data can be derived from observations, laboratory experimentation, fieldwork and local and/or global databases. During the investigation students should note any difficulties or problems encountered in generating and/or collecting data. Data should be recorded in a form according to the plan, for subsequent analysis and relevance to the investigation.

Reporting phase An examination and analysis of the data may identify evidence of patterns, trends or relationships and may subsequently lead to an explanation of the chemical phenomenon being investigated. For VCE Chemistry, the analysis of experimental data requires a qualitative treatment of accuracy, precision, repeatability, reproducibility, validity, uncertainty, and random and systematic errors. For more detailed information refer to the section ‘Measurement in science’. Students consider the data collected and make inferences from the data, report personal errors or problems encountered and use evidence to answer the research question. They consider how appropriate their data is in a given context, evaluate the validity of the data and make reference to its repeatability and/or reproducibility. Types of possible errors, human bias and uncertainties in measurements, including the treatment of outliers in a set of data, should be identified and explained. For an investigation where a hypothesis has been formulated, interpretation of the evidence will either support the hypothesis or refute it, but it may also pose new questions and lead the student to revising the hypothesis or developing a new one. In reaching a conclusion the student should identify any judgments and decisions that are not based on the evidence alone but involve broader environmental, social, political, economic and ethical factors. The initial phases of the investigation (topic selection, planning and investigation) are recorded in the student logbook while the report of the investigation can take various forms including a written report, a scientific poster or an oral or a multimodal presentation of the investigation. Detailed information about scientific poster sections is included in Appendix 5 and suggestions for effective scientific poster communication are elaborated in Appendix 6.

Graphical representation of data To explain the relationship between two or more variables investigated in an experiment, data should be presented in such a way as to make any patterns and trends more evident. Although tables are an effective means of recording data, they may not be the best way to show trends, patterns or relationships. Graphical representations can be used to more clearly show whether any trends, patterns or relationships exist. The type of graphical representation used by students will depend upon the nature of the investigation and the type of variables investigated: pie graphs and bar charts can be used to display data in which one of the variables is categorical line graphs can be used to display data in which both the independent and dependent variables are continuous lines of best fit can be used to illustrate the underlying relationship between variables scattergrams can be used to show an association between two variables © VCAA 2016 11 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS sketch graphs (not necessarily on a grid; no plotted points; labelled axes but not necessarily scaled) can be used to show the general shape of the relationship between two variables. When drawing graphs, students should note that: the independent variable is represented on the horizontal axis while the dependent variable is represented on the vertical axis the existence of a correlation does not necessarily establish that there is a causal relationship between two variables not all experiments will show a correlation between variables common types of relationships in physics include linear, power and sometimes exponential. Students should understand why it is important not to ‘force data through zero’. In drawing conclusions they should examine patterns, trends and relationships between variables with the limitations of the data in mind. Gradients and y-intercepts should be considered in terms of what these may indicate about the relationship between independent and dependent variables. Conclusions drawn from data must be limited by, and not go beyond, the data available.

Student investigations

Student-designed investigations The formulation of an investigable research question and proposal for an associated methodology is crucial to enabling students to meet unit outcomes. Teachers should ensure that proposed hypotheses and methodologies enable students to proceed with investigations such that all safety and ethical guidelines are followed, as specified on pages 8 and 9 of the study design, and where students could reasonably expect to generate primary data that can be suitably processed and analysed. In particular, the general guiding principle behind ethical research is to do no harm to participants, the researcher and the community. Teachers should guard against research that may be inappropriate for inexperienced student researchers and be mindful of particular sensitivities within their school communities and the broader community. Due to the scope of scientific investigations, students must be practical and realistic when deciding on investigation topics. Teachers need to be equally pragmatic when counselling students about their choice of research topic and when guiding the student in the formulation of the research question. Appropriate teacher intervention not only minimises risks but also serves as formative feedback for students. Schools should have in place approval mechanisms, either through ethics committees or approval authorities within the school, to ensure that students undertake appropriate research.

Management of the Units 3 and 4 practical investigation One practical investigation across VCE Chemistry Units 3 and 4 must be undertaken and reported in a scientific poster format and assessed as part of Unit 4 School-assessed Coursework. The practical investigation must be based on content in Unit 3 and/or Unit 4 Areas of Study 1 and/or 2. It would be expected that the investigation is a coupled or open type of scientific inquiry. The practical investigation can be undertaken at any time across Units 3 and 4. The student must design an investigation that will generate primary data sets and involve consideration of variables, including through laboratory experiments, fieldwork, model construction, simulations involving random data and the use of databases. Teachers must ensure that all proposed investigation procedures and materials comply with all relevant safety, health and ethical regulations and/or codes of conduct. Students may work in groups to generate data,

© VCAA 2016 12 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS but all data manipulation, analysis, evaluation and reports must be the work of the individual student. Authentication of student work may be monitored through a variety of strategies including classroom observation during practical work, review of student logbooks, student interviews, setting of specific questions related to the investigation as part of the student assessment, and completion of data generation, manipulation, analysis and evaluation in class time. Time outside class may be allocated to background research and to completing references and/or acknowledgments.

Scientific posters Scientific poster templates available on the Internet may be used provided that the mandated poster sections (title, introduction, methodology, results, discussion, conclusions, references and acknowledgments) are included. The use of a template can help minimise many common communication faults by keeping column alignments logical, including mandated sub-headings that provide clear cues as to how readers should travel through poster elements and maintaining sufficient ‘white space’ so that clutter is reduced. There is no mandated VCAA style for the use of person or voice in writing a scientific poster, since the scientific community has not reached a consensus about which style it prefers. Increasingly, using first person (rather than third person) and active (rather than passive) voice is acceptable in scientific reports, because arguably this style of writing conveys information more clearly and concisely. However, this choice of person and voice brings two scientific values into conflict – objectivity versus clarity – which may account for the different viewpoints in the scientific community. Use of tense is dependent on the section of the report: when describing something that has already happened (for example, the investigation procedure) then past tense is used, as in ‘The aim of the experiment was to…’; when describing something that still exists (for example, the report, theory and permanent equipment) then the present tense is used, as in ‘The purpose of this report is to…’, ‘Le Chatelier’s principle states that…’ and ‘A calorimeter can be used to…’. Detailed information about scientific poster sections is included in Appendix 5 and suggestions for effective scientific poster communication are elaborated in Appendix 6.

Maintenance of a logbook Students must maintain a logbook of practical activities for each of Units 1 to 4. The logbook is a record of the student’s practical and investigative work involving the generation of primary and/or collection of secondary data. Its purposes include providing a basis for further learning, for example, contributing to class discussions about demonstrations, activities or practical work; reporting back to the class on an experiment or activity; responding to questions in a practical worksheet or problem-solving exercise; or writing up an experiment as a formal report or a scientific poster. No formal presentation format for the logbook is prescribed. The logbook may be digital and/or paper-based. Data may be qualitative and/or quantitative and may include the results of guided activities or investigations; planning notes for experiments; results of student-designed activities or investigations; personal reflections made during or at the conclusion of demonstrations, activities or investigations; simple observations made in short class activities; links to spreadsheet calculations and other student digital records and presentations; notes and electronic or other images taken on excursions; database extracts; web-based investigations and research, including online communications and results of simulations; surveys; interviews; and notes of any additional or supplementary work completed outside class. All logbook entries must be dated and in chronological order. Investigation partners, expert advice and assistance and secondary data sources must be acknowledged and/or referenced. © VCAA 2016 13 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Teachers may use student logbooks for authentication and/or assessment purposes.

Measurement in science

Overview A major aim of science is to develop explanations for natural phenomena and events that are supported by evidence. For VCE Chemistry students this involves considering the quality of evidence and of explanations that are based upon it so that questions such as ‘Can I rely on the data I have generated when drawing conclusions?’ and ‘Does the difference between one measurement and another indicate a real change in what is being measured?’ are central to any discussion of investigation results prior to formulating a conclusion. The following section defines important terms. These terms arise from investigations and evaluations of scientific claims presented in the public domain, consistent with the terminology used by scientists but adapted (i.e. simplified without deviation from internationally agreed definitions) for VCE Chemistry have been provided below. The main reference source is International Vocabulary of Metrology – Basic and General Concepts and Associated Terms, VIM, 3rd edition, JCGM 200:2008 and accessed at: www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf.

Measurement terms VCE Chemistry requires that students can distinguish between and apply the terms ‘accuracy’, ‘precision’, ‘repeatability’, ‘reproducibility’ and ‘validity’ when analysing their own and others’ investigation findings. An understanding of the terms ‘accuracy’ and ‘precision’ is also important in the analysis and discussion of investigations of a quantitative nature.

Accuracy A measurement result is considered to be accurate if it is judged to be close to the ‘true’ value of the quantity being measured. The true value is the value (or range of values) that would be found if the quantity could be measured perfectly. For example, if an experiment is performed and it is determined that a given substance had a mass of 2.70 g, but the true value of mass is 3.20 g, then the measurement is not accurate since it is not close to the true value. The difference between a measured value and the true value is known as the ‘measurement error’. ‘Accuracy’ is not a quantity and therefore cannot be given a numerical value. It is allowable for a measurement to be described as being ‘more accurate’ when its method and/or instruments clearly reduce measurement error, such as using a triggered electronic timer system compared to a hand-operated stopwatch. Accuracy may not be quantified: ‘measurement error’ is the quantity used to evaluate how close a measured value is to the true value. While accurate measurements and observations are important in all science experiments, in some cases it may not be possible to determine the accuracy of a measurement since a true (or accepted) value for a physical quantity may be unknown at the conditions under which the experiment is conducted. For example, the accepted value of the ionic product of water of 1.0 x 10-14 M2 only applies at 25 ºC. This value does not apply at other temperatures. As a result, the pH of pure water is 7.0 only at 25 ºC. Many practical activities in the classroom involve an experimental setup that is unique to the student; for example, determination of the conductivity of the water in the water tank or dam on the student’s property. In such instances, there is no accepted single value with which comparisons can be made. © VCAA 2016 14 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Precision Experimental precision refers to how closely two or more measurement values agree with each other. A set of precise measurements will have very little spread about their mean value. For example, if a given substance was weighed five times, and a mass of 2.70 g was obtained each time, then the experimental data are precise. However, this gives no indication of how close the results are to the true value and is therefore a separate consideration to accuracy, so that if the true mass in the above example was 3.20 g then these data are precise but inaccurate. Quantitatively, a measure of precision would be a measure of spread of measured values. A measured mass of 2.7 g ± 0.1 g is less precise than 2.702 g ± 0.001 g. A quantitative treatment of precision is beyond the scope of the VCE Chemistry Study Design.

Replication of procedures: repeatability and reproducibility Experimental data and results must be more than one-off findings and should be repeatable and reproducible to draw reasonable conclusions. Repeatability refers to the closeness of agreement between independent results obtained with the same method on identical test material, under the same conditions (same operator, same apparatus and/or same laboratory). Reproducibility refers to the closeness of agreement between independent results obtained with the same method on identical test material but under different conditions (different operators, different apparatus and/or different laboratories). The purposes of reproducing experiments include checking of claimed precision and uncovering of any systematic errors from one or other experiments/groups that may affect accuracy. Experiments that use subjective human judgment(s) or that involve small sample sizes or insufficient trials may also yield results that may not be repeatable and/or reproducible.

Validity A measurement is ‘valid’ if it measures what it claims to be measuring. Both experimental design and the implementation should be considered when evaluating validity. Data are said to be valid if the measurements that have been made are affected by a single independent variable only. They are not valid if the investigation is flawed and control variables have been allowed to change or there is observer bias.

Experimental uncertainty and error It is important not to confuse the terms ‘error’ and ‘uncertainty’, which are not synonyms. It is also important not to confuse ‘error’ with ‘mistake’ or ‘personal error’. Error, from a scientific measurement perspective, is the difference between the measured value and the true value of what is being measured. Uncertainty is a quantification of the doubt associated with the measurement result. The VCE Chemistry Study Design requires only a qualitative treatment of uncertainty. Experimental uncertainties are inherent in the measurement process and cannot be eliminated simply by repeating the experiment no matter how carefully it is done. There are two sources of experimental uncertainties: systematic effects and random effects. Experimental uncertainties are distinct from personal errors.

Personal errors Personal errors include mistakes or miscalculations such as measuring a height when the depth should have been measured, or misreading the scale on a thermometer, or measuring the voltage across the wrong section of an electric circuit, or forgetting to divide the diameter

© VCAA 2016 15 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS by two before calculating the area of a circle using the formula A = πr 2. Personal errors can be eliminated by performing the experiment again correctly the next time, and do not form part of an analysis of uncertainties.

Systematic errors Systematic errors are errors that affect the accuracy of a measurement. Systematic errors cause readings to differ from the true value by a consistent amount each time a measurement is made, so that all the readings are shifted in one direction from the true value. The accuracy of measurements subject to systematic errors cannot be improved by repeating those measurements. Common sources of systematic errors include: faulty calibration of measuring instruments (and uncalibrated instruments) that consistently give the same inaccurate reading for the same value being measured, poorly maintained instruments (which may also have high random errors), or faulty reading of instruments by the user (for example, ‘parallax error’).

Random errors Random errors affect the precision of a measurement and are always present in measurements (except for ‘counting’ measurements). These types of errors are unpredictable variations in the measurement process and result in a spread of readings. Common sources of random errors are variations in estimating a quantity that lies between the graduations (lines) on a measuring instrument, the inability to read an instrument because the reading fluctuates during the measurement, and making a quick judgment of a transient event, for example, measuring the temperature at which a crystal first forms as a solution cools in order to construct a solubility curve. The effect of random errors can be reduced by making more or repeated measurements and calculating a new mean and/or by refining the measurement method or technique.

Outliers Readings that lie a long way from other results are sometimes called outliers. Outliers should be further analysed and accounted for, rather than being automatically dismissed. Extra readings may be useful in further examining an outlier.

Significant figures Non-zero digits in data are always considered significant. Leading zeros are never significant whereas following zeros and zeros between non-zero digits are always significant. For example, 075.0210 contains six significant figures with the zero at the beginning not considered significant. A whole number may be a counting number or a measurement and determination of significant figures varies in the literature. For the purpose of the VCE Chemistry Study Design, whole numbers will have the same significant figures as number of digits, for example 400 has three significant figures while 400.0 has four.

Using a significant figures approach, one can infer the claimed accuracy of a value. For example, 400 is closer to 400 than 399 or 401. Similarly 0.0675 is closer to 0.0675 than 0.0674 or 0.0676. Columns of data in tables should have the same number of decimal places, for example, measurements of lengths in centimetres or time intervals in seconds may yield the following data: 5.6, 9.2, 11.2 and 14.5. Significant figure rules should then be applied in subsequent data analysis.

© VCAA 2016 16 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Calculations in chemistry often involve numbers having different numbers of significant figures. In mathematical operations involving: addition and subtraction, the student should retain as many digits to the right of the decimal as in the number with the fewest significant digits to the right of the decimal, for example: 386.38 + 793.354 - 0.000397 = 1179.73 multiplication and division, the student should retain as many significant digits as in the number with the fewest significant digits, for example: 326.95 x 10.2 ÷ 20.322 = 164. Intermediate results in calculations should retain at least one significant figure more than such analysis suggests until the final result is ascertained.

Unit 1: How can the diversity of materials be explained? This unit focuses on chemical structure and bonding. Practical activities should not be limited to assessment tasks; they may be used to introduce a chemical concept, to build understanding of a chemical concept or skill and to practise specific scientific skills; for example, modelling atomic, ionic, molecular, lattice and polymer structures, performing chemical reactions, and determining empirical and molecular formulas. Area of Study 1: How can knowledge of elements explain the properties of matter? Outcome 1: Examples of learning activities Relate the position of view emission spectra of various elements; perform flame tests elements in the periodic by heating various metallic compounds in a flame; use a table to their spectrometer to observe and compare the emission spectra properties, investigate obtained from the flames; use these findings to suggest the structures and how the different colours in fireworks may be generated properties of metals interpret a series of ionisation energies as evidence for and ionic compounds, electron shells and subshells and calculate mole conduct an introductory experiment to demonstrate the variety quantities. of ways elements and compounds can react; write precise observations using appropriate chemical vocabulary; reflect on observations by classifying them on the basis of involvement of the five senses (sight, smell, touch, taste, hearing) write a media article or produce an infographic on a useful isotope contribute to a whole class activity to create a relative scale (may be three-dimensional) to display on the classroom wall discuss Herbert Spencer’s quote that ‘Science is organized knowledge’ in terms of the value of placing elements into a periodic table conduct experiments demonstrating trends within the periodic table based on data related to the physical and chemical properties of a selection of elements and their position in the periodic table; work in groups to predict the properties of other elements; compare predictions with actual properties create a periodic table using representations of the electronic structures of elements 1-36; annotate the table to highlight trends in structures and properties use simulations to investigate atomic structure, for example Build an Atom; Isotopes and Atomic Mass; Models of the Hydrogen Atom https://phet.colorado.edu/en/simulation/build-an-atom participate in group work to model the structure and properties of different metals compare the physical properties of metals, for example malleability, hardness, electrical conductivity, heat conductivity, and density examine metallic crystals under a stereomicroscope © VCAA 2016 18 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS compare the chemical properties of main group metals and transition metals, for example, reaction with water and reaction with acid (where safe), including testing for products and formation of colourless and coloured compounds perform simple displacement reactions to deduce an activity series of metals extract copper from a solution of a copper ore using electrolysis and/or extract copper by heating malachite and carbon illustrate Dalton’s theory that atoms are rearranged in chemical reactions by carrying out a series of experiments whereby a sample of copper metal is reacted to form a series of copper compounds and then extracted as the metal model the properties of alloys using plasticine and sand, for example www.nuffieldfoundation.org/practical- chemistry/modelling-alloys-plasticine investigate practically the trends in reactivity as you go down a group in the periodic table, for example the alkaline earth metals test the rate of corrosion of iron nails that are uncoated and coated with different materials, including different metal foils, and embedded in agar gel containing phenolphthalein; record observations over a period of several days investigate experimentally the effects of annealing, quenching, and tempering on metals using metal pins or nails; determine which type of heat treatment results in the hardest and/or the strongest metal undertake an internet search or invite a guest expert to outline contemporary research into metallic nanomaterials participate in group work to model the structures and properties of different ionic compounds use non-spherical particles such as rice, matches or lollies to determine the relationship between the shape of the particle and the fraction of space that it occupies; investigate how characteristics such as coordination number, orientation order or the random close packing fraction depend on different parameters investigate the physical properties of ionic compounds, for example malleability, hardness, density, electrical conductivity, and heat conductivity examine mineral crystals using a hand lens and a stereomicroscope; investigate the factors that affect ionic crystal formation over time, for example temperature, humidity simulate crystal formation in rocks by making chocolate fudge under different temperature conditions determine experimentally the empirical formula of an ionic compound, for example magnesium oxide or copper(II) oxide demonstrate the allotropes of sulfur, for example © VCAA 2016 19 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS www.nuffieldfoundation.org/practical-chemistry/allotropes- sulfur create a classroom display of one mole of different substances (students weigh out the different substances after calculating the mass required) visualise the mole by calculating how deep a ‘blanket’ of a mole of marshmallows over Australia would be, or how high a ‘tower’ made from a mole of dollar coins or sheets of A4 paper would reach, or how long it would take to count a mole of marbles if you counted one every second every day until finished interpret mass spectra to determine relative atomic masses perform calculations of relative atomic masses from abundances and relative isotopic masses use an ‘if…then…when…’ structure to develop hypotheses related to empirical formulae determinations and test the predictions inherent in these hypotheses solve quantitative exercises involving the mole and Avogadro’s constant Detailed example SIMULATION OF CRYSTAL FORMATION IN ROCKS USING CHOCOLATE FUDGE Background Why do some rocks that are made of the same minerals have different sized crystals in them? What effect will faster versus slower cooling have on the formation of crystals? The inside of Earth is hot enough to melt rocks. Both magma and lava are forms of hot, molten rock, with the main difference being where they are located. Magma is deep underground in chambers beneath volcanoes while lava is the molten material that is expelled from volcanoes when they erupt. When magma and lava cool and solidify, igneous rock forms. Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma and lava solidify. Magmas, retained deep within the Earth, cool very slowly over tens of thousands of years to produce plutonic rocks such as granite and gabbro. The more slowly the magma cools, the larger the crystals. Lavas, erupted at Earth’s surface, cool quickly to form volcanic rocks such as basalt and obsidian. These rocks are smoother and contain much smaller crystals that may not be visible even with the use of a hand lens. In this activity, students simulate the process of igneous rock formation by making chocolate fudge and compare fudge textures of samples that are cooled quickly with those that are cooled slowly. General procedure Obtain a recipe for fudge and organise to make the fudge, up to the point where the fudge is to be cooled. Divide the cooked fudge mix into two batches. Spoon equal quantities of each fudge mix into two separate greased cake tins of the same size so that the fudge mix in each tray is at least 2 cm thick. Place one cake tin into the refrigerator, and leave the other cake tin out at room temperature. When both fudge mixes have cooled completely, cut each fudge block into 2 cm blocks. Test the constituency of each of the two types of cooled fudge blocks: observe each type of fudge block carefully; note any similarities and/or differences in a table in your logbooks, for example, differences in texture or colour observe each type of fudge block using a hand lens; slice thinly and observe under a

© VCAA 2016 20 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS stereomicroscope; note any similarities and/or differences in a table in your logbooks, for example, differences in texture or colour Taste each type of fudge block; note any similarities and/or differences in a table in your logbooks, for example, differences in flavour or texture. Questions Students could respond to a series of graded questions, for example: Explain: How does the nature of the cooling process for the fudge mimic the environmental conditions involved in rock formation? Design: Design a controlled experiment to further investigate other factors that may affect crystal formation. Apply: Model how some igneous rocks may have a glassy appearance in terms of their formation. Model: Use a molecular modelling kit or an animation program to demonstrate why slower cooling rates encourage formation of an ordered, crystal structure while faster cooling rates lead to less orderly crystal structures. Propose: Suggest why, unlike sedimentary rocks, igneous rocks do not contain fossils.

© VCAA 2016 21 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Area of Study 2: How can the versatility of non-metals be explained? Outcome 2: Examples of learning activities Investigate and explain individually create ball-and-stick models of simple polyatomic the properties of carbon molecules of different shapes, for example H2, F2, Cl2, O2, lattices and molecular HCl, HF, H2O, H2S, NH3, CH4, CO2 or BF3; sketch them using substances with appropriate chemical conventions to indicate their three- reference to their dimensional shape; annotate the models to show polarities structures and bonding, and to explain their shapes; bring together the different use systematic molecular models to show the alignments of the molecules nomenclature to name and annotate them to show the operation of the organic compounds, intermolecular bonding forces and explain how capillary action, or capillarity, can be demonstrated by the polymers can be tendency of a liquid to rise in a narrow tube and results designed for a purpose. from the intermolecular attractions within and between the liquid and solid materials: investigate capillary action by formulating hypotheses and undertaking experiments for one of the following research questions: Is capillary action related to the polarity of the liquid? How does the capillary diameter affect capillary action? How is capillary action affected by different capillary tube materials, for example glass or plastic? Does temperature affect capillary action? How does capillary action differ for polar liquids of different densities? How does capillary action differ for non-polar liquids of different densities? graph the boiling points of alkanes and explain these in terms of intermolecular bonding chocolate appears to be a solid material at room temperature but melts when heated to around body temperature; when chocolate is cooled down again, it often stays molten even at room temperature; investigate the factors that affect the temperature range over which chocolate can exist in both molten and ‘solid’ states a wire with weights attached to each end is placed across a block of ice: investigate the phenomenon that the wire can pass through the ice without cutting it as an introduction to organic chemistry, capture an image of a local environment inside or outside the classroom; print the images and label all physical objects, or parts of objects, as ‘organic’ or ‘inorganic’; later, re-visit the labelled images and re-label objects as required research why crude oil reserves around the world have different hydrocarbon compositions; identify uses for crude oil fractions; justify whether oil reserves around the world can be ranked in terms of usefulness use steam distillation to extract oil from eucalyptus leaves, ti- tree leaves, olives, orange peel or cloves; improve the method by investigating different collection, heating and extraction methods, for example, different aged leaves, crushing versus slicing plants, temperature, and heating rate

© VCAA 2016 22 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS visit an olive leaf distillery or oil refinery; use images and brief descriptions to summarise processes; identify safety precautions involved in processing; note in logbook three points of interest create models of, and name, a range of alkanes, alkenes and alkynes, including structural isomers predict trends in the melting points and boiling points of a range of alcohols, carboxylic acids and/or non-branched esters solve quantitative exercises involving empirical and molecular formulas of organic compounds use a predict-observe-explain approach to investigate volume contraction in alcohol-water mixtures use a published recipe to make cheese or sour cream; identify how organic chemistry knowledge and science inquiry skills may be applied to identify factors that may affect the quality of the product; undertake and report on an investigation that attempts to improve the quality of the product investigate some allotropes of carbon by creating and annotating models of diamond, graphite, a ‘buckyball’ and a carbon nanotube; compare similarities and differences between their structures; explain their properties in terms of their structures investigate the motion of water droplets falling on a hydrophobic surface (for example, coated with Teflon or soot) work in groups to create multiple models of the ethene molecule then join them up to form a segment of a polyethene (PE) molecule; modify the models of ethene molecules to create models of propene molecules and join them to build a model of a segment of a polypropene (PP) molecule; repeat to build models of vinyl chloride molecules and a segment of a polyvinyl chloride (PVC) molecule; use data about the mean mass or length of PE molecules to calculate how long a model of a complete PE molecule would be on this scale; use the models to compare and explain their properties and uses ‘slime’ is used in hot or cold packs because it is not dangerous if it leaks out, and is formed when polyvinyl alcohol (PVA) has been crosslinked by the addition of borax

Na2B4O7.10H2O (sodium tetraborate); use a standard recipe for slime and investigate experimentally the effects of: changes in amounts of borax on viscosity of the slime changes in pH on the properties of slime investigate experimentally the physical properties of thermoplastic and thermosetting polymers; look at: electrical and heat conductivity, density, hardness, response to immersion in a hot water bath, reaction when a very small sample is exposed to a flame discuss Wernher von Braun’s comment that: ‘Research is what I’m doing when I don’t know what I’m doing’ in terms of undertaking chemical investigations or with reference to an

© VCAA 2016 23 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS example of contemporary chemistry research debate that ‘Plastics should be banned’ or that ‘Plastics are the best materials the world has ever seen’ design and undertake experiments to investigate whether there is a difference in the recyclability of thermosetting and thermoplastic polymers discuss the significance of size and surface area in the application of nanoparticles conduct a web search and write a report or prepare a web page on the development, properties and uses of a selected customised polymer, for example dentrimers used in medicine or intelligent polymers used in textiles conduct a web search and produce an infographic to explain why a spider’s silk looks like a string of pearls; explain how spider’s silk can appear fragile and yet has a tensile strength similar to steel; identify and outline contemporary applications of spider’s silk design experiments to compare the relative biodegradabilities of different polymers labelled as ‘biodegradable’; investigate environmental factors that affect biodegradability, for example, UV light, pH, heat, water use a problem-based learning approach to investigate an issue in chemistry, for example, safety issues associated with the use of nanoparticles in the manufacture of sunscreens; replacement of plastic shopping bags with paper alternatives view computer-generated models of covalent molecular compounds; research and explain how computer modelling of molecules can be used in medicinal drug design and customisation of polymers for purpose identify an object that could be made from a polymer and identify how a particular set of properties could be achieved in the object through selection of appropriate monomers or polymer characteristics organise a site tour to a polymer manufacturing or recycling plant; summarise processes, safety aspects and three major points of interest in logbooks

Detailed example PREDICT-OBSERVE-EXPLAIN: INVESTIGATING VOLUME CONTRACTION IN ALCOHOL-WATER MIXTURES Aim To investigate and explain volume contraction in terms of relative bonding strengths within and between covalent substances. Introduction When ethanol and water are mixed together the final volume is less than the sum of the separate volumes before mixing. This shrinkage is known as ‘volume contraction’ and is due to the strength of hydrogen bonding. Hydrogen bonding is classified as weak bonding but is stronger between water molecules than it is between alcohol molecules. This contraction can have vital consequences in everyday applications, for example alcohol absorption into the bloodstream and the resultant volume contraction can upset the plasma concentration of various chemicals in the blood and result in a number of medical © VCAA 2016 24 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS complications. Science skills Teachers should identify and inform students of the relevant key science skills embedded in the task. Health and safety notes Safety data sheets should be made available for all chemicals used Safety warning: alcohol water mixtures can burn even when the amount of alcohol is less than 50%, especially at higher temperatures. Procedure Part A Students: Measure the volume contractions due to various mixtures of ethanol and water and enter data into a table in the logbook.

Volume of water Volume of Final volume of % contraction (mL) ethanol mixture (mL) (mL) 25.0 75.0 50.0 50.0 75.0 25.0

Use the data to determine the point of maximum contraction (further proportional mixes of water and ethanol will be required – enter data into the table). Part B Teachers use a predict-observe-explain approach to explore students’ understanding of the bonding within and between molecular substances, including that the strength of dispersion forces becomes more significant as the molecular mass of an alcohol increases. Students complete the following table by making predictions about different experiments related to volume contraction, investigating and recording observations related to the experiments and explaining their observations in terms of the bonding involved.

Experiment Prediction Observatio Explanation in ns terms of bonding If volume contraction is due to hydrogen bonding, predict what will happen when water is mixed with methanol If volume contraction is due to hydrogen bonding, predict what will happen when water is mixed with propan-1-ol If volume contraction is due to hydrogen bonding, predict what will happen when water is mixed with propan-2-ol If volume contraction is due to hydrogen bonding, predict what will happen when water is mixed with methyl propan-2-ol © VCAA 2016 25 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS If volume contraction is due to hydrogen bonding, predict what will happen when water is mixed with butan-3-ol If heat affects the strength of hydrogen bonding, predict the % contraction over a range of temperatures

Questions A series of graded questions could be set for students to answer in their logbook, for example: Compare: In what ways is volume contraction similar to, and different from, combining sand and marbles in a jar? Explain: Use a series of annotated images including reference to intermolecular bonding to illustrate how temperature affects volume contraction. Evaluate: Collate class results for volume contraction and comment on the accuracy, precision and validity of the results. Generalise: Suggest a relationship between nature of hydrogen bonding and volume contraction. Reflect: Review your predictions in this activity and comment on Vera Rubin’s quote that: ‘Science progresses best when observations force us to alter our preconceptions’. Imagine: Under what circumstances could volume expansion occur?

Area of Study 3: Research investigation Outcome 3: Examples of learning activities Investigate a question the teacher provides a list of possible research questions related to the from pages 15–18 of the VCE Chemistry Study Design; development, use students submit a proposed timeline and research plan and/or modification of a related to a research question of interest; a negotiated selected material or research question is undertaken by the student and chemical and monitored by the teacher communicate a groups of students investigate a selected and/or negotiated substantiated response research question from the set of possible questions on to the question. pages 15–18 of the VCE Chemistry Study Design; each member of the group contributes a nominated newspaper item related to the research question in a class chemistry e- newspaper (for example, letter to the editor, a report of a chemical issue, survey results from a public opinion poll related to a chemical issue, a cartoon about a chemical issue, interviews with a chemist or other chemistry-based professional) the teacher selects questions from each of the six topic areas listed on pages15–18 of the VCE Chemistry Study Design that have a ‘case study’ theme; students work individually or in groups to provide a response to the case study using an inquiry approach; sample questions in this category include: How has biomimicry been used to develop different materials? What biomimicry research is currently happening? How are ocean oil spills treated? Does the cleaning up of oil spills lead to a different set of problems for society? Are sunscreens containing nanoparticles safe?

© VCAA 2016 26 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS What precautions should be taken in working with nanomaterials? Should a product’s life cycle be considered prior to the product being available to consumers? Is ‘green chemistry’ a social and political priority? the teacher selects questions from each of the ten options listed on pages 15–18 of the VCE Chemistry Study Design that have an ‘experimental’ theme; students work individually or in groups to provide a response to investigate the research question of interest; sample questions in this category include: Does surfactant biodegradability affect performance? How do the recycling capacities of different types of polymers compare? How are the properties of metals affected by heat treatment? How can crystal formation be sped up?

Detailed example AN INQUIRY APPROACH TO EXPLORING A CASE STUDY IN CHEMISTRY The research investigation in this area of study must build on knowledge and skills developed in Unit 1 Area of Study 1 and/or Area of Study 2. The focus is on students being able to communicate a response to a selected research question. Teachers must consider the management logistics of the investigation, taking into account number of students, available resources and student interest. The following questions require consideration: To whom will students be expected to communicate their results? What alternative communication formats will students be able to consider? To what extent, and at what stages, will students work independently and in groups? To what extent will students work on their research and response inside and outside class time, and how will student work be monitored and authenticated? Will time be allocated in class for students to present their work to other students? Background information This detailed example has been developed with an inquiry-based framework in mind. There are many methods by which students may undertake inquiry-based learning; this detailed example has been informed by the following article by Jeni Wilson and Kath Murdoch: http://extranetportal.bne.catholic.edu.au/re/REL/Documents/CU8%20What %20is%20inquiry%20learning.pdf In essence, the inquiry process involves a question, a hypothesis, data collection and analysis, drawing conclusions, making generalisations, reflection and authentic action. The process of answering their question should involve students considering prior knowledge to gather new ideas. Students should then gather new information (for case studies, this will mostly involve secondary data; however, some primary data may also be collected including surveys of public opinion) and organise this information into new ideas. They will then draw conclusions, reflect upon their learning and also take some sort of personal action related to a specific outcome and audience to conclude their investigation. Topic selection phase To manage the inquiry process in the class, the teacher determined that students could work independently or in groups to research questions related to one of four areas related to content across Unit 1 Area of Study 1 and Area of Study 2: How has biomimicry been used to develop different materials? What biomimicry research is currently happening? How are ocean oil spills treated? Does the cleaning up of oil spills lead to a different set of problems for society? Are sunscreens containing nanoparticles safe? What precautions should be taken in

© VCAA 2016 27 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS working with nanomaterials? Should a product’s life cycle be considered prior to the product being available to consumers? Is ‘green chemistry’ a social and political priority? The teacher provided relevant case studies related to these questions, but students were also able to research and provide their own case study of interest. The task involved students investigating the chemical aspects of the case study and responding to the case study by developing a relevant media product (such as an information pamphlet, YouTube video, multimedia product or community campaign) for a selected audience. Planning phase Communication of chemical concepts is the major focus of this task. Students should be clear about the purpose of the intended communication to a specified audience. Students may need guidance in considering appropriate communication formats for specific audiences. Teachers should work with students to: set timeframes and milestones for the task determine the nature of the work that is to be completed inside and outside the classroom check the scientific accuracy of content prior to students working on the response (communication) phase. Teachers could provide students with a template that structures the investigation into a series of timed phases. The template may subsequently be adapted by students as a personal work plan in their logbooks. Investigation phase It is important that students structure the research component into a set of manageable tasks that constitute a personal work program. Work in this phase can be done outside the classroom and recorded in students’ logbooks, with class time allocated to check on progress and the quality of material being researched. This activity provides students with opportunities to learn how to document resources and acknowledge contributions using standard conventions. Reporting phase Students could use a variety of formats to present their response to the investigation question to a specific audience. Teachers may wish to limit the number of formats used and to set time and/or word limits. The response communication should clearly address the question, demonstrate that the student understands the relevant chemical concepts and be appropriate for the nominated audience.

Unit 2: What makes water such a unique chemical? This unit focuses on water quality issues. Practical activities should not be limited to assessment tasks; they may be used to introduce a chemical concept, to build understanding of a chemical concept or skill and to practise specific scientific skills, for example, dilution, acid-base titrations, colorimetry, and construction and use of calibration curves.

Area of Study 1: How do substances interact with water? Outcome 1: Examples of learning activities Relate the properties of interpret and summarise data from world maps showing water water to its structure distribution and quality to identify five major points of and bonding, interest capture photos or images of a rapidly occurring phenomenon and explain the related to reactions in water; use the images and add text importance of the © VCAA 2016 28 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS properties and reactions to produce a photo essay or infographic of the phenomenon of water in selected contexts. demonstrate the polarity of water by bringing a charged rod slowly towards a stream of water from a tap; draw labelled diagrams that explain the resultant distortion of the water stream design and perform an experiment to determine the effect of temperature on the density of water determine qualitatively the solubility of a variety of solid, liquid and gaseous solutes in water; write equations for substances dissolving in water record observations related to the size of air bubbles and the speed at which they rise in liquids; devise and test a model of the relationship between bubble size and their speed in different liquids plot a solubility curve derived from experimental data; explain whether a plot of solubility versus amount of solute should pass through the origin (the point (0, 0) on the graph) compare the degree of solubility of a range of ionic salts and molecular substances in water, methanol and oil; account for differences set up a controlled experiment to investigate the percentage water loss from an open container of water compared with a container of water with a surface monolayer of a long- chain alcohol formulate a biodegradable ink for use with recyclable paper produce an animation to illustrate why ice is less dense than liquid water compare the specific heat capacities of water and cooking oil create and annotate a series of images to explain: why evaporation of water requires more energy than evaporation of methane, despite both molecules having similar molecular masses how the process of dissolving in water a crystal of salt differs from dissolving a crystal of sugar the movement of protons in acid-base reactions the movement of electrons in redox reactions create an imaginative response to: ‘What would Earth and its life forms be like if water followed the same trends in melting point and boiling point that are displayed by the other Group 16 hydrides?’ bubbles in a glass of sparkling water adhere to the walls of the glass at different heights: find a relationship between the average size of the bubbles and their height on the side of the glass organise the class into groups to formulate hypotheses and design and perform experiments so that each group investigates and reports on one of the following research questions: Can a saturated solution of sodium chloride dissolve any Epson salts? Can a saturated solution of sugar dissolve any Epson salts?

© VCAA 2016 29 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Can a saturated solution of Epsom salts dissolve any sodium chloride? Can a saturated solution of Epsom salts dissolve any sugar? Can a saturated solution of sodium chloride dissolve any sugar? Can a saturated solution of sugar dissolve any sodium chloride? How does solubility vary with temperature? How does solubility vary with the atomic mass of the solute? How does solubility vary with the polarity of the solute? use solubility rules to predict the outcomes of precipitation reactions and experimentally test the predictions; write ‘full’ and ionic equations for precipitation reactions that occur design a procedure to identify an unknown salt dissolved in a water sample adapt a scale such as Mohs Scale of Hardness to develop a solubility scale collect, individually, an empty package of processed food that contains salt or sugar; calculate total amount of salt or sugar for the product contained in the package; produce a class display to show increasing salt or sugar content for the food product use a multimeter to compare the total amount of electrolytes in various drinks, for example; tap water, mineral water, fruit juices, soft drinks, and sports drinks; research and provide a brief report on the function of electrolytes in the human body develop and test hypotheses through the investigation of a research question, for example ‘How can hard water be softened?’ confirm the Law of Conservation of Mass for a chemical reaction in a closed system; model the chemical reaction to show the rearrangement of atoms perform experiments to differentiate between strong and weak acids on the basis of conductivity, pH and rate of reaction with magnesium relate the strength and concentration of acids and bases to the safety procedures for their use discuss the accuracy, precision and validity of collated class measurements of the pH of a variety of everyday solutions, for example tap water, bottled mineral water, distilled water, saline solution, drain cleaner (sodium hydroxide), vinegar (acetic acid), dishwashing powder (sodium carbonate), cloudy ammonia, baking soda, battery acid (sulfuric acid), concrete cleaner (hydrochloric acid), albumin and yolk of an egg investigate indicator colours at different pH values create scales (a logarithmic scale versus an arithmetic scale) to + show the relative positions of solutions with [H3O ] of 1.0 M. 0.1 M. 0.01 M and 0.001 M perform simple redox reactions, for example combustion of © VCAA 2016 30 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS magnesium and metal displacement reactions; write balanced redox reactions including states; annotate equations to identify direction of electron flow, oxidising agents, reducing agents, conjugate redox pairs perform experiments to determine the order of metals in a reactivity series; compare predictions with results use a problem-based learning approach to investigate an issue in chemistry, for example source and effects of acid rain on living and non-living things, source and effects of ocean acidification on living things and the environment, affect of metal corrosion on marine and acidic environments, affect of the production of vast quantities of sulfuric acid as a result of extracting metals from sulfide ores fold a 4 cm x 4 cm sheet of copper foil into the shape of an envelope; wear eye protection and light a Bunsen burner; hold the copper envelope in tongs and heat strongly in the flame for 5 minutes; place the copper envelope on a heatproof mat to cool; open the envelope, compare the inside to the outside and record observations in your logbook; explain results in terms of oxidation; devise an experiment to show that the effects on the outside of the envelope were not due to carbon formation investigate the effects of the pH level of a solution on the corrosion of iron and copper; explore different methods of corrosion prevention when a layer of hot salt solution lies above a layer of cold water, the interface between the two layers becomes unstable and a structure resembling fingers develops in the fluid; investigate and explain this phenomenon

Detailed example HOW CAN HARD WATER BE SOFTENED? Aims To develop skills in hypothesis formulation related to the softening of hard water. To design, perform and analyse an experimental investigation related to the softening of hard water that involves generation of primary data. To effectively communicate investigation findings. Background information for teachers and students Water hardness relates to the concentration of certain minerals dissolved in the water, particularly calcium and magnesium, and to a lesser degree iron, manganese and barium. The scale used to determine water hardness ranges from ‘soft’ to ‘very hard’ as follows:

Water classification Hardness (mg L-1) Soft 0–60 Moderately hard 61–120 Hard 121–180 Very hard ≥181

Various recommendations have been made for the maximum and minimum levels of calcium (40–80 ppm) and magnesium (20–30 ppm) in drinking water, and a total hardness expressed as the sum of the calcium and magnesium concentrations of 2–4 mmol L-1.

© VCAA 2016 31 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Information related to measurements of water hardness in Australian cities, for example by the Australian Water Association www.awa.asn.au, shows a wide range of values:

Capital city Total hardness (calcium carbonate mg L-1) Adelaide 134–148 Brisbane 100 Canberra 40 Darwin 31 Hobart 5.8–34.4 Melbourne 10-26 Perth 29–226 Sydney 39.4–60.1

Hard water forms when water filters through limestone and chalk deposits, which are largely made up of calcium and magnesium carbonates. Although hard drinking water may have some health benefits it can also pose serious problems in industrial settings where it can impair the function of boilers, cooling towers and other equipment that involve water. In domestic settings hard water is often indicated by a lack of suds formation when soap is agitated in water and by the formation of limescale in kettles, water heaters and on the inside of bathtubs. In swimming pools hard water can have a turbid, or cloudy (milky) appearance. Hard water may affect soil quality leading to changes in growth of plants including crops. Hard water can be either ‘permanent’ hard water (water that contains calcium or magnesium salts other than the hydrogen carbonates) or ‘temporary’ hard water. Temporary hardness may be removed by boiling, but permanent hardness survives the boiling process. With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather, because the Ca2+ ions react with the stearate ions of the soap to form calcium stearate, a solid precipitate (the soap scum): - 2+ 2 C17H35COO (aq) + Ca (aq) → (C17H35COO)2Ca (s) The hardness of a water sample can therefore be measured in terms of its soap- consuming capacity. Water softening is commonly used to reduce hard water’s adverse effects in situations where water hardness is a concern. Lime (Ca(OH)2) and soda ash (Na2CO3) are commonly used to treat hard water. Synthetic detergents do not form soap scums in hard water. Topic selection phase The practical investigation enables teachers to work with students to develop hypotheses, design and perform experimental investigations that require generation of primary data and present investigation findings. Teachers must consider the management logistics of the investigation, taking into account number of students, available resources and student interest. The following questions require consideration: What input will students have into the selection of the investigation question? Will different groups of students in the class be able to undertake different investigations? To what extent will all students consider the same investigation question, or complete different parts to the same question so that class data can be pooled? What input will students have into the design of the experiment? In this detailed example, students were presented with the background information and used out-of-class time to undertake further internet research to consider available treatments of hard water. As a class, a methodology for testing water hardness was devised, based on the provided general definition of water hardness as being the soap- consuming capacity of a water sample. Students then worked in groups to propose a research question for investigation related to the softening of hard water. Sample student-generated research questions include:

© VCAA 2016 32 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Does pH affect water hardness? What is the effect of adding sodium carbonate crystals (washing soda) to different types of water samples (untreated deionised water, untreated tap water, untreated temporary hard water, untreated permanent hard water, boiled deionised water, boiled tap water, boiled temporary hard water, and boiled permanent hard water)? Does temporary hard water respond to the same treatments as permanent hard water? Alum is a complex compound of aluminium that can be used to remove clay from a water sample. Can it also be used to treat hard water and, if so, what concentrations are most effective? How effective are different concentrations of borax and washing soda in treating hard water? How is the proportion of calcium and magnesium in a water sample related to water hardness? Teacher notes

'Temporary' hard water can be made by decanting a saturated solution of Ca(OH)2.

‘Permanent’ hard water can be made by using either 1 g CaSO4•2H2O or 1 g MgSO4•7H2O in 100 mL water. Comparing samples for degree of hard water: Teachers could use or adapt the standard Clarke’s soap solution – devised by Dr Thomas Clarke, Professor of Chemistry at Aberdeen University, in 1843 – which involves finding out the volume of a soap solution of known concentration (for example 10 g of plain laundry soap per 100 mL of 80 % ethanol) required to form a permanent lather with a known volume of the water to be tested (for example 5 mL) in a test tube. Planning phase Students may need guidance in: fitting the investigation into the time available, and developing a work plan identifying the technical skills involved in the investigation, and ensuring that resources are available that meet the requirements of the investigation. Teachers should work with students to: discuss the independent, dependent and controlled variables in proposed experiments identify safety aspects associated with undertaking experiments related to hearing and sound establish the use of physical units of measurement and standard notation, and how to reference sources and provide appropriate acknowledgments. Teachers could provide students with a template that structures the investigation into a series of timed phases. The template may subsequently be adapted by students as a personal work plan in their logbooks. Investigation phase Student-designed methodologies must be approved by the teacher prior to students undertaking practical investigations. A possible schedule for management of the multiple investigations in the class is as follows: each student undertakes internet research, if required, to find background information related to the general topic for investigation students work individually or in groups to confirm a research question, formulate a hypothesis and propose a research methodology, including management of relevant safety and health issues teacher approval for the methodology is granted prior to students undertaking the investigation students perform investigations, record and analyse results and prepare final presentation of their findings using an agreed report format. Reporting phase Students consider the data collected, report on any errors or problems encountered, and

© VCAA 2016 33 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS use evidence to explain and answer the investigation question. Other avenues for further investigation may be developed following evaluation of their experimental design and quality of data. The above phases could be recorded in the student logbook. The report of the investigation can take various forms including a written report, a scientific poster or a multimedia or oral presentation of the investigation.

© VCAA 2016 34 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Area of Study 2: How are substances in water measured and analysed? Outcome 2: Examples of learning activities Measure amounts of use local examples of the management of chemical dissolved substances in contaminants in each of the categories of salts, organic water and analyse compounds and acids or bases water samples for salts, describe two sampling protocols and identify how they would organic compounds and contribute to accuracy, precision, replication and/or validity acids and bases. of water analysis results formulate hypotheses and design and perform investigations related to the following research questions: How do commercial brands of water differ from each other? How does bottled water differ from tap water? How does bottled water differ from filtered tap water? How is bottled water sanitised for human consumption? What are some practical ways to recycle plastic bottles? undertake a water quality analysis for samples of water, for example, combine laboratory ‘wet’ and instrumental techniques with online calculators such as that at the Water Research Centre in Dallas, Texas, USA at www.water- research.net/index.php/water-treatment/water- monitoring/monitoring-the-quality-of-surfacewaters, which calculates water quality based on nine indicators (in order of decreasing significance: dissolved oxygen, fecal coliform, pH, biochemical oxygen demand, temperature change, total phosphate, nitrates, turbidity, total solids) examine the ingredients list of chemicals and foods for which solution quantities are provided; convert between given units and alternate units of concentration, for example g L-1, mg L-1, %(m/m), %(m/v), %(v/v) design and perform an investigation to determine: the types of contaminants that alum can coagulate in water whether there are optimal amounts of alum that should be added to coagulate contaminants in water sample how effectively alum can inactivate microbes in a contaminated water sample explain why acids should be added to water, rather than adding water to acids, when diluting acids or when undertaking acid-base experiments perform dilutions of different solutions and calculate quantities at each dilution stage investigate the Law of Conservation of Mass by tracking mass changes occurring during chemical reactions in closed systems discuss principles and applications of gravimetric analysis perform a gravimetric analysis and use mass-mass stoichiometry to determine the mass of salt in a water sample; collate and compare class data to evaluate accuracy and precision; discuss whether performing repeated analyses improves accuracy and precision prepare a standard solution of anhydrous sodium carbonate

© VCAA 2016 35 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS and use it to standardise a solution of hydrochloric acid perform an acid-base titration and use volume-volume stoichiometry to calculate the concentration of an acid or base in a water sample discuss the principles of colorimetry including the relationship between concentration and absorption use secondary colorimetry data to construct a calibration curve and determine the concentration of an ingredient in a consumer product perform an instrumental analysis of a coloured species in solution, for example compare the phosphate content of various fertilisers or washing powders; investigate why phosphates pose problems in waterways and how these problems are resolved bottled water is sometimes fortified with various vitamins and nutrients: investigate and produce a short report to explain the purpose of the additives and how the amounts that are added are determined discuss the following quote by Thomas A. Edison in terms of analytical analysis: ‘Negative results are just what I want. They’re just as valuable to me as positive results. I can never find the thing that does the job best until I find the ones that don’t’ investigate the applicability of Benford’s Law, also called the first-digit law (in lists of numbers from many everyday sources of large datasets, the leading digit is distributed in a specific, predictable way: 1 = 30.1%, 2 = 17.6%, 3 = 12.5%, 4 = 9.7%, 5 = 7.9%, 6 = 6.7%, 7 = 5.8%, 8 = 5.1%, 9 = 4.6%), to chemical data, for example global water quality data such as those at: www.gemstat.org/ or data obtained from state or local water authorities design a regime for the rapid comparison of the total amount of dissolved solids in different water samples respond to a chemistry-based issue in society, for example ‘Would you drink recycled water?’

Detailed example RESPONDING TO A CHEMISTRY-BASED ISSUE IN SOCIETY: WOULD YOU DRINK RECYCLED WATER? Many contemporary issues in society involve chemistry ideas and concepts in addition to the consideration of personal and communal values. In this detailed example, the teacher used the question ‘Would you drink recycled water?’ as a summative learning task following learning activities related to measurements of solubility and concentrations, chemical analysis and a class excursion to a water treatment plant. The focus of this activity is on students being able to consider the nature of evidence, distinguish between facts and opinion, and synthesise arguments to communicate a response to a chemistry- related social issue. Aim To communicate a justified response to a social issue involving chemistry concepts through participation in a ‘Question & Answer’ panel discussion. Introduction © VCAA 2016 36 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Teachers could organise the class so that students work in groups to form a number of different Q&A panels where each student takes on the role of a different stakeholder, or use a jigsaw approach to create one class Q&A panel with each panelist having a team of ‘researchers’ to assist in the development of panel arguments. Students role-play a Q&A panel discussion to examine the arguments for and against using recycled water as a source of drinking water. Each student will assume the role of one stakeholder, or become part of the stakeholder’s research team, and become part of the panel discussion. Following the panel discussion each student provides an individual response to the question ‘Would you drink recycled water?’ by producing a public communication in an agreed format, for example newspaper article, infographic, or TV advertisement. The communication must include referenced qualitative and quantitative data, distinction between identified facts and opinions presented in the Q&A panel discussion and justified personal stance on the question. Science skills Teachers should identify and inform students of the relevant key science skills embedded in the task. Preparation Prior learning experiences related to water sampling techniques, measurement of solubility and concentration, and analytical techniques used to analyse for salts, organic compounds, and acids and bases Prior consideration of validity, facts and opinions, for example, students discussed sources of reliable information related to the following chemistry-based information: a. drinking water, also known as potable water or improved drinking water, is defined as water that is safe enough for drinking and food preparation b. globally, in 2012, 89% of people had access to water suitable for drinking. Students should have discussed examples of ‘effective’ and ‘ineffective’ oral and written communication techniques and practices. Students become panel members that represent stakeholder interests (students select the names of stakeholders at random ‘from a hat’), for example local resident with young family, mayor, local water authority representative, analytical chemist, site worker from company contracted to carry out water treatment, medical professional, local producer of carbonated water, meteorologist, and environmental activist. Students should have access to ‘fact sheets’ or authoritative sites related to water treatment and drinking water specifications, for example excerpts from the Australian Drinking Water Guidelines at www.nhmrc.gov.au/guidelines-publications/eh52; World Health Organization’s guidelines for drinking water quality at www.who.int/dwq/gdwq0506; comparison of drinking water standards around the world, such as found at www.safewater.org. Health, safety and ethical notes Students should be respectful of others and their opinions at all times. Students should be reminded that this activity is simply a role-play and the comments made do not necessary reflect the attitudes of the individual speakers. Procedure Lessons 1 and 2: In these lessons students consider general information about the process of treating water to make it potable, including statutory requirements for water to be classified as ‘drinkable’; put themselves in the role of one stakeholder and present their position; construct a question they would like addressed by a discussion panel; and prepare possible responses to these questions from their perspective as one stakeholder. Some time out of class may also be required for students to complete background research. Students: Read through the ‘fact sheets’ or websites relating to water treatment and water quality. Note in the logbook major points of interest. Select at random the name of a stakeholder relevant to the issue. Spend 10 minutes brainstorming the likely perspective of the stakeholder towards the issue. Students may discuss their ideas with peers and the teacher. Students need to © VCAA 2016 37 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS consider the biases (feelings, opinions, prejudices) that their stakeholder may have for this issue and write these into the logbook. Present a 20-second oral summary of the stakeholder to the class, for example: ‘My name is X and I am the mayor of this town where it is proposed that we supplement our drinking water supplies with treated water, since we often need to apply water restrictions due to low water reserves in our dam. The majority of my constituents are against the proposal since there are concerns that the treated water will still contain microbes or chemicals that may threaten human health and that treated water could never exactly replicate the quality of rain water or the water in our dams.’ On a slip of paper, construct one question that they would like addressed by someone relating to this case study. Students may suggest which stakeholder they would like to primarily respond to their question. The question should be well thought out so as to give as much insight into different perspectives in considering the issue. Students may use the following list of question terms to assist them – List 1: Who/What/Where/When/Why/How…? List 2: …would/could/should/is/are/might/will/was/were…? Submit the question to the teacher, who will collate (perhaps by photocopying all slips onto a single sheet of paper) and distribute them to the relevant discussion panel. Now working with the other members of the panel, discuss the questions that have been submitted and write notes into the logbook detailing the response to these questions from the perspective of a stakeholder. Include as much scientific data as possible in the responses. Students may need to conduct additional Internet research to develop responses. Lesson 3: In this lesson students role-play the perspective of one stakeholder as part of a panel discussion. They may use any notes already written in the logbook and may also make additional notes in the logbook during the class. Lesson 4: In this lesson students provide an individual response to the question ‘Would you drink recycled water?’ by producing a public communication in an agreed format, for example newspaper article, infographic or TV advertisement. By the end of the lesson they submit a draft of their response. They may use any notes from the logbook. The communication must include referenced qualitative and quantitative data, distinction between identified facts and opinions presented in the Q&A panel discussion and justified personal stance on the question. The media communication should identify / highlight the: a likely target audience specific scientific concept/s being communicated distinction between fact and opinion scientific data used to justify position of the stakeholder. Students will be assessed with respect to: accuracy of scientific information clarity of explanations appropriateness for purpose and audience.

Area of Study 3: Practical investigation Outcome 3: Examples of research questions Design and undertake a How effective are different sampling methods in the accurate quantitative laboratory analysis of the quantity of a substance that is dissolved in investigation related to water? water quality, and draw How are the specific heat capacities of different liquids affected conclusions based on by the addition of salts, acids, bases, oxidants or

© VCAA 2016 38 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS evidence from collected reductants? data. How are the conductivities of different liquids affected by the addition of salts, acids, bases, oxidants or reductants? Is solubility related to biodegradability? How does the solubility of a solute vary in fresh water as compared to sea water? Which ions are more important in determining the ‘hardness’ of water? How do different types of detergents perform in water of varying ‘hardness’? How does water quality differ at various points along a waterway or around a body of water? Is the pH of sea water affected in the same way as the pH of fresh water when acidic or basic substances are added to them? How are different types of shells/polymers/metals affected by different pH conditions? How does the rate of corrosion of different metals compare in salt and fresh water?

Detailed example HOW DOES WATER QUALITY DIFFER AT VARIOUS POINTS ALONG A RIVER? The practical investigation builds on knowledge and skills developed in Unit 2 Area of Study 1 and/or Unit 2 Area of Study 2. Teachers must consider the management logistics of the investigation, taking into account number of students, available resources and student interest. The following questions require consideration: What input will students have into the selection of the investigation question? Will different groups of students in the class be able to undertake different investigations? To what extent will all students consider the same investigation question, or complete different parts to the same question so that class data can be collated? What input will students have into the design of the experiment? Will off-school site work be involved? Teachers could provide students with a template that structures the investigation into a series of timed phases. The template may subsequently be adapted by students as a personal work plan in their logbooks. Topic selection phase In Unit 2 Area of Study 2, the teacher made use of the local river that ran through the town to explore concepts related to identifying and measuring different substances in water. In this detailed example, a general class investigation question was generated following student interest in exploring factors that affected the river’s water quality. In a class discussion following Unit 2 Area of Study 2 activities where students measured the pH and total dissolved solids of river water samples, students wondered whether their results would have been different if they had performed the experiments at different times of the day or in different seasons of the year. They discussed the different environment conditions at various points in the river, such as shaded or exposed sites, and treed versus cleared areas. One environmentally conscious student noted that a public picnic ground abutted the river and that paper, plastic and food scraps often ended up in the river. Another student referred to sections of the river allocated to swimming and boating activities and wondered whether factors such as body oils and turbulence affected water quality. From this discussion students formulated a number of

© VCAA 2016 39 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS research questions for investigation, based on a general question: How does water quality differ at various points along a river? Sample student-generated research questions include: What chemical categories of rubbish are dumped into the river and how is water quality affected? How do recreational activities such as swimming and fishing affect water quality? Does exposure to sunlight affect the pH of water? Does exposure to sunlight affect the solubility of salts in water? Do overhanging trees change the chemical composition of the water? Is the proportion of chemicals in faster-running parts of the river different from the proportion of chemicals in slower-running parts of the river? Is the proportion of chemicals in deeper parts of the river different from the proportion of chemicals in shallower parts of the river? Planning phase Students may need guidance in: formulating a testable hypothesis fitting the investigation into the time available, and developing a work plan identifying the technical skills involved in the investigation, and ensuring that resources are available that meet the requirements of the investigation. Teachers should work with students to: determine to what extent students will work independently or in groups in undertaking the experiment (for example, different students or groups may investigate different aspects of river quality; all students may investigate a selected question and work at different sites along the river to collect and collate data; a limited number of questions may be self-selected for investigation by students) discuss the independent, dependent and controlled variables in proposed experiments determine the types of quantitative experiments that will be performed, for example titrations, solubility tests, instrumental analysis identify safety aspects associated with undertaking experiments in the field and in the laboratory, and in working with chemicals and apparatus establish the use of physical units of measurement and standard notation determine the nature of the communication: Who would be interested in the results of students' investigations? What would be the most effective way to communicate results to an interested audience? Investigation phase Student-designed methodologies must be approved by the teacher prior to students undertaking practical investigations. A possible schedule for management of the multiple investigations in the class is as follows: each student undertakes internet research to find background information related to the general topic for investigation students work individually or in groups to confirm a research question, formulate a hypothesis and propose a research methodology, including management of relevant safety and health issues teacher approval for the methodology is granted prior to students undertaking the investigation time is allocated for water sample collection in the field if required, time is allocated to access equipment/instrumentation out-of-school students perform investigations, record and analyse results and prepare final presentation of their findings using an agreed report format. Reporting phase Students consider the data collected, report on any errors or problems encountered, and

© VCAA 2016 40 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS use evidence to explain and answer the investigation question. Other avenues for further investigation may be developed following evaluation of their experimental design and quality of data. Students may work individually or in groups. The above phases could be recorded in the student logbook. The report of the investigation can take various forms including a written report, a scientific poster or a multimedia or oral presentation of the investigation.

Unit 3: How can chemical processes be designed to optimise efficiency?

This unit focuses on energy production and use, and the rate and extent of chemical reactions. Practical activities should not be limited to assessment tasks; they may be used to introduce a chemical concept, to build understanding of a chemical concept or skill and to practise specific scientific skills, for example, experimental determination of ΔH, construction of galvanic, electrolytic and fuel cells, changing equilibrium position, and use of Faraday’s Laws. Area of Study 1: What are the options for energy production? Outcome 1: Examples of learning activities Compare fuels  view real or virtual displays of fuel samples, for example, quantitatively with coal, crude oil, kerosene, paraffin oil, candles, peanut oil, reference to biodiesel, bioethanol, wood; predict melting points and combustion products boiling points based on the physical states of each sample; and energy outputs, compare predictions with experimentally determined or apply knowledge of the accepted values from chemical databases electrochemical series to design, construct and  use the Internet and other sources to investigate and test galvanic cells, and compare the use, renewability and environmental impact of evaluate energy the sourcing and combustion of a selected fossil fuel and a resources based on selected biofuel energy source; compare class findings to energy efficiency, discuss whether there is a clear case for the use of a biofuel renewability and in preference to a fossil fuel environmental impact.  observe a burning candle and note all observations in logbook (thirty observations is achievable); access education.net/modules/scimath/faraday.htm or http://engineerguy.com/faraday/ and undertake activities that develop skills in making observations, and generating questions from observations; discuss the importance of careful observation in science, referring to recent practical investigations  compare heats of combustion of various fuels  access Sankey diagrams (for example www.bbc.co.uk/schools/gcsebitesize/science/ aqa/energyefficiency/ energytransfersrev3.shtml ) and other representations of the energy transformation occurring in a combustion reaction to show why the combustion of fuels cannot be 100 per cent efficient; comment on the use of Sankey diagrams versus pie charts as representations of energy efficiency  use information from secondary sources to summarise the processes involved in the industrial production of ethanol from sugar cane; debate whether sugar cane is better used primarily for producing a region’s food or fuel supply  capture photos or images of a rapidly occurring chemical phenomenon related to energy production; use the images and add text to produce a photoessay or infographic of the phenomenon  design a flow chart or other representations to show unit conversions for and relationships between pressure, volume and temperature of gases

© VCAA 2016 42 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS  investigate the products of the complete and incomplete combustion of a fuel  explain why holding an inverted white evaporating dish above a yellow Bunsen burner flame produces black soot under the dish  use a gas syringe to collect and measure the gas evolved in a chemical reaction; plot your results as a volume-time graph  determine the relationship between P and V when the pressure on a gas sealed in a syringe is increased  investigate the heat of combustion of ethanol, including determination of the energy efficiency of the combustion using data from a data table and identification of sources of energy loss through energy transformation and energy transfer  complete stoichiometric exercises requiring the calculation of a combination of an amount of solids, liquids, gases, solution concentrations or volume and the volume, temperature and pressure of gases (including consideration of quantities in excess in chemical reactions)  determine experimentally the heat of combustion of ethanol (different fuels may be used in the class) by placing fuel in a spirit burner, measuring heat and mass differences when heating a known quantity of water and using the specific heat capacity of water for calculations; compare experimentally determined values with published values for heat of combustion; compare heats of combustion of different fuels; suggest improvements to the experimental methodology  compare the advantages and disadvantages of the use of fossil fuels and biofuels as energy sources, for example: http://greenliving.lovetoknow.com/Advantages_and_Disadva ntages _of_Non_Renewable_Energy  create a blog to evaluate public arguments for the use of biofuels as a replacement for fossil fuels, for example consider arguments for the future of biofuels at www.eniday.com/en/technology_en/the-future-of-biofuels/ or http://auto.howstuffworks.com/fuel-efficiency/biofuels or www.washingtonpost.com/wp- dyn/content/article/2008/02/26/ AR2008022602827.html  construct models or create images of typical molecules present in petrodiesel and biodiesel  discuss the difficulties in quantifying the term ‘renewability’ in relation to its definition as ‘the ability of a resource to be replaced by natural processes within a relatively short period of time’; suggest how ‘a relatively short period of time’ could be quantified  explain differences in renewability of crude oil and biodiesel  research and outline the advantages and disadvantages of the use of bioethanol as an alternative car fuel, explain why it can be called a renewable resource and evaluate the success of current usage  discuss whether biodiesel is a ‘green’ fuel or a ‘red herring’ © VCAA 2016 43 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS  research the constitution of available fuel blends (for example, E10) for motorists and summarise the advantages and disadvantages of using 100% petrol versus a mixture of petrol and other fuels  undertake a web-based investigation related to the production of biodiesel using algae as the source of oil to summarise its current potential and challenges; present an argument as to whether this area of research is justifiably supported  compare the viscosity of liquid fuels at different temperatures  design apparatus or a technique for measuring and comparing the viscosities of liquid fuels  design, construct and test a small-scale biogas generator  identify ‘facts’ and ‘fiction’ contained in media articles reporting a local, global or international issue related to energy options  observe metal displacement reactions under stereomicroscopes; identify the products, oxidising and reducing agents, and conjugate pairs; write balanced chemical equations, including states, for observed reactions  determine the relative strengths of reducing agents and oxidising agents using metal displacement reactions; construct and test simple galvanic cells based on the findings  construct simple galvanic cells and explain in general principles their operation in terms of reactions occurring at the electrodes and the movement of electrons and ions (the focus is on the application of general principles rather than details for specific cells)  capture photos or images of the progress of a galvanic cell; use the images and add text to produce a photo essay or infographic of the progress of the reaction, identifying products formed and writing half and overall equations for the redox reactions involved  use the electrochemical series to design, set up and test a galvanic cell that can deliver a particular cell voltage; compare predicted with experimentally determined cell voltages; draw an annotated diagram of the cell and identify its key features; write and annotate equations for the relevant half-cell and overall cell reactions  investigate whether there is a relationship between the temperature rise in direct metal displacement reactions and the voltage of the galvanic cells driven by those reactions  predict how temperature will change over time in the bulk of the liquid in a metal displacement reaction, for example in the reaction between zinc and copper(II) chloride; use a temperature sensor to monitor the temperature change in the reaction over time and explain any differences between predicted and experimental results  work in a small group to produce an instructive multimodal clip to show the step-by-step construction and operation of a simple laboratory galvanic cell, including the use of a © VCAA 2016 44 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS galvanometer to determine direction of electron flow  use the electrochemical series to predict the outcome of competing electrode reactions in galvanic cells; design and perform experiments to test predictions; identify the limitations of the use of the electrochemical series in predicting electrode reactions  design a flow chart or other representation to compare the energy transformations occurring in a metal displacement reaction when the reactants are in direct contact and when they are separated in a galvanic cell  research and prepare a short report on the operation of a contemporary galvanic cell that has been designed for a specific purpose  analyse secondary data on the use of hydrogen as a fuel  design a poster showing the operation of a fuel cell  create a simple fuel cell and measure its voltage output; draw an annotated diagram of the cell, identifying its key features and annotate equations for the cell processes  create an animation of the cell processes in a typical galvanic cell and/or a typical fuel cell, including at the particle level  design a flow chart or other representation to compare the operation of fuel cells, the operation of galvanic cells and the combustion of fuels  use the internet to investigate developments and applications of fuel cell technology; compare the advantages and disadvantageous of fuel cells with other energy sources Detailed example IS THERE A RELATIONSHIP BETWEEN THE TEMPERATURE RISE IN DIRECT METAL DISPLACEMENT REACTIONS AND THE VOLTAGE OF THE GALVANIC CELLS DRIVEN BY THOSE REACTIONS? Introduction A systematic investigation of direct metal displacement reactions can be used to establish or to confirm an electrochemical series. Exothermic metal displacement reactions can be used to drive galvanic cells, in which the energy released in the reaction is in the form of electrical energy instead of heat energy. Students should record a justified prediction of the metal displacement reactions that should be observed in their logbooks prior to undertaking the experimental investigation. The temperature rise that occurs in metal displacement reactions, which is directly proportional to the heat energy released, is determined by using a temperature probe. The voltage across the galvanic cells driven by those reactions is measured using a voltmeter connected in parallel with each cell. The voltage is directly proportional to the electrical energy delivered by the cell per second by the relationship. Required: relevant glassware, equipment and materials including a voltmeter, a globe, electrical wiring, a temperature probe, strips of zinc, copper, iron and tin, strips of filter paper and solutions of 1.0 M ZnCl2, 1.0 M CuCl2, 1.0 M FeCl2, 1.0 M SnCl2 and 0.1 M NaCl (for salt bridges). Science skills Teachers should identify and inform students of the relevant science skills embedded in

© VCAA 2016 45 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS the task. Health and safety notes Students must: dispose of metal strips and metal solutions in properly labelled waste containers and not down sinks. wash their hands after handling the chemicals. Method Students: place a metal strip in a test tube with a temperature probe, add 20 mL of a 1.0 M solution of one of the test metals, and measure and record the temperature rise that occurs over 5 minutes. They also record their observations of any reaction that they observe over that time. This is repeated for a range of combinations of metals and metal solutions and the results compared with their predictions using the electrochemical series. set up galvanic cells, each using one of the metal displacement reactions that are identified as exothermic, and placing the same globe across the two electrodes. They measure and record the voltage across each cell. Discussion questions and report writing in logbook Students complete a results table showing the temperature rise and voltage for each metal combination. They then draw a scatterplot graph of voltage against temperature rise from all the data points to test if there is a relationship between the temperature rise and the voltage. Questions should focus on identification of the dependent and independent variables, controlled variables, sources of error and the validity of this experimental method and how it could be improved. Teacher notes This is a systematic procedure producing quantitative and qualitative data. Students should be aware that the experiment is not being conducted at standard conditions, as the temperature is not being held constant at 25 C, and the metal strips are not made from the pure metal. Extensions to this activity may involve students testing other metals, or processing the class results, to create more data points for the scatterplot graph.

Area of Study 2: How can the yield of a chemical product be optimised? Outcome 2: Examples of learning activities Apply rate and discuss and model the concept that chemical reactions equilibrium principles to involve the breaking and making of bonds predict how the rate and extent of reactions can revise kinetic molecular theory; create an animation or be optimised, and develop an analogy to illustrate collision theory explain how electrolysis demonstrate that the rate of reaction depends on frequency is involved in the of collisions using reaction between lead(II) nitrate and production of chemicals potassium iodide in the solid and aqueous states and in the recharging of explain how increasing temperature of a sample of gas or batteries. changing the molecular mass of a sample of gas affects Boltzman distributions distinguish between the terms ‘exothermic’ and ‘endothermic’; identify useful endothermic and exothermic reactions in everyday life produce a visual communication that illustrates how a heat pack or a cold pack works measure and record temperature changes over time for an exothermic and an endothermic chemical reaction using both a data logger and a thermometer; compare and discuss how accuracy, precision, replication and validity are affected when a data logger, rather than a thermometer, is used; identify situations where a data logger is more appropriate to use than a thermometer; identify situations where a thermometer is more appropriate to use than a data logger use data to explain the effect of changing pressure on the rate of a gaseous reaction conduct a laboratory investigation on the effect of temperature, solution concentration and surface area on the rate of reaction; predict outcomes of investigations based on kinetic molecular theory and/or Boltzman distributions; calculate reaction rates by determining the gradient of a graph of an amount of product produced versus time graph (or mass loss over time graph) and plot a graph of reaction rate versus time; explain observations in terms of the distribution of kinetic energies at different temperatures investigate quantitatively the effect of a catalyst on the rate of a chemical reaction illustrate the concept of activation energy using energy profile diagrams for catalysed and uncatalysed endothermic and exothermic reactions observe fast and slow chemical reactions; identify everyday situations where fast and slow reactions are desirable conduct a laboratory investigation related to the reversible nature of reactions, for example, the hydration and dehydration of copper(II) sulfate (www.rsc.org/learn- chemistry/resource/res00000437/a-reversible-reaction-of- hydrated-copper-ii-sulfate/); an equilibrium reaction involving copper(II) ions (www.rsc.org/learn-

© VCAA 2016 47 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS chemistry/resource/res00001711/an-equilibrium- involving-copper-ii-ions/); or the equilibrium involving carbon dioxide in aqueous solution (www.rsc.org/learn- chemistry/resource/res00001728/ equilibria-involving- carbon-dioxide-in-aqueous-solution/) interpret evidence for the dynamic nature of equilibrium explain why some chemical reactions are reversible and others are not; provide examples of reversible and irreversible reactions, including appropriate chemical equations and ‘product arrow’ notation draw a cartoon strip or create an animation to show what happens in a closed equilibrium system at the particle level predict and test the effect of changes to homogeneous equilibrium systems; represent findings using concentration-time graphs conduct a laboratory investigation of the effect of changing concentration on equilibrium position; demonstrate the effect of changing pressure and temperature on an equilibrium system use a spreadsheet to manipulate data to illustrate the

constancy of Kc at constant temperature perform calculations based on the equilibrium law, reaction

concentrations and Kc capture photos or images of the progression of an equilibrium reaction subject to temperature or pressure changes that is detectable by a colour change; use the images and add text to produce a photo essay or infographic of the phenomenon, including identification of the direction of the equilibrium shift use Le Chatelier’s principle to make predictions about changes (concentration, temperature, pressure) made to a system at equilibrium; experimentally confirm or refute predictions examine a case study of accidental carbon monoxide poisoning, for example people lighting a fire in a confined space such as a room or caravan with no ventilation; write equations to represent how the poisoning occurred; use Le Chatelier’s principle to explain how carbon monoxide poisoning can be treated create an animation of the processes occurring in a typical electrolytic cell, including at the particle level predict and test the products of electrolysis of aqueous solutions; use image capture to illustrate and annotate a cell diagram; write balanced chemical equations for the reactions, including states construct a simple electrolytic cell to identify factors that determine the products of electrolysis view an animation of the processes occurring in a smelter where a metal is extracted from its ore by electrolysis and explain what is occurring at the particle level, including use of the terms ‘oxidation’, ‘reduction’, ‘oxidising agent’, ‘reducing agent’, ‘cathode’, ‘anode’ and ‘electron

© VCAA 2016 48 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS transfer’ analyse the production of magnesium by electrolysis research Humphrey Davy’s discovery of many Group 1 and Group 2 metals by electrolysis of their molten salts and explain how this led to development of processes for extraction of aluminium and other highly reactive metals from their molten ores analyse data showing the relationship between amount of metal deposited in an electrolytic cell and charge flowing through the cell use the electrochemical series to predict the products of the electrolysis of potassium iodide solution; determine experimentally the products and account for any differences between predictions and results use Faraday’s laws in quantitative calculations related to electrolysis design and conduct an investigation to determine the percentage efficiency of electroplating an electrode or a metal object with copper research and explain the difference between electroplating and electrowinning as electrolytic processes design a flow chart or other representation to compare the operation of electrolytic cells with that of galvanic cells explain why some batteries are rechargeable while others are not; annotate a cross-section of a non-rechargeable battery to identify design features that could be changed to make the battery rechargeable draw simplified diagrams to explain how a rechargeable battery works, including half and overall cell reactions, for example nickel-cadmium, nickel-metal hydride, lead acid, lithium ion, or lithium polymer construct a simple lead-acid accumulator (for example, www.rsc.org/learn- chemistry/resource/res00000391/rechargeable-cell-the- lead-acid-accumulator?cmpid=CMP00005907); suggest how to test for factors that affect the operation of the battery take a ‘battery quiz’ to review principles of the operation of a rechargeable battery or to review battery applications (for example, http://environment.nationalgeographic.com.au/environme nt/energy/great-energy-challenge/battery-quiz/) research and investigate the general principles behind the operation of a contemporary rechargeable cell

Detailed example ANALYSIS OF THE PRODUCTION OF MAGNESIUM BY ELECTROLYSIS Introduction Magnesium is a widely used metal that is highly reactive and therefore only occurs in nature in its compound form. Because it is so highly reactive, a large amount of energy is required to extract it from its compounds and the process must be very carefully controlled to prevent its re-oxidation. This is why electrolysis of molten magnesium © VCAA 2016 49 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS chloride is a principal method of extracting magnesium. The design of this electrolytic process is critical to it being energy-efficient and economically viable. Teaching note Detailed outlines of the commercial extraction of magnesium from molten magnesium chloride may be readily obtained from a variety of internet sources Aim and method Students work individually or in pairs to analyse a detailed outline of the commercial extraction of magnesium from molten magnesium chloride to explain the purpose of its design features, and to design a flow chart to represent the process, including its by- products, and waste materials. Students may be guided by a series of questions on the important factors in the design of this process so that it is energy-efficient and economically viable. These factors include:  use of a molten, rather than aqueous, electrolyte  control of temperature of the molten electrolyte and how the energy required for this is supplied  purity of the electrolyte – and whether any other metal compound can be present and for what purpose  materials used for the electrodes and why they are suitable  prevention of unwanted side-reactions  use of any separating devices  physical design of the cell to increase its energy-efficiency  use of different densities of the molten electrolyte and products  removal and storage of the magnesium and other products when formed, and the role of the different densities of the reactants and products in facilitating this. Discussion questions and recording in logbook A series of questions may be set as a post-activity for students to answer in their logbook, for example:  Compare: Silver and gold and some copper can be found in nature as the metal. What is the trend in the ease of extraction of a metal from its compound as you go down the electrochemical series?  Identify: Name three metals that could be extracted by electrolysis of an aqueous solution of their compound and three metals that could only be extracted by electrolysis of their molten compound.  Apply: Would it matter if some magnesium chloride impurity were present in the electrolyte when sodium is extracted from its compound in an electrolytic cell? Justify your answer.  Infer: Which metal on the electrochemical series would require the most electrical energy to extract it from its compound by electrolysis? What can be inferred about the design of this electrolytic cell in terms of materials that might be suitable for the electrodes and how the product of the reaction might be separated, removed and stored?  Create: Create a graphic organiser or computer simulation to summarise the process of extracting a metal from its ore by electrolysis, including the energy transformations involved.

Unit 4: How are organic compounds categorised, analysed and used?

This unit focuses on the structures, nomenclature and reactions of organic compounds including a detailed study of the chemistry of major food groups and components. Practical activities should not be limited to assessment tasks; they may be used to introduce a chemical concept, to build understanding of a chemical concept or skill and to practise specific scientific skills, for example, modelling of organic structures, synthesis of organic compounds, instrumental analysis, acid-base and redox titrations, and calorimetry. Area of Study 1: How can the diversity of carbon compounds be explained and categorised? Outcome 1: Examples of learning activities Compare the construct models or other representations of structures of: general structures and reactions of hydrocarbons the major organic haloalkanes, alcohols, carboxylic acids and primary amines families of structural isomers and stereoisomers (including optical isomers) compounds, primary amides, aldehydes and ketones deduce structures of organic non-branched esters compounds using prepare a summary sheet or flow chart outlining the rules for naming instrumental organic compounds analysis data, and take a chemistry quiz related to organic nomenclature, for example design reaction Quizzes 1 and 3 at www.chemistry.uoguelph.ca/educmat/ pathways for the %20chm19104/%20%20organic_%20nomenclature_quizzes.htm synthesis of organic molecules. undertake a think-pair-share exercise where each member of the pair creates and names a series of isomers of an organic molecule based on hexane (1st member of the pair) or heptane (2nd member of the pair) with the addition of no more than three functional groups; critique each other’s structures and nomenclature research the properties of L-glucose and D-glucose; produce a summary table of similarities and differences use an inquiry approach to explore a case study in chemistry: thalidomide research the labelling of hazardous materials; identify safety procedures to be followed when handling specific chemicals determine experimentally the boiling point of isopropyl alcohol and the melting point of powdered acetamide; conduct a safety audit prior to undertaking the investigations determine experimentally the trend in boiling points of a series of organic compounds; conduct a safety audit prior to undertaking the investigation compare the viscosity of different liquids by inverting sealed tubes with different liquids and measuring time taken for an air bubble to reach the surface; design and conduct a different experiment to test the viscosity of liquids design and annotate flow charts to represent reaction pathways for particular organic syntheses synthesise an ester; write balanced chemical reaction including reagents and reaction conditions; construct a flow chart to show © VCAA 2016 51 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS the production of esters from alkenes determine quantitatively the percentage yield and atom economy of an organic reaction, for example http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2 011/%20chemcalc/chemcalc_higherrev5.shtml; discuss whether percentage yield or atom economy is more important in ‘green’ chemistry, for example http://www.rsc.org/Education/Teachers/Resources/Inspirational/re sources/6.6.1.pdf discuss the role of chemical analysis in determining the quality of consumer products examine a case study of the analysis of an unknown compound, for example food poisoning, drug detection, metal contamination discuss the relationship between the properties of a chemical under investigation and different analytical techniques discuss the principles and applications of atomic absorption spectroscopy use secondary atomic absorption spectroscopy data to determine, for example, the iron content in waste water storage ponds research the principles of mass spectroscopy and interpretation of mass spectrographs of atoms and molecules discuss principles and application of infrared spectroscopy, and interpretation of simple IR spectrographs discuss principles and application of proton and carbon-13 NMR and interpret some simple proton and carbon-13 NMR spectrographs in determining the composition and structure of an unknown compound predict the spectra of given organic compounds suggest a method for estimating the concentration of spirits (pure or diluted with water) in a closed bottle without opening the bottle compare class measurements of the length of a specified object and use the results to discuss the difference between the terms ‘accuracy’ and ‘precision’; determine the maximum precision of length measurement with a steel ruler compared with a wooden ruler; discuss the importance of accuracy and precision in analytical chemistry discuss general principles and applications of chromatography describe qualitatively and quantitatively what happens when a drop of coloured liquid is placed on a piece of absorbent paper; compare this phenomenon with the principles of HPLC create an animation or other visual representation to illustrate how an HPLC column works at the particle level use data from a number of analytical techniques to determine the identity of a compound complete exercises involving the identification of an appropriate analytic technique for a specified purpose arrange a site tour of an analytical laboratory to observe chemical instrumentation at work; process sample data review stoichiometry including balancing equations determine the concentration of an organic compound in an aqueous solution

© VCAA 2016 52 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS discuss criteria for selection of primary standards prepare a standard solution and use this to find the concentration of an acid or base of unknown concentration practice the use of volumetric equipment and discuss their accuracy distinguish between the equivalence and end point of a reaction; evaluate the strengths and limitations of volumetric analysis carry out volumetric analysis (direct titration) of acid/base content of consumer products, for example acid content of vinegar, white wine or fruit juices; carbon dioxide content of fizzy drinks; carbonate content of health salts solve quantitative exercises involving acid-base reactions; use volume, concentration and mass of reactants perform redox titrations to determine quantities of specific organic substances in consumer products, for example alcohol in white wine, Vitamin C in fruits determine the maximum precision of length measurement with a steel ruler; discuss the significance of precision in measurements of chemistry-based phenomena; use examples to illustrate the effect of variable precision on the results of calculation related to volumetric analysis construct a summary table of various volumetric, chromatographic and spectroscopic techniques (include properties at the atomic or molecular level of the substance under investigation on which the technique is based, and examples of uses)

Detailed example PREDICTING THE SPECTRA OF GIVEN ORGANIC COMPOUNDS Introduction Mass spectrometry, infra-red (IR) spectroscopy and proton and carbon-13 nuclear magnetic resonance (NMR) spectroscopy each provide unique information about the structure of an organic compound, enabling that structure to be deduced. Conversely, if the structural formula of an organic compound is already known, then the m/z value of its molecular ion peak on its mass spectrum, key features of its NMR spectra, as well as some key absorption bands on its IR spectrum, can be predicted, using the same principles. Aim and method Students work individually or in pairs on this task. They use a data book to assist in this task. Students may be: given the semi-structural formulas of butanal, CH3CH2CH2CHO, and butan-2-one, CH3COCH2CH3, and asked to draw their structural formulas (naming of the aldehydes and ketones is not required) asked to determine the m/z value of the molecular ion peak for each compound; teachers should establish that the two compounds are structural isomers through questioning/class discussion asked to identify the key bonds present in each molecule that would be detected in their infrared spectra and at what wave numbers the corresponding key bands would be located in their spectra provided with two pairs of axes to predict and sketch the high resolution proton NMR spectrum for each compound; the relative peak heights as well as the number of peaks and their location should be shown; students may then be asked whether this is sufficient to distinguish between the two compounds asked to predict the number of peaks that would be observed in the carbon-13 NMR spectrum of each compound given copies of the MS, IR and proton and carbon-13 NMR spectra to evaluate their predictions and to analyse the reasons for any errors they made. Discussion questions and recording in logbook A series of questions may be set as a pre-activity for students to answer in their logbook, for example: Understanding: Why does an organic molecule produce a range of peaks when it is analysed by a mass spectrometer? What determines their m/z value? Predicting: If an organic molecule is an ester, what are two bonds present in the molecule that will produce a characteristic absorption band on its IR spectrum and at what wave numbers should those bands be located?

Applying: For the molecule CH3CH2CH(OH)CH3, how many different hydrogen environments and how many different carbon environments are present? Hence, how many peaks will be present on the low-resolution proton NMR spectrum and carbon-13 NMR spectrum of this compound? What will be the resulting splitting pattern on the high-resolution proton

© VCAA 2016 53 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS NMR spectrum? Teaching notes Teachers may access the free site Spectral Database for Organic Compounds (SDBS) to obtain the actual spectra for butanal and butan-2-one at bin/cre_index.cgi

Area of Study 2: What is the chemistry of food? Outcome 2: Examples of learning activities Distinguish between the chemical structures of key food molecules, analyse the chemical  use molecular model kits, computer simulations or other multimedia resources to reactions involved in the metabolism of the major components of food including the role describe the composition and generalised structure of proteins as polymers of amino of enzymes, and calculate the energy content of food using calorimetry. acids  use a paper streamer to model and distinguish between the primary, secondary, tertiary and quaternary structures of proteins, for example, haemoglobin; view animations of the structure and function of haemoglobin  identify the type of bonding involved in maintaining the primary, secondary and tertiary structure of proteins; distinguish between denaturation of a protein and hydrolysis of its primary structure  use a data table of amino acids to model the molecular structures of 2-amino acids, their condensation reactions and peptide links  prepare a sample of nylon in the laboratory and extract a protein from food (for example, casein from milk); compare the structure of nylon with that of a protein  identify the functional groups present in monosaccharides; write equations to show how monosaccharides condense to form disaccharides and polysaccharides  model the ring structures of two D-glucose molecules, the condensation reaction between them and the glycosidic bond that is subsequently formed  model the structures of glucose, fructose, sucrose and aspartame; relate their properties to their structures  design and perform an experiment to determine whether ants have a preference for: natural versus artificial sweeteners; solid or liquid sweeteners; sucrose versus either of its two monomers  perform an experiment to determine the energy content of sugars  investigate the properties of carbohydrates, for example http://course1.winona.edu/tnalli/spring05/209labs/expt6.pdf  research the structure and chemical reactions involved in the synthesis and hydrolysis of glycogen, for example practice/physical-sciences-practice-tut/e/the-structure-and-function-of-glycogen-  identify the repeating unit of a biopolymer given the structural formula of a section of a chain  identify the functional groups present in glycerol and a range of fatty acids; write equations to show how these molecules condense to form fats/oils  model the structures of fats and oils and fatty acids, including omega-3 fatty acids and omega-6 fatty acids; relate their properties to their structures  perform a titration to determine degree of saturation of fats and oils, for example www.rsc.org/learn-chemistry/resource/res00000394/unsaturation-in-fats-and-oils? cmpid=CMP00005977  access reports of the analysis and/or ranking of fats and oils from the internet and compare stated values for percentage monounsaturated, polyunsaturated and saturated fats, smoking points, proportion of omega-3 to omega-6 fatty acids and © VCAA 2016 54 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS other points of interest; discuss how differences in reported values may arise; establish criteria for ranking the nutritional value of fats and oils; construct a ‘fact and fiction’ file related to information about fats and oils (for example https://health.clevelandclinic.org/2014/10/heart-healthy-cooking-oils- 101;%20www.prevention.com/eatclean/best-cooking-oils www.prevention.com/eatclean/best-cooking-oils www.livestrong.com/slideshow/1011176-pros-cons-16-types-cooking-fats-oils-top-picks/  compare the structure and functional groups present in a range of vitamins; predict their solubilities in water and fats/oils based on their chemical structures; investigate experimentally their solubilities and compare predictions and experimental findings to published values for solubilities  collect food labels and compare types of carbohydrates, fats/oils and vitamins; produce models of the different food components and classify into water-soluble/water- insoluble and essential/non-essential dietary components  explain the chemical relationship between food and energy  draw structures and write reactions to show and compare the hydrolysis reactions of fats and oils, proteins and starch  design and annotate flow charts to represent the breakdown of food through hydrolysis reactions in the digestive tract and the building up of new molecules through condensation reactions in cells  identify the components of a selected processed food and write reactions for their hydrolysis; explain how the products of hydrolysis can be utilised to form different compounds  model the ‘lock and key’ and ‘induced fit’ mechanisms of enzyme action; discuss their significance in the functioning of enzymes in biochemical reactions  create an animation of the action of an enzyme in a biochemical reaction at the molecular level  investigate experimentally the effect of changes in pH and temperature on the reaction of an enzyme; use the available evidence to relate this to possible changes in the primary, secondary and/or tertiary structure of the enzyme involved  investigate experimentally the time taken for different enzymes to catalyse a reaction (www.nuffieldfoundation.org/practical-biology/factors-affecting-enzyme%20-activity and calculate reaction rates; produce reaction rate vs time, temperature or pH as appropriate for the following experiments: adsorb microscale quantities of plant extract onto filter paper discs and assess catalase activity by comparing times taken for the discs to surface in hydrogen peroxide use catalase in pureed potato to investigate the effect of changing hydrogen peroxide concentration on the rate of production of oxygen measure the effect of changing temperature on the time taken for lipase to break down the fats in milk to form fatty acids and glycerol measure the time taken for amylase to completely break down a sample of starch under different pH conditions measure the time taken for different concentrations of trypsin to digest the gelatine coating on exposed photographic film and release the blackened silver halide  devise and conduct experiments to investigate the effects of temperature, pH, enzyme concentration and/or substrate concentration in reactions involving the hydrolysis of foods by enzymes, for example the action of: bromelain (enzymes in pineapples) on protein; trypsin on casein; amylase on starch; lipase on milk fat; pepsin on albumin; use different combinations of enzyme and substrate to investigate the specificity of enzymes

© VCAA 2016 55 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS  investigate the degree of denaturation (caused by the copper ions breaking down the tertiary structure of the albumin in egg white) of egg white by adding varying concentrations (for example, 0.002 M to 0.01 M) of copper (II) sulfate solution; centrifuge the solutions after denaturation to quantify the degree of denaturation; explain why copper bowls are often used in stabilising egg foams  identify cellulose as an example of a condensation polymer found as a major component of biomass and discuss its potential as a fuel  collate a media file of items related to a food chemistry issue (for example, ‘good’ and ‘bad’ carbohydrates/fats, GI foods, trans fats labelling); identify the chemical concepts involved and provide a critique of the items  design a one-page pamphlet to explain the chemistry of a biochemical phenomenon, for example lactose intolerance or the recommendation of low GI foods for diabetics  analyse and evaluate the usefulness and validity of the glycemic index (GI)  provide explanations for the following observations related to the glycemic index (GI): the longer pasta is cooked, the higher will be its GI the GI of bananas increases as they ripen the GI of different fruits and vegetables varies dependent on where they are grown  examine packets of oily or fatty foods and their use-by-dates; identify antioxidants in their lists of ingredients and the storage conditions for the food; determine whether there is a relationship between the type of fat and the degree to which the food may go ‘off’  tabulate the similarities and differences between enzymes and co-enzymes  view an animation of the action of a co-enzyme in a biochemical reaction at the molecular level; create a simplified flowchart to summarise chemical processes, for example the B vitamins http://highered.mheducation.com/sites/0072507470/student_view0 /chapter25/animation__b_vitamins.html  compare energy values of carbohydrates, proteins, fats and oils; analyse the energy content of a range of processed foods  write a balanced thermochemical equation for cellular respiration  plan and perform an experiment to demonstrate the fermentation of glucose under different temperature conditions, monitoring reaction progress by mass changes  determine the calibration factor of a calorimeter  determine the enthalpy change of food-related chemical reactions involving: an acid- base reaction, and a redox reaction  construct a simple calorimeter to measure the energy content of a food, for example biscuits, popcorn; compare experimental values with reported values; suggest improvements to the design of the calorimeter that will improve accuracy  analyse temperature-time graphs obtained from solution calorimetry  undertake quantitative exercises related to solution and bomb calorimetry

Detailed example ANALYSIS AND EVALUATION OF THE USEFULNESS AND VALIDITY OF THE GLYCEMIC INDEX (GI) Introduction The glycemic index (GI) was primarily developed to minimise insulin problems in people with diabetes. This index is a numerical index that ranks carbohydrates in terms of the rate of their conversion by metabolic processes to glucose within the human body. Pure © VCAA 2016 56 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS glucose is the standard and is assigned a value of 100. The values of other carbohydrates on this index are determined by experimentation using human subjects. Aim and method Students: are provided with stimulus material related to the determination of the GI, for example: http://nutritiondata.self.com/topics/glycemic-index http://ajcn.nutriton.org/content/76/1/5.full.pdf http://lpi.oregonstate.edu/mic/food-beverage/glycemic-index-glycemic-load www.glycemicindex.com answer a series of questions set over a range of thinking skills, focusing on the outline of the design and limitations of the experiments used to establish a GI index. Questions 1. Outline the experimental procedure that is used to determine the value of a food on the glycemic index. 2. One essential feature of a reliable experiment is that the same results should be obtained no matter who conducts the experiment, provided the experiment is conducted under the same conditions. Have consistent values of foods on the scale been obtained? If not, why not? State your reasoning. 3. Evaluate the design of the experiments that are conducted to assign a GI value to foods. Outline at least two limitations to the design. 4. Suggest how one of the limitations to the design that you have identified might be overcome or its effect minimised. 5. Given the purpose of establishing the GI index, what are two problems that can arise out of it being used by the general public? 6. If you were asked to educate the general public about how our body processes carbohydrates, and using the GI index and the GI values that are provided with some of the foods they consume, what are two major points that you would make? Extension ‘Glycemic load’ is often used in conjunction with ‘Glycemic Index’. Justify a response as to whether, in terms of improving people’s health, it would be more helpful to educate them about their glycemic load rather than the glycemic index? Suggest how an international GI database could be used (access Australian research into GI foods and an Australian-developed international GI database through www.glycemicindex.com).

© VCAA 2016 57 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Area of Study 3: Practical investigation Outcome 3: Examples of learning activities Design and undertake a  download and print prepared scientific posters (for practical investigation example, from related to energy and/or https://ugs.utexas.edu/our/poster/samples); work in food, and present groups and use a provided set of criteria to evaluate methodologies, findings investigation aims, methodologies, data presentation, and conclusions in a conclusions and effectiveness of scientific communication scientific poster. for each poster  organise small group discussions in class to identify the strengths, weaknesses and areas for improvement of a range of scientific posters, for example, those found at www.utexas.edu/ugs/our/poster/samples; collate and reflect on class results and provided online evaluations to develop a set of ‘do’s’ and ‘don’ts’ for constructing a scientific poster (see Appendix 6)  comment, in terms of the importance of scientific communication, on Anthony Hewish’s quote that: ‘I believe scientists have a duty to share the excitement and pleasure of their work with the general public, and I enjoy the challenge of presenting difficult ideas in an understandable way.’  debate ‘that it is more important, in presentations, to impress rather than to inform’  discuss the importance of developing investigable questions for scientific investigation in light of Albert Einstein’s quote that: ‘The important thing is not to stop questioning’, Robert Half’s quote that ‘Asking the right questions takes as much skill as giving the right answers’ and Nancy Willard’s quote that ‘Sometimes questions are more important than the answers’  comment, in terms of the nature of science, on Bill Gaede’s quote that ‘Science is not about making predictions or performing experiments. Science is about explaining.’  compare combustion and properties of biodiesel made from different oils www.seminarsonly.com/Engineering- Projects/Chemistry/Biodiesel.php  design and perform experiments to determine whether the resultant heat of combustion of a mixture of fuels is related to the proportion of fuels in the mixture and their ∆H values (for example, if Fuel A has a ∆H of 1200 kJ mol-1 and Fuel B has a ∆H of 1800 kJ mol-1 then will a 50:50 mixture of the fuel have a ∆H of 1500 kJ mol-1?) formulate a hypothesis and then design and perform an experiment to investigate how molecular shape of a fuel molecule affects its heat of combustion, for example:

Do the heats of combustion of the three isomers of C4H9OH (butan-1-ol, butan-2-ol and 2-methyl-propan-2-ol) have similar ∆H values? Does the presence of oxygen in a molecule make a molecule more combustible (for example, compare hexane and hexanol)?

© VCAA 2016 58 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS  design and construct a torsion viscometer; use it to compare the viscosities of different fuels or hydrocarbons; use it to investigate and explain the differences in the ‘viscous’ properties of hens’ eggs that have been boiled for different lengths of time; suggest modifications to the design to improve accuracy of readings  design and perform an experiment to determine the optimal conditions for producing algal oil; develop criteria to enable evaluation of its usefulness as a fuel source  investigate the effectiveness of cathodic protection in inhibiting metal corrosion  investigate experimentally how changing temperatures may affect the rate or the extent of a reaction in an electrochemical or electrolytic cell  use Faraday’s Laws to determine the percentage purity of a copper sample  design, construct, test and modify a polarimeter to study chirality in glucose molecules  investigate the electrical conductivity as a function of temperature, as a hot solution of gelatine (derived from the protein collagen) cools to form a gel; explain the results in terms of protein structure and the formation of zwitterions  design and construct an optical device for measuring the concentration of a non-soluble material in aqueous colloid systems; use your device to measure the fat content of different types of milk  compare the effectiveness of using direct titration against using a thermometric titration (where the temperature change is measured each time a portion of acid is added, with the highest temperature indicating the endpoint of the reaction) to determine the endpoint of a titration using sodium hydroxide solution and hydrochloric acid  use a back titration to calculate an unknown amount of an organic compound in a consumer product; discuss why a direct titration was an inappropriate analytical technique for the purpose  devise and test a model of the relationship between the structures of different triglycerides and their melting points  investigate the temperature range over which chocolate can exist in both molten and solid states and its dependence on relevant parameters; note: chocolate appears to be a solid material at room temperature but melts when heated to around body temperature, and then when cooled down again it often stays melted even at room temperature; explain these phenomena in terms of what may be happening from a molecular structure perspective  investigate the change in viscosity when a mixture of starch, for example cornflour or cornstarch, is mixed with water and stirred  design and perform an experiment to determine whether © VCAA 2016 59 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS the sugar content (for example glucose:fructose proportions) of a fruit is related to its degree of ripeness  design and perform an experiment to compare the fermentation rates of sucrose, glucose and fructose: individually, using different combinations, and using different percentage compositions; justify experimental design by taking into account that grape juice is made up of approximately equal proportions of glucose and fructose  investigate the ripening of bananas after they have been picked (their average starch content just before ripening reaches 25 per cent and drops over a few days of ripening to less than 1 per cent, with the drop in starch content to an increase first in sucrose followed by glucose and fructose); measure the amount of glucose during the ripening process by using either glucose test strips or a glucometer, or perform titrations using either Benedict’s solution or iodine/thiosulfate  design and perform experiments to further investigate the properties of vitamins, for example: Are water-soluble vitamins more prone to destruction by cooking than non-water-soluble vitamins? Which cooking methods preserve the most Vitamin C in carrots? Do water-soluble vitamins react differently to UV light than non-water-soluble vitamins? When is the Vitamin C content of fruit at its peak?  investigate experimentally the sensitivity of Vitamin C to light, oxygen or pH  investigate experimentally the claims that: citric acid can be considered as an antioxidant mainly due to its low pH and that other fruit acids could also act as antioxidants if their pH was low enough a 0.01% solution of EDTA (ethylene diamine tetraacetic acid) protects apple juice from oxidation a 0.9% solution of sodium chloride may act to counter the oxidation of ascorbic acid some fruit juices contain substances that help destroy Vitamin C, for example, apple juice held at 37 °C with a pH of 3.5 for 60 days will lose about 99% of its ascorbic acid, while pineapple juice under the same conditions will lose about 70%  compare the accuracy and precision of using a DCPIP titration versus an iodine titration to determine the Vitamin C content of fruit juices  determine whether colorimetry is an accurate measure of Vitamin C loss from fruit juice, based on the observation that fruit juices get darker as Vitamin C breaks down  design and conduct an experiment to compare the rates of enzyme activity in different brands of lactase pills that are used by lactose-intolerant individuals to break down the lactose in milk

© VCAA 2016 60 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS (wwww.biologycorner.com/worksheets/enzyme_lab.html)  determine the peroxidase activity per gram of fruit or vegetable, for example potatoes, carrots, tomatoes, kiwifruit, cauliflower, green beans, horseradish, turnips, zucchinis  use the Briggs-Rauscher reaction to determine which fruits or teas contain the most antioxidants, as outlined at www.educationscotland.gov.uk/resources/ng/h/nqresourc e_tcm4664848.asp  investigate the chemistry underpinning the claim that the following is a ‘chemical-free and easy way to clean fruit’: fill a sink with water, add 1 cup of vinegar and stir; add all fruit and soak for 10 minutes (water will be dirty and fruit will sparkle with no wax or dirty film); great for berries as it keeps them from moulding; do this with strawberries and they last for two weeks  investigate how the calorimetric technique for the measurement of the heat content of foods and fuels in a school laboratory can be improved

© VCAA 2016 61 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Detailed example HOW CAN THE CALORIMETRIC TECHNIQUE FOR THE MEASUREMENT OF THE HEAT CONTENT OF FOODS AND FUELS IN A SCHOOL LABORATORY BE IMPROVED? This practical investigation builds on knowledge and skills developed in Unit 3 Area of Study 1 and particularly in Unit 4 Area of Study 2. Teachers are reminded that the students must initially select their own topics within the scope of the school’s resources, frame their own research questions and design their own investigations. Background Following work on the heat of combustion of fuels (Unit 3) and on calorimetry and the heat content of foods (Unit 4), a student has expressed interest in the problem of the loss of heat energy when measuring the heat energy that is released when a fuel or food is burned in a school laboratory. The student has performed a simple experiment in class in which the molar heat of combustion of ethanol was determined by measuring the temperature rise of water contained in a can above the flame. The student has compared this with the published value, noted the large discrepancy with the experimental value and identified some key sources of error that led to this discrepancy. The student has read widely about the design of bomb calorimeters and processed second-hand-data from them and has seen in media reports that in addition to it being used as a material for wall insulation in homes, people suffering from hypothermia or from severe burns are wrapped in aluminium foil to help prevent loss of body heat. The student has expressed an interest in designing an experimental set-up and procedure that will lead to a more accurate result, and poses a question for investigation. The student has proposed an investigation question: ‘How can the calorimetric technique for the measurement of the heat content of foods and fuels in a school laboratory be improved?’ Planning the investigation The student: plans to design and trial different experimental set-ups and procedures to identify which one leads to results that are closest to the published molar heat of combustion of ethanol and the published heat content of a biscuit; in each case the student will use the specific heat capacity of water and the temperature rise of water to determine the heats of combustion of the samples makes a written and photographic record of the experimental set-up used in each trial, as well as records all measurements taken (the student’s prior learning includes understanding that each piece of equipment used will have its own specific heat capacity, and that heat energy loss to the surroundings is the major source of error), and should seek the assistance of the teacher in identifying the risk factors involved should the investigation include using a source of oxygen to make the combustion more efficient, as is used in a bomb calorimeter. The student consults with the laboratory technician about the equipment, the materials required and the health and safety protocols to be implemented when burning materials. Methodology The student identifies three major areas in which the experimental design might be improved: the container in which the water is heated, the use of insulation around the apparatus, and the flow of oxygen to the flame. The student tests each area in turn, keeping all other variables controlled, and then tests the combination of conditions that has led to the most accurate results. The student is supplied with ethanol, an unopened new packet of biscuits, a spirit burner, a crucible, a wide roll aluminium foil, a large polystyrene foam box, and other relevant equipment and materials.  The water container Six different water containers are set up using different shapes and materials. Three are made from copper and the other three from tin-plated steel. For each material, one is a tall cylindrical shape like a drink can, with an open end at the top, one has the same shape and size but has a wooden lid placed over it with two holes for the

© VCAA 2016 62 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS stirrer and thermometer, and the third is the same as the second with the addition of aluminium foil wrapped tightly around its curved surface.  Insulation around the apparatus Three different arrangements are set up. In the first, no insulating material is used. In the second, the entire apparatus is encased in an envelope of aluminium foil with an entry and an exit hole for air-flow on opposite sides. In the third, the polystyrene box is up-ended over the apparatus and two holes are drilled into it at opposite ends for air-flow.  Flow of oxygen to the flame Three different arrangements are trialled. In the first, the natural flow of air is used. In the second, a small hair drier is used on a cold setting to slightly increase the speed of air flowing to the flame. In the third, oxygen gas produced by the addition of manganese dioxide catalyst to hydrogen peroxide solution is directed to the flame via a plastic tube. Results The student photographs each set-up that is trialled, and measures and records the mass of the fuel and biscuit burned, and the temperature rise in the same mass of water for both the ethanol and the biscuit for each set of conditions tested. The molar enthalpy of ethanol and the heat content of the biscuits are calculated from these results. The results are presented in two tables, one for ethanol and one for the biscuit. The photographs are printed and appropriately labelled to show the conditions used for each trial. Discussion The student analyses the results, and considers the limitations of the investigation and how the investigation could be improved. The student considers the need to account for why the set of conditions that led to the most accurate results for the combustion of the ethanol and of the biscuit worked best. Conclusion The student uses the data collected to respond to the investigation question asked.

Sample approach to developing an assessment task

Unit 3

Area of Study 1: What are the options for energy production?

Outcome 1 Compare fuels quantitatively with reference to combustion products and energy outputs, apply knowledge of the electrochemical series to design, construct and test galvanic cells, and evaluate energy resources based on energy efficiency, renewability and environmental impact. Step 1: Define the parameters of the outcome, including relevant key knowledge and key science skills, and the related assessment task options Review the outcome for Unit 3 Area of Study 1 and identify the key knowledge from page 26 and relevant key science skills from pages 10 and 11 of the VCE Chemistry Study Design that students will be expected to develop. For some outcomes the assessment of achievement may best be structured by using more than one assessment task; teachers should exercise judgment in the determination of the number of tasks in the assessment of an outcome to balance assessment of student performance and student workload. Assessment task/s will contribute to the determination of an S or an N for the outcome. The assessment task for this outcome requires students to undertake one or more of the four tasks listed on page 29 of the VCE Chemistry Study Design. The task accounts for 50 marks of the 100 marks available for School-assessed Coursework in Unit 3 and contributes 8 per cent to a student’s study score for VCE Chemistry. Step 2: Decide on the type of task and review the conditions under which the task will be conducted A detailed description of task types for VCE Chemistry may be found in Appendix 7. Tasks should be completed under supervision for authentication purposes and should not exceed 50 minutes and/or 1000 words. Reading time should be built into the assessment task in addition to allocating time for the response. Students may need to access data and information from their logbooks in order to be able to respond to the task. Prior to the task students should be advised of the timeline and the conditions under which the task will be conducted, and have an indication of the knowledge and skills that will be assessed. Step 3: Examine the assessment advice in this handbook Review the performance descriptors as they provide an indication of qualities and characteristics that teachers should look for in a student response. Step 4: Design the assessment task Consider what it will look like when students develop the identified key knowledge and key skills then use this as a basis to develop a valid assessment task. The assessment task should allow students to demonstrate their chemical knowledge in terms of relevant concepts and skills. One assessment task for Unit 3 Outcome 1 is a reflective learning journal/blog related to selected activities or in response to an issue.

© VCAA 2016 64 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Teachers will determine the nature, number and timeframe of students’ blog responses to an aspect of energy production and use in society, including how the blogs will be assessed. Students should work individually but will be expected to respond to blog posts by other students. Blogging facilities and protocols should be set up in advance and discussed with students. Students should be informed of the nature of the assessment task, provided with the assessment criteria for the task and informed about the weighting given to various components of the task. In this example the teacher used the question ‘How green are biofuels?’ as the topic for consideration by students. There are three stages in this example. Stage 1: The teacher provides students with two short statements or paragraphs related to one advantage and one disadvantage of the production and/or use of biofuels. This is done towards the end of each lesson for three lessons. Students are given 10 minutes to post their blogs, identifying and commenting on the chemical concepts involved. Suitable statements or paragraphs involving the advantages and disadvantages of the production and/or use of biofuels may relate to: renewability; use of land and impact on food security; availability of source crop; energy, water and other resources involved in biofuel production; energy use and related wastes; and safety. Students are required to respond to at least one other student’s blog prior to the next lesson. Stage 2: The teacher assesses the blogs and provides feedback to students prior to the second stage of the assessment so that students may review the chemical concepts associated with the advantages and disadvantages of the use of biofuels. Stage 3: In the next session students have access to their own blogs and are given 20 minutes to provide a response to an overview question that requires students to synthesise information and draw conclusions. Suitable questions include: Are biofuels ‘green’? Should biofuels be subsidised to promote their use? Would biofuels be appropriate as an energy source to meet the needs of your home/school/community? Step 5: Determine teaching and learning activities For Unit 3 Area of Study 1, the teacher should plan a sequence of teaching and learning activities that will enable students to develop the key knowledge and key science skills and lead them towards achieving the desired outcomes. When developing teaching and learning activities, teachers should consider prior learning and alternative conceptions held by students. Teaching and learning activities that could support students to prepare for this assessment include: introductory blogging activities related to issues such as the definition of ‘renewability’ and estimates of longevity of fossil fuel supplies a set of experimental investigations recorded in their logbook related to energy content of different fuels, and stoichiometric calculations related to the combustion of fuels.

When to assess the students The teacher must decide the most appropriate time to set the task. This decision is the result of several considerations including: 1. The estimated time it will take to cover the key knowledge and skills for the outcome. 2. When assessment tasks are being conducted in other studies and the workload implications for students. Marking the task The marking scheme used to assess a student’s level of performance should reflect the relevant aspects of the performance descriptors and be explained to students before commencing a task. Performance descriptors provide a guide to the levels of performance typically demonstrated within each range on the assessment task/s. The performance descriptors for each outcome identify the qualities or characteristics expected in a student response. Authentication Authentication issues can be minimised if students complete the assessment task largely under supervision and if the assessment task is new for that cohort of students. Authentication issues will also be minimised by changing the selected issues on which the assessment task/s are based or the type of assessment task/s from year to year.

Unit 4

Area of Study 2: What is the chemistry of food?

Outcome 2 Distinguish between the chemical structures of key food molecules, analyse the chemical reactions involved in the metabolism of the major components of food including the role of enzymes, and calculate the energy content of food using calorimetry. Step 1: Define the parameters of the outcome, including relevant key knowledge and key science skills, and the related assessment task options Review the outcome for Unit 4 Area of Study 2 and identify the key knowledge from pages 32 and 33 and relevant key science skills from pages 10 and 11 of the VCE Chemistry Study Design that students will be expected to develop. For some outcomes the assessment of achievement may best be structured by using more than one assessment task; teachers should exercise judgment in the determination of the number of tasks in the assessment of an outcome to balance assessment of student performance and student workload. Assessment task/s will contribute to the determination of an S or an N for the outcome. For this outcome, there is a choice of four tasks as listed on page 35 of the VCE Chemistry Study Design. Teachers may produce an assessment template for students to complete the task. The selected task accounts for 30 marks of the 90 marks available for School-assessed Coursework in Unit 4 and contributes 8 per cent to a student’s study score for VCE Chemistry. Step 2: Decide on the type of task and review the conditions under which the task will be conducted A detailed description of task types for VCE Chemistry may be found in Appendix 7. Tasks should be completed under supervision for authentication purposes and should not exceed 50 minutes and/or 1000 words. Reading time should be built into the assessment task in addition to allocating time for the response. Students may need to access data and information from their logbooks in order to be able to respond to the task. Prior to the task students should be advised of the timeline, the conditions under which the task will be conducted and have an indication of the knowledge and skills that will be assessed. Step 3: Examine the assessment advice in this handbook Review the performance descriptors as they provide an indication of qualities and characteristics that teachers should look for in a student response. Step 4: Design the assessment task Consider what it will look like when students develop the identified key knowledge and key skills then use this as a basis to develop a valid assessment task. The assessment task should allow students to demonstrate their chemical knowledge in terms of relevant concepts and skills. One assessment task for Unit 4 Outcome 2 is a report of a laboratory investigation. Students may work in pairs to conduct the laboratory investigation on the effects of temperature on the action of the enzyme rennin to coagulate the casein (a protein) from milk as an initial stage in cheesemaking. Students will be allocated a specific temperature for their investigation (for example, 0 oC, 15 oC; 25 oC, 30 oC, 50 oC and 100 oC) and will have 50

© VCAA 2016 67 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS minutes to complete the practical activity. Class results will be collated and presented to students in a subsequent 40-minute session, where students produce an independent report of the class investigation. Students should use their own logbook throughout the investigation. The teacher will collect the logbook and monitor the student’s progress through observations and discussions with students. The final report should contain results presented in a suitable format, a discussion of the data and procedures and a conclusion related to the stated aims of the investigation and based on the results obtained. In this example there are three stages. Stage 1: The lesson before the laboratory investigation, students are given a copy of the aims, materials and methods of a laboratory investigation on the effects of temperature on the action of rennin to coagulate the casein from milk. Students are also given the assessment criteria for this task. Stage 2: Students conduct the laboratory investigation in pairs in the 50-minute session. Students are assessed for their laboratory skills, including safe work practices. Results are recorded and any alterations to the prescribed method noted by the teacher or students. Logbooks are collected at the end of the session by the teacher. Stage 3: In the next session students are given back their logbooks, a set of collated class data for the investigation and a list of questions that must be addressed in their discussion. Students are then given 40 minutes to complete their report. Step 5: Determine teaching and learning activities For Unit 4 Area of Study 2 the teacher should plan a sequence of teaching and learning activities that will enable students to develop the key knowledge and key science skills and lead students towards achieving the desired outcomes. Teaching and learning activities that could support students to prepare for this assessment include: modelling of primary, secondary, tertiary and quaternary structures of proteins simulations/models of lock-and-key and induced fit models of enzyme activity, and a set of experimental investigations recorded in their logbook related to food chemistry. When to assess the students The teacher must decide the most appropriate time to set the task. This decision is the result of several considerations including: 1. The estimated time it will take to cover the key knowledge and skills for the outcome. 2. When assessment tasks are being conducted in other studies and the workload implications for students. Marking the task The marking scheme used to assess a student’s level of performance should reflect the relevant aspects of the performance descriptors and be explained to students before commencing a task. Performance descriptors provide a guide to the levels of performance typically demonstrated within each range on the assessment task/s. The performance descriptors for each outcome identify the qualities or characteristics expected in a student response. Authentication Authentication issues can be minimised if students complete the assessment task under supervision and if the assessment task is new for that cohort of students. Authentication

© VCAA 2016 68 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS issues can also be minimised by changing the selected practical activities and/or contexts on which the assessment task is based or the type of assessment task from year to year.

CHEMISTRY SCHOOL-ASSESSED COURSEWORK

Performance descriptors

Unit 3 DESCRIPTOR: typical performance in each range Outcome 1 Very low Low Medium High Very high Compare fuels Very limited quantitative Limited quantitative comparison Sound quantitative comparison Well-developed quantitative Comprehensive quantitative quantitatively comparison of fuels with some of fuels with some reference to of fuels with appropriate comparison of fuels with comparison of fuels with detailed reference to combustion combustion products and reference to combustion accurate reference to reference to combustion with reference products and outputs. outputs. products and outputs. combustion products and products and outputs. to combustion outputs. products and Very limited application of the Some application of the Adequate application of the Effective application of the Highly proficient application of energy outputs, electrochemical series to the electrochemical series to the electrochemical series to the electrochemical series to the the electrochemical series to the apply design, construction and testing design, construction and testing design, construction and testing design, construction and testing design, construction and testing knowledge of of galvanic cells. of galvanic cells. of galvanic cells. of galvanic cells. of galvanic cells. the Very limited evaluation of energy Some evaluation of energy Satisfactory evaluation of energy Detailed evaluation of energy Sophisticated evaluation of electrochemical resources with reference to resources with reference to resources with reference to resources with reference to energy resources with reference series to energy efficiency, renewability energy efficiency, renewability energy efficiency, renewability energy efficiency, renewability to energy efficiency, renewability design, and environmental impact. and environmental impact. and environmental impact. and environmental impact. and environmental impact. construct and Very limited collection of relevant Very limited collection of relevant Appropriate collection of relevant Purposeful collection of relevant Highly proficient collection of test galvanic data and limited use of simple data and some use of data from data and sound use of data from data and accurate use of data relevant data and insightful use data from experiments, texts, experiments, texts, tables, experiments, texts, tables, from experiments, texts, tables, of complex data from cells, and tables, graphs and diagrams to graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer experiments, texts, tables, evaluate energy answer questions, to draw questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions graphs and diagrams to answer resources based conclusions and to recognise and to recognise experimental and to recognise experimental and to recognise experimental questions, to draw conclusions on energy experimental errors and errors and limitations. errors and limitations. errors and limitations. and to recognise experimental limitations. errors and limitations. efficiency, renewability Very limited use of chemical Some appropriate use of Appropriate use of most Effective and appropriate use of Proficient and highly appropriate and terminology, units, chemical terminology, units, chemical terminology, units, chemical terminology, units, use of chemical terminology, representations and conventions representations and conventions representations and conventions representations and conventions units, representations and environmental in explaining qualitative and in explaining qualitative and in explaining qualitative and in explaining qualitative and conventions in explaining impact. quantitative concepts. quantitative concepts. quantitative concepts. quantitative concepts. qualitative and quantitative concepts. KEY to marking scale based on the outcome contributing 50 marks

Very Low 1–10 Low 11–20 Medium 21–30 High 31–40 Very High 41–50

DESCRIPTOR: typical performance in each range Very low Low Medium High Very high Very limited application of rate Some application of rate and Appropriate application of rate Competent application of rate Highly proficient application of and equilibrium principles in equilibrium principles in and equilibrium principles in and equilibrium principles in rate and equilibrium principles predicting how rate and extent predicting how rate and extent predicting how rate and extent predicting how rate and extent in predicting how rate and of reactions can be optimised. of reactions can be optimised. of reactions can be optimised. of reactions can be optimised. extent of reactions can be Unit 3 optimised. Some description of the Some explanation of the Satisfactory explanation of the Well-developed explanation of Comprehensive explanation of Outcome 2 involvement of electrolysis in involvement of electrolysis in involvement of electrolysis in the involvement of electrolysis the involvement of electrolysis the production of chemicals the production of chemicals the production of chemicals in the production of chemicals in the production of chemicals Apply rate and and/or in the recharging of and/or in the recharging of and/or in the recharging of and/or in the recharging of and/or in the recharging of equilibrium principles batteries. batteries. batteries. batteries. batteries. to predict how the rate and extent of reactions Very limited collection and Limited collection and Appropriate collection and Purposeful collection and clear Highly proficient collection and can be optimised, and presentation of data and presentation of relevant data presentation of relevant data presentation of relevant data presentation of relevant data representation of experimental and representation of and representation of and representation of and representation of explain how findings. experimental findings. experimental findings. experimental findings. experimental findings. electrolysis is involved in the production of Very limited use of qualitative Some use of qualitative and Appropriate use of qualitative Accurate use of qualitative and Insightful use of qualitative and chemicals and in the and quantitative data from quantitative data from and quantitative data from quantitative data from quantitative data from recharging of experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer batteries. questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions and to recognise experimental and to recognise experimental and to recognise experimental and to recognise experimental and to recognise experimental errors and limitations. errors and limitations. errors and limitations. errors and limitations. errors and limitations. Very limited use of chemical Some appropriate use of Appropriate use of most Effective and appropriate use of Proficient and highly terminology, units, chemical terminology, units, chemical terminology, units, chemical terminology, units, appropriate use of chemical representations and representations and representations and representations and terminology, units, conventions in explaining conventions in explaining conventions in explaining conventions in explaining representations and qualitative and quantitative qualitative and quantitative qualitative and quantitative qualitative and quantitative conventions in explaining concepts. concepts. concepts. concepts. qualitative and quantitative concepts.

KEY to marking scale based on the outcome contributing 50 marks

CHEMISTRY

DESCRIPTOR: typical performance in each range Very low Low Medium High Very high Very limited comparison of Some comparison of general Satisfactory comparison of Well-considered comparison of Comprehensive comparison of general structures and reactions structures and reactions of major general structures and reactions general structures and reactions general structures and reactions of major organic families of organic families of compounds. of major organic families of of major organic families of of major organic families of Unit 4 compounds. compounds. compounds. compounds. Very limited understanding of Basic understanding of the Adequate understanding of the Well-developed understanding Thorough understanding of the Outcome 1 the principles of analytical principles of analytical chemistry principles of analytical chemistry of the principles of analytical principles of analytical chemistry chemistry techniques and some techniques and some techniques and mostly correct chemistry techniques and techniques and justified correct Compare the identification of simple organic identification of organic identification of organic correct identification of organic identification of organic general structures compounds using instrumental compounds using instrumental compounds using instrumental compounds using instrumental compounds using instrumental and reactions of analysis data analysis data analysis data analysis data analysis data the major organic Incomplete or inaccurate design Some complete or accurate Mostly complete and accurate Complete and accurate design Highly proficient design of families of of reaction pathways for organic designs for reaction pathways design of reaction pathways for of reaction pathways for organic reaction pathways for organic compounds, molecule synthesis. for organic molecule synthesis. organic molecule synthesis. molecule synthesis. molecule synthesis, including deduce structures recognition of alternative of organic pathways. compounds using Very limited application of Some application of volumetric Satisfactory application of Competent application of Highly proficient application of instrumental volumetric and chromatographic and chromatographic techniques volumetric and chromatographic volumetric and chromatographic volumetric and chromatographic analysis data, and techniques in chemical analysis. in chemical analysis. techniques in chemical analysis. techniques in chemical analysis. techniques in chemical analysis. design reaction pathways for the Very limited use of data from Some use of data from Appropriate use of data from Accurate use of data from Insightful use of data from synthesis of experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, experiments, texts, tables, graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer graphs and diagrams to answer organic molecules. questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions questions, to draw conclusions and to recognise experimental and to recognise experimental and to recognise experimental and to recognise experimental and to recognise experimental errors and limitations. errors and limitations. errors and limitations. errors and limitations. errors and limitations. Very limited use of chemical Some appropriate use of Appropriate use of most Effective and appropriate use of Proficient and highly appropriate terminology, units, chemical terminology, units, chemical terminology, units, chemical terminology, units, use of chemical terminology, representations and conventions representations and conventions representations and conventions representations and conventions units, representations and in explaining qualitative and in explaining qualitative and in explaining qualitative and in explaining qualitative and conventions in explaining quantitative concepts. quantitative concepts. quantitative concepts. quantitative concepts. qualitative and quantitative concepts. KEY to marking scale based on the outcome contributing 30 marks

Very Low 1–6 Low 7–12 Medium 13–18 High 19–24 Very High 25–30 CHEMISTRY SCHOOL-ASSESSED COURSEWORK

© VCAA 2016 72 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS DESCRIPTOR: typical performance in each range Very low Low Medium High Very high Unit 4 Very limited recognition of the chemical Some distinction Satisfactory distinction between the Mostly accurate and complete Accurate and complete structures of key food molecules. between the chemical chemical structures of key food distinction between the chemical distinction between the chemical Outcome 2 structures of key food molecules. structures of key food molecules. structures of key food molecules. molecules. Distinguish Incomplete understanding of the chemical Basic understanding of Satisfactory understanding of the Well-developed understanding of the Comprehensive understanding between the reactions involved in the metabolism of food. the chemical reactions chemical reactions involved in the chemical reactions involved in the of the chemical reactions chemical involved in the metabolism of food, including some metabolism of food, including involved in the metabolism of structures of metabolism of food. recognition of reaction conditions identification of reaction conditions food, including explanation of key food and mechanisms. and mechanisms. reaction conditions and mechanisms. molecules, analyse the Very limited accuracy of calculations of the Some errors in Mostly correct calculations of the Error-free calculations of the energy Error-free calculations including energy content of food using provided data calculating the energy energy content of food using content of food using provided data correct number of significant chemical and/or data from primary investigations. content of food using provided data and/or data from and/or data from primary figures of the energy content of reactions provided data and/or primary investigations. investigations. food using provided data and/or involved in data from primary data from primary investigations. the investigations. metabolism Very limited application of calorimetry in Some application of Satisfactory application of Competent application of calorimetry Highly proficient application of of major determining the energy content of food. calorimetry in calorimetry in determining the in determining the energy content of calorimetry in determining the components determining the energy energy content of food, including food, including description of some energy content of food, including content of food. identification of some limitations of limitations of calorimetric explanation of limitations of of food calorimetric methodologies. methodologies. calorimetric methodologies. including the Very limited use of data from experiments, Some use of data from Appropriate use of data from Accurate use of data from Insightful use of data from role of texts, tables, graphs and diagrams to answer experiments, texts, experiments, texts, tables, graphs experiments, texts, tables, graphs experiments, texts, tables, enzymes, and questions, to draw conclusions and to tables, graphs and and diagrams to answer questions, and diagrams to answer questions, to graphs and diagrams to answer calculate the recognise experimental errors and limitations. diagrams to answer to draw conclusions and to draw conclusions and to recognise questions, to draw conclusions energy questions, to draw recognise experimental errors and experimental errors and limitations. and to recognise experimental conclusions and to limitations. errors and limitations. content of recognise experimental food using errors and limitations. calorimetry. Very limited use of chemical terminology, Some appropriate use of Appropriate use of most chemical Effective and appropriate use of Proficient and highly appropriate units, representations and conventions in chemical terminology, terminology, units, representations chemical terminology, units, use of chemical terminology, explaining qualitative and quantitative units, representations and conventions in explaining representations and conventions in units, representations and concepts. and conventions in qualitative and quantitative explaining qualitative and quantitative conventions in explaining explaining qualitative and concepts. concepts. qualitative and quantitative quantitative concepts. concepts. KEY to marking scale based on the outcome contributing 30 marks

Very Low 1–6 Low 7–12 Medium 13–18 High 19–24 Very High 25–30 CHEMISTRY SCHOOL-ASSESSED COURSEWORK

© VCAA 2016 73 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS DESCRIPTOR: typical performance in each range Very low Low Medium High Very high Some attempt at formulation of Mostly appropriate formulation Appropriate formulation of an Accurate formulation of an Highly proficient formulation of an investigable question with very of an investigable question with investigable question with sound investigable question with well an investigable question with limited outline of investigation limited outline of investigation investigation design. constructed investigation design. sophisticated investigation design. design. design. Very limited understanding of the Limited understanding of the Sound understanding of the Thorough understanding of the Insightful understanding of the investigation with very limited investigation with some investigation with satisfactory investigation with detailed investigation with sophisticated explanation of its context, explanation of its context, explanation of its context, explanation of its context, explanation of its context, purpose, methodology and purpose, methodology and purpose, methodology and purpose, methodology and purpose, methodology and Unit 4 significance. significance. significance. significance. significance. Some attempt at collection and Some appropriate collection, Sufficient collection, selection Purposeful collection, selection Highly proficient collection, Outcome 3 use of qualitative and quantitative selection and use of qualitative and use of qualitative and and use of qualitative and selection and use of qualitative data to draw some conclusions. and quantitative data to draw quantitative data to draw justified quantitative data to draw valid and quantitative data to draw Design and undertake a relevant conclusions. conclusions. conclusions. valid conclusions. practical investigation Limited presentation of Some presentation of Appropriate presentation of Accurate presentation of Highly proficient presentation of related to energy and/or investigation results to illustrate investigation results in an investigation results in an investigation results in an investigation results in an food, and present trends, patterns and relationships appropriate format to illustrate appropriate format to illustrate appropriate format to illustrate appropriate format to illustrate methodologies, findings with limited identification of relevant trends, patterns and relevant trends, patterns and relevant trends, patterns and relevant trends, patterns and and conclusions in a investigation limitations. relationships with some relationships with sound relationships with detailed relationships with insightful identification of investigation identification of investigation identification of investigation identification of investigation scientific poster. limitations. limitations and sources of error. limitations and sources of error. limitations and sources of error. Limited description of the links Some appropriate analysis of Appropriate analysis and Detailed analysis and evaluation Sophisticated analysis and between investigation findings the links between investigation evaluation of the links between of the links between investigation evaluation of the links between and relevant scientific concepts, findings and relevant scientific investigation findings and findings and relevant scientific investigation findings and relationships and principles concepts, relationships and relevant scientific concepts, concepts, relationships and relevant scientific concepts, related to energy and/or food. principles related to energy relationships and principles principles related to energy relationships and principles and/or food. related to energy and/or food. and/or food. related to energy and/or food. Limited coherence and cohesion Some coherence and cohesion Satisfactory coherence and Mostly coherent and cohesive Coherent and cohesive in the communication of in the communication of cohesion in the communication sequencing and communication sequencing and communication investigation aims, investigation aims, of investigation aims, of investigation aims, of investigation aims, methodologies, findings and methodologies, findings and methodologies, findings and methodologies, findings and methodologies, findings and conclusions in scientific poster conclusions in scientific poster conclusions in scientific poster conclusions in scientific poster conclusions in scientific poster with limited referencing and with some referencing and with appropriate referencing and with complete referencing and with complete referencing and acknowledgments. acknowledgments. acknowledgments. acknowledgments. acknowledgments. KEY to marking scale based on the outcome contributing 30 marks

Appendix 1: Types of scientific inquiry

Scientific inquiry may be conducted by individuals or groups and may be a confirmation, structured, guided, coupled or open. These five different types of scientific inquiry can be elaborated as follows: A confirmation inquiry involves students confirming a principle through an activity when the results are known in advance; students are provided with the question, method and results, and are required to confirm that the results are correct. A structured inquiry involves students investigating a teacher-presented question through a prescribed procedure; students generate an explanation supported by the evidence they have collected. A guided inquiry involves the teacher choosing the question for investigation; students work in one large group or several small groups to work with the teacher to decide how to proceed with the investigation. This type of inquiry facilitates the teaching of specific skills needed for future open-inquiry investigations. The solution to the guided inquiry should not be predictable. A coupled inquiry combines a guided-inquiry investigation with an open-inquiry investigation: the teacher chooses an initial question to investigate as a guided inquiry and students then build on the guided inquiry to develop an extension or linked investigation in a more student-centred open inquiry approach. An open inquiry most closely mirrors scientists’ actual work and is a student-centred approach that begins with a student’s question, followed by the student (or groups of students) designing and conducting an investigation or experiment and communicating results.

Appendix 2: Scientific inquiry methods

Students studying Units 1 to 4 Chemistry may undertake a range of investigations involving different scientific inquiry methods. VCE Chemistry students undertaking scientific inquiry would be expected to: engage with science-based questions; prioritise evidence in responding to questions; formulate explanations from evidence; connect explanations to scientific knowledge; and communicate and justify explanations The following table provides an overview of different scientific inquiry methods that may be undertaken at this level.

Inquiry Inquiry outline method Controlled Experimental investigation of the relationship between an independent experiment variable and a dependent variable, controlling all other variables Examples of types of questions or investigations:  What effect does…have on…?  Is…related to…? Pattern Investigation of one variable to determine what other variables can seeking affect it, and to what extent other variables may be important in their effects on the variable under investigation.  Observation of natural events and phenomena to identify patterns or relationships and propose causal links: examination of data sets related to a dependent variable to determine cause (independent variable); greater focus on the characteristics of the sample used since variables may be difficult or impossible to isolate and control; this is a more holistic approach that often involves observation and recording of multiple variables Examples of types of questions or investigations:  What factors affect…?  What are the optimal conditions for…?  Surveys (especially in genetics, epidemiology, psychology, sociology, astronomy and ecology): comparison of data sets to identify patterns or relationships and propose causal links Examples of types of questions or investigations:  Conduct a survey to… Single Investigation of one variable or factor at a time, usually to see how it variable changes over time, focusing on observations and identification of a exploration phenomenon; often this type of exploration leads to questions about the causes of an observed phenomenon and leads to further types of inquiry Examples of types of questions or investigations:  How does…change over time?  Do all…?  When does…?

© VCAA 2016 76 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Classification Classification is the arrangement of phenomena (objects or events) into and manageable sets while identification is a process of recognition of identification phenomena as belonging to particular sets or possibly being part of a new or unique set; these inquiries involve the identification of features, tests or procedures that discriminate between objects or processes Examples of types of questions or investigations:  Develop a key to…?  Adapt…to categorise…? Product, Design of an artefact, process or system to meet a human need; may process or involve technological applications in addition to scientific knowledge and system procedures to answer questions or solve problems development Examples of types of questions or investigations:  Design, construct, test and evaluate…  Design a regime to…  Is there a better way to…? Investigation Student-developed model as an explanation of an everyday of scientific phenomenon or a laboratory-observed phenomenon; this type of inquiry models incorporates a stage where students need to decide what evidence should be collected in order to physically test the ideas embedded in conceptual models Examples of types of questions or investigations:  Devise an inquiry to test an explanation of…  Devise and test a model of the relationship between…and…  Can the …model be adapted to explain…?

Appendix 3: Controlled experiments and hypothesis formulation

Once a topic has been identified students develop a research question for investigation, which may involve formulating a hypothesis. Teachers should guide students so that they do not proceed with a research question or hypothesis that is not testable.

Variables The formulation of a hypothesis includes the identification and control of variables. A variable is any quantity or characteristic that can exist in differing amounts or types and can be measured. Values for variables may be categorical or they may be numerical, having a magnitude. Not all variables can be easily measured. Length can be measured easily using, for example, metre rulers. Shades of colour are less easily measured and are more likely to be subjective. They might be measured by, for example, using photographic comparisons to produce a set of graduated ‘standards’ that are nominated and named for the purposes of the investigation. In VCE Chemistry, students are required to identify independent and dependent variables. They should also understand the need to control other variables (extraneous variables including confounding variables) that may affect the integrity of the experiment and the interpretation of results. Operationalisation of variables is beyond the scope of the VCE Chemistry Study Design. Concepts related to variables that apply to VCE Chemistry are specified in Appendix 4.

Developing a testable hypothesis A hypothesis is developed from a research question of interest and provides a possible explanation of a problem that can be tested experimentally. A useful hypothesis is a testable statement that may include a prediction. In some cases, for example in exploratory or qualitative research, a research question may not lend itself to having an accompanying hypothesis; in such cases students should work directly with their research questions. There is no mandated VCE Chemistry style for writing a hypothesis. Recognition of null and alternate hypotheses, one- and two-tailed hypotheses, and directional and non-directional hypotheses is not required. The following table provides an example of how a hypothesis may be constructed from a research question using an ‘If-then-when’ construction process: Stage 1. Ask a research question related to a chemical reaction under investigation: How much magnesium oxide can be produced from a given quantity of magnesium? Stage 2. Identify the independent variable (IV): initial mass of magnesium undergoing combustion. Stage 3. Identify the dependent variable (DV): final mass of magnesium oxide produced in the reaction. Stage 4. Construct a hypothesis: Follow steps 1 to 6 below:

Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 If… relationship phrase …then… trend indicator …when… trend indicator (the (to the IV) (effect on the DV) (action by the IV). DV)…

…depends on… ...show an …increased/ increase/ decreased… decrease ... …results from… …greater/ less… …be greater …is affected by… than/less than… …large/small…

…is directly …be larger related to… /smaller… Hypothesis: If magnesium reacts with oxygen in a 1:1 ratio, then 12.9 g of magnesium oxide will form when 7.80 g of magnesium undergoes complete combustion in oxygen. Teachers should note that alternative writing styles for hypotheses can be equally valid. Some hypotheses include reasons for the inherent prediction, for example, the above hypothesis may be extended as: ‘If magnesium reacts with oxygen in a 1:1 ratio because both elements form divalent ions, then 12.9 g of magnesium oxide will form when 7.80 g of magnesium undergoes complete combustion in oxygen.’

Appendix 4: Defining variables

The table identifies types of variables that apply to VCE Chemistry.

Type of Definitions variable Categorical Categorical variables are qualitative variables that describe a quality or characteristic typically addressing ‘what type?’ or ‘which category?’. They are generally represented by non- numeric values and may be further classified as ordinal or nominal. Ordinal variables can take values that can be logically ordered or ranked, for example, ionisation energies (1st, 2nd 3rd), degree of satisfaction with a new gadget (small, medium, large) and attitudes (strongly agree, agree, disagree, strongly disagree) Nominal variables can take values that cannot be organised in a logical sequence, for example, gender, colour and type of sub-atomic particle Bar charts and pie graphs are used to graph categorical data. Numerical Numerical variables are quantitative variables that describe a measurable quantity as a number, typically addressing ‘how many?’ or ‘how much?’. They are further classified as continuous or discrete. Continuous variables can take any value between a certain set of real numbers, for example, distance (2.85 kilometres), length of time (12.5 seconds) or temperature (25.4 °C) Discrete variables can take a value based on a count from a set of distinct whole values and cannot take the value of a fraction between one value and the next closest value, for example, number of carbon atoms in a polysaccharide or number of electrons in an atom Scatter plots and line graphs are used to graph numerical data. Independent An independent variable is the variable for which quantities are manipulated (selected or changed) by the experimenter, and assumed to have a direct effect on the dependent variable. Independent variables are plotted on the horizontal axis of graphs. Dependent A dependent variable is the variable the experimenter measures, after selecting the independent variable that is assumed to affect the dependent variable. Dependent variables are plotted on the vertical axis of graphs. Controlled A controlled variable is a variable that has been held constant in an experiment to test the relationship between the independent and dependent variables.

Appendix 5: Scientific poster sections

Scientific poster sections, specifically the title, introduction, methodology, results, discussion, conclusions, references and acknowledgments, are mandated. Within the mandated sections, some tailoring of organisational elements is optional. The following advice may be provided to students: Title: The poster title should be written as a question that briefly conveys the interesting issue, the general experimental approach, and the system (for example, a chemical, a model or an experimental set-up). Abstract: Inclusion of an abstract on a poster is optional. Introduction: A one- or two-sentence overview of the purpose of the investigation and why the research question is of interest should be provided. The investigation should be placed in the context of appropriate background theory (including relevant secondary sources of reliable information) and prior investigations and linked to a hypothesis (before a brief description of the experimental approach that tested a hypothesis or research question is provided). Sufficient background information, definitions and relevant formulas should be used to enable a peer to understand the nature of the investigation. Unlike a manuscript, the poster’s introduction is an appropriate place to put a photograph or illustration that communicates some aspect of the research question. Methodology: The investigation type, apparatus, materials and procedure should be described briefly although well enough to allow others to replicate it exactly. The detail used for a formal practical report is not required; for example, figures and flow charts can be used to illustrate experimental design, a photograph or labelled drawing of a system or setup may be included, and the method that was used could be summarised as a flow chart. This section should clarify why the student performed the investigation in the way that was chosen. Results: In this section, the student should select relevant raw (i.e. uninterpreted) data generated from the investigation and recorded in the student’s logbook. The student should consider the most appropriate form in which to present the data, for example table form, as an easy-to-read figure or as percentages/ratios. It is not an effective use of poster space to present both a table of results and a graph since they both represent the same information. The following points should be checked in constructing the poster: ensure that graphics are clear, easily read, titled and fully labelled clearly present data trends and/or relationships sequentially number all tables, graphs and diagrams use a sentence or two to draw attention to key points in the tables, graph and diagrams only provide a sample calculation for repeat calculations. Although this section is usually dominated by calculations, tables and figures, all significant results should be stated explicitly in prose form, including a statement about whether the investigation generated useful results and whether the hypothesis was supported.  Discussion: This section examines whether the data obtained supports the hypothesis, explores the implications of the findings and judges the potential limitations of the experimental design. It focuses on a question of understanding ‘What is the meaning and/or the significance of my investigation results?’ This involves analysis in explaining what the results clearly indicate, what has been found and what is known with certainty © VCAA 2016 81 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS based on results in order to draw conclusions as well as interpretation in explaining the significance of results, identifying ambiguities and further questions that arise, and finding logical explanations for problems in the data. In this section, the student should: Show clearly whether the data supports, partly supports or refutes the hypothesis by stating the relationships or correlations the data indicate between independent and dependent variables. The relationship between the evidence and the conclusions drawn from the evidence should be made explicit. The terms ‘proved’, ‘disproved’, ‘correct’ or ‘incorrect’ in relation to the hypothesis should be avoided since this level of certainty may be unlikely in a single investigation; terms such as ‘supported’, ‘indicated’ and ‘suggested’ are more appropriate to evaluate the hypothesis. Compare expected results with those obtained, analyse experimental design and errors and acknowledge any anomalous data or deviations from what was predicted. Ignoring data that contradicts claims or predictions is a departure from scientific method. Such data should be examined carefully and, where possible, the procedure should be repeated to obtain further data. If replication is not possible then flaws in the procedure or investigation design should be identified and the student should discuss how and why the procedure or investigation design may have affected the data, and how the procedure or investigation design could be changed to eliminate – or minimise the effects of – the identified flaws. If an experiment was within the tolerances, the student could still account for the difference from the ideal. Derive conclusions based on findings about the research question and link conclusions to the aim of the investigation. Relate findings to earlier work undertaken in the area under investigation. The investigation will be an extension of previous theoretical understandings and investigations undertaken and these should be discussed in relation to the student’s own data. If the investigation relates to a specific theory consideration of how well the theory has been illustrated may be included. Writing this section generally involves moving from the specific (directly related to the experiment) to the general (how the findings relate to wider understanding of scientific concepts). Conclusions: The conclusion should state the main investigation result and whether the hypothesis was supported. This should be justified using specific details selected from the investigation findings. The significance of the results should be discussed in terms of how they link to relevant chemical concepts and current scientific understanding, who may find the results of interest and what relevance they have in everyday applications. The conclusion is also where the limitations of the investigation design and suggested improvements could be summarised, possible future work that could be done to refine or extend conclusions could be identified and/or the implications of conclusions could be explained. References and acknowledgments: Listed references should be referred to in the body of the poster. Any standard referencing format may be followed, for example, Harvard or APA. Individuals should be thanked for specific contributions (for example, access to specialist equipment use, statistical advice, laboratory assistance) and the organisation for which they work and their position should be included. References and acknowledgments are not included in the poster word count.

Appendix 6: Suggestions for effective scientific poster communication

Scientific posters are widely used in academia, research and in the general scientific community as a visual means of communicating the outcomes of scientific investigations. Key design principles for effective scientific poster communication include: Logical sequencing and easy identification on the poster of the hypothesis or question, aim and conclusion and other key parts of the investigation. Inclusion of only the essential details for conveying what was done in the investigation and what was discovered (for example, only the key aspects of an experimental procedure should be outlined). Use of a range of visual aids (for example, tables, photographs, diagrams and graphs) to reduce the amount of text required and to avoid overcrowding of the poster. Use of font, font size and colours that will be easily read by all those viewing the poster. Careful editing of text – terminology and spelling should be checked; wording should be simplified; acronyms should be defined; and complexity should be reduced (for example, phrases or bullet points, rather than sentences, should be used). A test is that others with little or no background in the area under investigation should be able to understand the language and identify the key points of the investigation. Clear labelling of all images (for example, diagrams or photographs of the experimental set- up or results). Graphs drawn with clear, relevant scales, grids, labels and annotations. Editing of graphs derived directly from spreadsheet programs so that graphs do not have coloured backgrounds, grid lines, or boxes and that, in cases where multiple graphs are shown on the same set of axes, each graph is labelled rather than requiring a reader to use a key. Axis labels formatted in sentence case (Not in Title Case and NOT IN ALL CAPS). Calculations presented in a clear, non-repetitive manner (for example, one sample calculation can be shown and then the results of similar calculations can be displayed in a table) and appropriate units must be shown. All references stated and appropriate acknowledgments provided. Creation, printing and checking of a mock-up poster prior to submission of a final poster for assessment.

Appendix 7: Suggested approaches to assessment tasks

Students’ achievement of each outcome for each area of study must be demonstrated through performance on a selection of assessment tasks. School-based assessment tasks should be selected to reflect the key knowledge and key skills being assessed and to provide opportunities for students to demonstrate performance in ways that may not be assessable through external examinations. Assessment may be formative and/or summative and should be limited to 50 minutes per task or not exceeding 1000 words.

Assessment Scope of task task Analysis and Students may be presented with unfamiliar stimulus material related evaluation of to energy sources such as fuels and galvanic cells, and required to stimulus material analyse them in terms of the chemical reactions and energy transformations involved, and to evaluate them in terms of their suitability for a particular application, energy efficiency, renewability and/or environmental impact. They may also be required to make justified predictions about given scenarios included in the stimulus material, using appropriate chemical terminology and conventions. Analysis of an Students may be presented with unfamiliar stimulus material related unfamiliar to either a manufacturing process that involves equilibrium principles chemical or an electrolytic process. Students may be required to write relevant manufacturing chemical equations, calculate product quantities and explain the process or chemical concepts associated with the selected equilibrium or electrolytic cell electrolytic process. Annotations of Students should undertake activities and investigations relevant to activities from a the outcome prior to beginning the assessment task. The assessment practical logbook task, to be completed in class, involves annotating a selection of these activities and investigations to illustrate particular chemical principles, skills or other aspects of chemistry. Teachers should determine: which activities and investigations are undertaken for the outcome; how many of these activities and investigations should be annotated for the assessment task; whether the activities and investigations which are to be annotated for the assessment task are student-selected or teacher-selected; whether to provide a set of guiding questions to assist student annotations or whether to allow students to make their own annotations based on a general question related to a specific aspect of the relevant area of study; and when the annotations are to be completed, for example, immediately after each practical activity or investigation, after a series of activities and investigations, or in a block at the end of the area of study. Although the activities and investigations may have been completed either individually, in small groups or as a class, students must annotate the selected/relevant activities and investigations for the assessment task individually. The parameters of the assessment task should enable students to demonstrate the highest level of performance. Comparison of Students may be provided with familiar and unfamiliar structures of food molecules different food molecules and required to identify key functional groups, classify them as carbohydrates, proteins and/or fats and oils, discuss their likely properties based on their chemical structures,

© VCAA 2016 84 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS write chemical reactions for their breakdown or synthesis, explain how any unfamiliar structures may be similar to or different from familiar structures, and/or make predictions about comparative physical or chemical properties based on their chemical structures.

© VCAA 2016 85 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Comparison of two Students may be provided with two unfamiliar electricity-generating electricity- cells, or one familiar and one unfamiliar electricity-generating cell, generating cells and required to make comparisons related to the nature of the redox reactions and the cell components, design features of the cells, half- cell and overall equations, direction of electron flow in the cells, possible limitations of the cells over a period of time and/or the use of the electrochemical series to predict half-equations and overall cell equations. Data analysis Primary and/or secondary data may be used in data analysis tasks. including Teachers may use student-generated data from experiments or generalisations collated primary data from a class, across different classes within a and conclusions school, or across different schools to devise assessment tasks. Secondary data may be accessed through a variety of print and electronic resources. The task may involve students analysing a set of raw data or analysing data presented within a chemical context. Students may also analyse the generalisations and conclusions already drawn in the data, or may be required to draw their own generalisations and conclusions. Evaluation of Students may be presented with classic or contemporary research research for evaluation, or may be provided with research undertaken by VCE chemistry students in prior years. A single research study may be analysed in depth, or one or more research studies could be used to consider and/or compare chemical principles and research methodologies. Research reports do not necessarily need to be original journal articles; reports or references to chemical research accessed through a variety of print and electronic resources may be used, as long as they contain sufficient and relevant information for students to be able to evaluate chemical concepts, procedures, data and findings. If research undertaken previously by VCE students is used, then permission should be obtained from the students and the reports should be de-identified. Graphic organiser A graphic organiser is a communication tool that visually shows illustrating a knowledge, concepts, thoughts and/or ideas, and the relationships chemical process between them. Graphic organisers can take many forms, for example, relational organisers (these include fishbone diagrams, storyboards and cause-and-effect webs), classification organisers (these include concept maps and SWOT analyses), sequence organisers (these include linear diagrams, cycles and flow charts) and compare-and-contrast organisers (these include Venn diagrams and matrices). In addition to being an assessment tool, visual organisers can be used by students for summary and revision purposes. Media analysis/ Teachers should access and select a contemporary (i.e. published in response print and/or electronic media within the last calendar year) chemistry-based media item such as a press release, newspaper or journal article advertisement, interview excerpt, audiovisual program, artwork or performance item that reflects current research and/or thinking in chemistry. Students may then be asked to respond to selected chemical principles or concepts that are demonstrated through the media item. If the media item is issues-based, then students may also be asked to provide a personal perspective as a demonstration of their scientific literacy. Altering the selected article from year to year assists with assessment authentication for teachers. Reflective learning Students may post their thoughts about their own experiences, journal or blog progress and thinking in relation to teacher-selected aspects of © VCAA 2016 86 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS related to practical activities related to organic structures and/or pathways, in comparison of addition to providing comments on at least one peer’s posting at a organic structures frequency (for example twice a week) and over a time period (for or pathways example four weeks), as determined by the teacher. The subject of the blog may relate to practical skills and/or chemical concepts. The blogs should show evidence of critical, analytical reflection. Report of a The report should be preceded by a laboratory investigation that has laboratory been fully and/or partially completed under supervision and that has investigation been recorded in a student’s logbook. The logbook can then be taken into class for reference by students in producing a report in a format designated by the teacher. Reports may range from simple tabulations of results with a student comment, to full reports which include an abstract, an aim, a hypothesis, a method, results, discussion, a conclusion and references. Although laboratory investigations may be conducted individually, in small groups or as a class, reports must be completed individually. Response to a set The teacher should develop a set of multi-part questions that target of structured both key knowledge and key skills related to a chemical theme. The questions questions should be scaffolded to enable demonstration of performance at the highest levels, while providing access at each part for students to be able to provide a response independent of prior responses. This task lends itself particularly well to selecting material related to a contemporary issue in chemistry and/or to providing sets of questions that link theory and practice. Response to Students may be presented with unfamiliar stimulus material related stimulus material to food. This task lends itself particularly to selecting material related to a contemporary issue in food chemistry. Responses may take a variety of formats but students should be required to identify and discuss key chemical concepts and to provide a personal perspective related any issues associated with the stimulus material as a measure of their scientific literacy. Scientific poster An appropriately configured template must be used to report student investigation findings for Unit 4 Area of Study 3. Students and teachers may add other headings and sub-headings as pertinent to the investigation question and to the assessment rubric issued to students by the teacher prior to the task. Assessment may be completed in investigation stages, for example, investigation design, undertaking of the investigation and writing of sections of the poster. The poster may be saved as an electronic file and/or printed as a hard copy poster.

Appendix 8: Examples of problem-based learning approaches in chemistry

A problem-based learning environment is conducive to linking scientific concepts to science- based issues in society. Scenarios can be developed from actual research studies reported in scientific journals, local scenarios or issues, an imaginary scenario, an interesting chemical phenomenon or a fact-based or fictional case study as in the following example:

Step 1: Define the question/scenario/problem carefully: what are you trying to find out? Case study: The non-sparkling diamond: Problem brief: An insurance company has received a claim for $15,000 to replace a 2- carat diamond ring that a female passenger in a car claimed had been internally shattered when the car was involved in a collision with another car. The passenger claims that the diamond no longer shines as brilliantly as it did before the accident and wants to purchase a replacement diamond. In her claim, the passenger states that she has had a quote for $25,000 as a replacement ring and can sell her ‘shattered’ ring for $10,000. The passenger’s jeweller has submitted photographs that show the diamond has an ‘inclusion’. The insurance company has approached your chemistry class to investigate whether it is possible that a diamond can be shattered in a car accident, and to recommend whether the claim is legitimate and should be paid out. Student task: Draw on chemistry concepts related to covalent bonding to develop a model or simulation that demonstrates to a non-chemistry expert what would be required for a diamond to ‘internally shatter’, and to prepare a report that includes a recommendation about the legitimacy of the insurance claim. Step 2: Refine the Step 3: Plan the actual Step 4: Test ideas, obtain question/ explore possible investigation/narrow your further information, build and options/ determine what choices evaluate models other information is (class consensus) (group and/or individual) required (class brainstorming) Step 5: Write a report and present a model that draws upon relevant discussions/research/experiments, including specific scientific terminology, in response to the brief. Note: problem-based scenarios do not necessarily have a single solution

A problem-based learning approach can also be used to develop specific science skills. The skills should link to relevant chemistry content. The following example focuses on the skill of hypothesis formulation.

Step 1: Define the question/scenario/problem carefully: what are you trying to find out? Question: What factors affect crystallisation? Task: This research question requires refining with a narrower focus to develop a testable hypothesis. Step 2: Refine the Step 3: Plan the actual Step 4: Test ideas and question/explore possible investigation/ narrow your obtain further options choices information (class brainstorming) (class consensus) (group and/or individual) Possible responses: Possible responses: © VCAA 2016 88 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Possible responses: Need to identify dependent Hypothesis example: ‘If, Crystals generally grow by the and independent variables in nature, rocks that ordered deposition of solute and control other variables. have cooled quickly particles onto the surface of a Independent variable (being only contain small pre-existing crystal. selected) relates to a selected mineral crystals, then Background research may be factor relating to the set-up the slower the rate of undertaken to explore possible for the crystallisation process cooling of a solution, factors that affect to occur and could be: the larger will be the crystal that is crystallisation before a number of nucleation sites hypothesis can be formulated. produced.’ General issues for temperature Not all hypotheses are consideration include: light intensity testable and not all a. Solvent size of nucleation site variables can be controlled for some type of nucleation site polarity of the solvent. experiments. saturation level of solvent b. Solute and solution For this problem, composition of solute (for nature of solvent. students generate example, simple ionic solid; Dependent variable (being possible hypotheses; ‘double’ salt, molecular measured) relates to ‘nature provide feedback on solid – polar or non-polar) of the crystal’ that is formed each other’s solubility of solute in solvent and could be: hypotheses; modify own hypotheses. degree of saturation of solution size of crystal (for example, saturated crystal shape – degree of versus supersaturated). symmetry. c. Nucleation Control of variables is number of nucleation sites dependent on selected type of nucleation site (for independent and dependent example, small seed crystal variables. suspended into the solvent; seed crystals on base of container; scratched glass surface of container). d. Physical conditions over the time allowed for crustal growth initial temperature of solvent rate of cooling of solution intensity of light total volume and surface area of solvent degree of stillness (for example, whether vibrations, draughts or other disturbances occur) humidity of the surrounding air (in the case of water as the solvent). e. total time available for crystal growth number of days. Step 5: Write a conclusion that draws upon discussions/research/experiments, including discussion of scientific terms, control of variables and evaluation of experimental © VCAA 2016 89 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS methodology. Note: This class problem-based learning approach can be used to generate different questions for students to investigate, particularly for experimental investigations.

© VCAA 2016 90 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Appendix 9: Sample teaching plan Sample Course Outline – VCE Chemistry Unit 1: How can the diversity of materials be explained? Note: This is a sample guide only and indicates one way to present the content from the VCE Chemistry Study Design over the weeks in each school term. Teachers are advised to consider their own contexts in developing learning activities: Which local fieldwork sites would support learning in the topic area? Which local issues lend themselves to debate and investigation? Which experiments can students complete within the resource limitations of their learning environments?

Week Topics Learning activities

1 Class display: creation of a ‘relative scale’ of particles Experiment: flame tests and spectra Simulation: atomic structure Elements and the periodic table (relative https://phet.colorado.edu/en/simulation/build-an-atom particle size; element definitions and symbols including atomic number, mass number and Data analysis: periodic trends and explanations in terms of isotopic forms; atomic spectra; electronic electronegativities and graphs of first ionisation energies of 2 configurations; periodic table patterns and elements trends) Communication: students research a useful isotope and write a media article Investigation: trends across a period or down a group of the periodic table 3 Experiment: comparison of the properties of main group and transition metals Metals (properties explained by structure; Model: properties of alloys using plasticene and sand main group versus transition metals; relative www.nuffieldfoundation.org/practical-chemistry/modelling-alloys- 4 reactivities; extraction of a metal; modification plasticine by heat; metallic nanomaterials) Observation: metallic crystals under a stereomicroscope – class comparisons Experiment: extraction of copper from a solution of a copper ore 5 Experiment: investigation of the properties of ionic compounds Ionic compounds (properties explained by Model: structures of ionic compounds 6 structure; crystal formation; uses) Experiment: simulation of crystal formation in rocks by making chocolate fudge under different temperature conditions 7 Quantifying atoms and compounds Model: visualisation of the mole though calculations (depth of a 8 (relative isotopic mass; carbon-12 standard; ‘blanket’ of a mole of marshmallows over Australia; height of a relative atomic mass; mass spectrometry; ‘tower’ made from a mole of dollar coins or sheets of A4 paper; mole concept; Avogadro constant; calculations length of time to count a mole of marbles if one was counted © VCAA 2015 91 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS

of numbers of moles of atoms in samples; every second every day until finished) molar mass of ionic compounds; empirical Calculations: worksheets related to mole and empirical formula formula) calculations Week Topics Learning activities Modelling: ball-and-stick models of simple polyatomic molecules and Materials from molecules (modelling of interactions molecular substances; polarity of molecules; Individual student hypothesis formulation and experimental 9 properties explained by structure; relative investigation: capillarity strengths of bonds; ice and water comparisons) Predict-observe-explain: investigation of volume contraction in alcohol-water mixtures 10 Carbon lattices and carbon Models: create and annotate models of carbon allotropes nanomaterials (properties explained by Student research: contemporary application of a carbon 11 structure; graphene; fullerenes; nanomaterial applications in society) nanomaterial 12 Experiment: steam distillation of eucalyptus leaf/orange peel/ti-tree Organic compounds and polymers (origin 13 leaf/cloves; method improvement by investigating different and use of crude oil and its hydrocarbon collection, heating or extraction methods components; families of hydrocarbon Modelling: organic structures and polymers compounds; organic chemistry IUPAC nomenclature; empirical and molecular Prediction: trends in melting and boiling points of a range of organic formula determinations; polymers from molecules 14 monomers; addition polymerisation of Experiment: making and modifying slime alkenes; thermosetting and thermoplastic Site tour: polymer manufacturing plant polymers; designer polymers; use of polymers in society) Problem-based learning scenario: plastic versus paper shopping bag alternatives 15 Students register an individual research question (development of a research question and aims; purpose of 16 communication and target audience and/or product; characteristics of effective science communication; investigation methodology, primary and/or secondary sources of information including surveys, interviews; 17 undertaking of investigation; analysis and evaluation of data and methods; limitations of conclusions; development of effective communication and/or product) 18 Unit revision 19

© VCAA 2015 92 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Sample Course Outline – VCE Chemistry Unit 2: What makes water such a unique chemical? Note: This is a sample guide only and indicates one way to present the content from the VCE Chemistry Study Design over the weeks in each school term. Teachers are advised to consider their own contexts in developing learning activities: Which local fieldwork sites would support learning in the topic area? Which local issues lend themselves to debate and investigation? Which experiments can students complete within the resource limitations of their learning environments?

Week Topics Learning activities 1 Experiment: comparison of specific heat capacities of water and Properties of water (melting and boiling different oils points of Group 16 hydrides; specific heat Modelling: group oral or multimodal presentation related to the 2 capacity; latent heat; applications for living things) application of latent heat in student-selected context of perspiration, kitchen chemistry, storms, climate science 3 Experiment: group-developed hypotheses to investigate different aspects of solubility Properties of water and water as a Problem-based learning: groups investigate acid rain or ocean solvent (solution processes in water of acidification effects molecular substances and ionic compounds; 4 precipitation reactions; applications in Research and experiment: electrolytes in soft drinks, mineral water everyday life) and sports drinks Hypothesis formulation and testing: How can hard water be softened? 5 Experiment: differentiation between strong and weak acids on the basis of conductivity, pH and rate of reaction with magnesium Acid-base reactions in water (Brǿnsted- Laboratory safety: relate the strength and concentration of acids and Lowry theory; polyprotic and amphoteric bases to the safety procedures for their use species; ionic equations; ionic product of Scientific skills: compare the accuracy, precision and validity of water; pH; strong and weak acids and bases; collated class measurements of the pH of a variety of everyday 6 concentrated and dilute acids and bases; solutions reactions of acids with metals, carbonates and Experiments: round-robin of acid reactions – students record results hydroxides; acid-base chemistry issue in and write equations in logbooks; annotate equations to show society) direction of proton transfer Acid-base chemistry web dilemma including social, ethical and economic implications 7 Redox reactions in water (oxidising and Experiment: metal displacement reactions and the reactivity series; 8 reducing agents; conjugate redox pairs; redox compare predictions with results reactions; reactivity series of metals; redox Chemical language development: equation-writing and annotation of chemistry issue in society) redox equations to identify direction of electron flow, oxidising © VCAA 2015 93 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS

agent, reducing agent, conjugate redox pairs 9 Media analysis: YouTube clips related to water contamination issues Water sample analysis and measurement of solubility and concentration Experiment: solubility curve of a salt (distribution of drinking water around the Data analysis: interpretation of world maps showing water world; sampling protocols; chemical distribution and quality 10 contaminants; solubility and solubility tables; Site tour: water treatment plant – infographic to link processes to relationship between temperature and solubility concepts solubility; solubility curves; solution concentration conversions) Class display: increasing salt or sugar concentrations of packaged foods 11 Experiment: Law of Conservation of Mass – tracking of mass changes 12 of chemical reactions in closed systems; model the rearrangement of atoms in the reactions 13 Analysis for salts, organic compounds and acids and bases in water (sources; Experiment: gravimetric analysis of the total chloride content of a mass-mass stoichiometry; volume-volume water sample stoichiometry; acid-base titrations; analytical Instrumental analysis – colorimetric versus instrumental analysis of techniques – colorimetry, UV-visible phosphate 14 spectroscopy, atomic absorption Acid-base titration: dilutions; preparation of a standard solution of spectroscopy, HPLC ) hydrochloric acid; analysis of a base in a water sample Calculations: mass-mass and volume-volume stoichiometry worksheets 15 Negotiation with students/class to undertake research question – laboratory investigation and/or 16 fieldwork (hypothesis formulation; determination of aims, questions and predictions; identification of independent, dependent and controlled variables; methodology and equipment list; laboratory and/or fieldwork techniques; risk 17 assessment; undertaking of experiment and/or fieldwork; analysis and evaluation of data, methods and models; limitations of conclusions; possible further investigations; poster presentation) 18 Unit revision 19

Sample Course Outline – VCE Chemistry Unit 3: How can chemical processes be designed to optimise efficiency? Note: This is a sample guide only and indicates one way to present the content from the VCE Chemistry Study Design over the weeks in each school term. Teachers are advised to consider their own contexts in developing learning activities: Which local fieldwork sites would support learning in the topic area? Which local issues lend themselves to debate and investigation? Which experiments can students complete within the resource limitations of their learning environments?

Week Topics Learning activities 1 W Observational skills: burning candle observation Predict-observe-explain: compare predicted and actual values of melting/boiling points of samples of different Obtaining energy from fuels (fuel fuels definition; combustion of fuels; ∆H; Data analysis: comparison of fuel efficiencies writing thermochemical equations; Stoichiometry: calculations related to combustion of different PV=nRT; calculations related to the 2 fuels and CO /energy produced combustion of fuels; specific heat 2 capacity) Debate: use of sugar cane for food versus for fuel Class blog: biodiesel – ‘green’ fuel or red herring? Experiment: collation of class data related to determinations of specific heat capacities of ethanol and other fuels 3 Class jigsaw: student comparison of a fossil fuel and a biofuel – criteria developed for ranking ‘best to worst’ Modelling: structures of the molecules in petrodiesel and Fuel choices (comparison of fossil fuels biodiesel and biofuels; petrodiesel and 4 biodiesel fuel comparisons) Construction: torsion viscometer for comparison of viscosities of fuels Graphic organiser: comparison of petrodiesel and biodiesel as transport fuels 5 Galvanic cells as a source of energy Experiment: observation of metal displacement reactions (redox reactions mechanisms and under a stereomicroscope 6 reactions; galvanic cells; energy Quiz: writing redox half-reactions and overall reactions transformations in direct contact chemical reactions versus galvanic Experiment: galvanic cells (including predictions made by cell reactions; use of electrochemical referring to the electrochemical series) – results series in making predictions) presented as a photo essay © VCAA 2015 95 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS

Research: infographic on a contemporary galvanic cell Experiment: simple fuel cell Fuel cells (design features; comparison Flow chart: comparison of a student-selected galvanic and a of use of fuel cells versus direct fuel 7 student-selected fuel cell combustion; comparison of fuel cells and galvanic cells) Research: short report on a contemporary fuel cell including redox reactions 8 Poster evaluation: 9 strengths/weaknesses/opportunities/threats of provided examples Practical investigation (experimental Investigation design brainstorming: two groups: ‘fuel source variables; scientific research efficiencies’, or ‘galvanic cell function’ as an extension of methodologies and ethics; data prior investigations organisation, analysis and evaluation; Test: hypothesis formulation and experimental design 10 organisation of Chemistry concepts; nature of evidence; scientific report Student investigation: negotiation, confirmation and writing conventions) materials preparation Student undertaking of investigation Reporting/poster write-up phase 11 Analogy: collision theory and Boltzmann distributions Infographic: cold/heat pack investigation and explanation Rate of chemical reactions (collision Ho Research: exothermic and endothermic reactions in theory and Maxwell-Boltzmann everyday life distributions; exothermic and endothermic reactions; energy Experiment (class data collation): effect of temperature/ 12 profile diagrams; factors affecting concentration/ surface area on the rate of a chemical reaction rate; role of catalysts in reaction chemical reactions) Analysis: Energy profile diagrams Experiment: effect of a catalyst on the rate of a chemical reaction 13 Extent of chemical reactions Experiment: hydration and dehydration of copper(II) sulfate (reversible and irreversible reactions; Experiment: Le Chatelier’s Principle and changes to a system 14 homogenous equilibria; equilibrium at equilibrium calculations; Le Chatelier’s principle; equilibrium changes represented by Quantitative chemistry: equilibrium calculations

concentration-time graphs; Case study: carbon monoxide poisoning through faulty home 15 Animation: processes occurring in an electrolytic cell Production of chemicals by electrolysis (electrolysis of molten Experiment: factors that determine the products of liquids and aqueous solutions; electrolysis of potassium iodide solution operating principles of commercial Research: infographic related to a commercial electrolytic 16 electrolytic cells; use of cell electrochemical series in making Experiment: electroplating and Faraday’s laws predictions; application of Faraday’s laws) Graphic organiser: comparison of electrolytic and galvanic cells Rechargeable batteries Quiz: rechargeable batteries/redox principles (discharging/recharging of batteries; Experiment: construction and testing of a lead-acid battery 17 redox principles; factors affecting Research: annotated diagram of a contemporary battery life) rechargeable including redox reactions 18 Unit revision 19

Sample Course Outline – VCE Chemistry Unit 4: How are organic compounds categorised, analysed and used? Note: This is a sample guide only and indicates one way to present the content from the VCE Chemistry Study Design over the weeks in each school term. Teachers are advised to consider their own contexts in developing learning activities: Which local fieldwork sites would support learning in the topic area? Which local issues lend themselves to debate and investigation? Which experiments can students complete within the resource limitations of their learning environments?

Week Topics Learning activities 1 Scientific modelling: hydrocarbons and hydrocarbon Structure and nomenclature of derivatives organic compounds (properties of the carbon atom; chiral centres and Quiz: organic compound nomenclature 2 optical isomers; cis- and trans- Think-pair-share: create and name organic molecules isomers; structures and IUPAC Summary table: L-and D-glucose comparisons naming of organic compounds) Case study: thalidomide 3 Experiment: boiling points of a series of organic compounds Categories, properties and Experiment: viscosity – bubbles and liquids 4 reactions of organic compounds Flowcharts: organic reactions (trends in boiling point and viscosity; organic reactions and pathways; Experiment: esterification 5 atom economy; percentage yield) Evaluation: ‘green’ chemistry – percentage yield or atom Ho economy? 6 Discussion: accuracy versus precision – class comparisons of 7 measures of an object’s length Case study: chemical analysis – food poisoning 8 Analysis of organic compounds Data evaluation: spectroscopy 9 (mass spectroscopy; IR spectroscopy; proton and carbon-13 Excursion: laboratory analysis techniques (chromatography, NMR; chemical analysis using IR and proton-NMR) combined spectroscopy techniques; Design, construct and test: optical device for measuring fat chromatography and HPLC; acid- content in different types of milk 10 base and redox titrations) Acid-base titration: citric acid in fruit juices Redox titration: alcohol in white wine Quantitative chemistry: instrumentation and titrations 11 Key food molecules (structures of Modelling and animations: haemoglobin © VCAA 2015 98 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS Experiment: making nylon/extraction of casein – property comparisons proteins, carbohydrates, and fats/oils; essential and non-essential Experiment: ant preferences for natural or artificial dietary components; energy content sweeteners of carbohydrates; glycogen as a Modelling: fats and oils 12 storage molecule; melting points of Experiment: melting points of triglycerides triglycerides; saturated and unsaturated fatty acids; water- Titration: degree of saturation of fats and oils soluble and non-water-soluble Media analysis: ranking ‘good’ oils vitamins) Experiment: vitamin solubilities and structures Analysis: food labels 13 Metabolism of food in the body Analysis: metabolism of a selected processed food (metabolism as a source of energy Experiment (jigsaw activity): Nuffield – measuring reaction and nutrients; enzyme function and 14 rates of catalysed reactions factors that affect action; denaturation and hydrolysis of Denaturation of egg white by CuSO4 solution proteins; hydrolysis of starch; Media file: food issues – glycemic index 15 glycemic index; hydrolysis of Evaluation: which cooking oil is best? fats/oils; oxidative rancidity; action of coenzymes) Animations of co-enzyme action: Vitamin B 16 Energy content of food (energy Experiment: glucose fermentation values of carbohydrates, proteins Design, build and evaluate: construct a simple calorimeter to and fats/oils; cellular respiration; measure the energy content of popcorn; suggest 17 calorimetry; solution calorimetry calorimeter improvements temperature-time graphs) Quantitative chemistry: energy calculations and calorimetry 18 Unit revision 19

Appendix 10: Employability skills

The VCE Chemistry study provides students with the opportunity to engage in a range of learning activities. In addition to demonstrating their understanding and mastery of the content and skills specific to the study, students may also develop employability skills through their learning activities. The nationally agreed employability skills are: Communication; Planning and organising; Teamwork; Problem solving; Self-management; Initiative and enterprise; Technology; and Learning. The table links those facets that may be understood and applied in a school or non- employment related setting, to the types of assessment commonly undertaken within the VCE study.

Assessment task Employability skills selected facets Annotations of activities Communication (writing to the needs of the audience) or investigations from a Problem solving (testing assumptions taking the context of data practical logbook and circumstances into account) Self-management (articulating own ideas and visions) Comparative analysis of Communication (sharing information; persuading effectively; scientific processes or writing to the needs of the audience) phenomena Planning and organising (collecting, analysing and organising information) Self-management (having knowledge and confidence in own ideas and visions; articulating own ideas and visions) Technology (using information technology to organise data) Data analysis Communication (using numeracy; persuading effectively; writing to the needs of the audience) Planning and organising (collecting, analysing and organising information) Problem solving (applying a range of strategies to problem solving; using mathematics to solve problems; testing assumptions taking the context of data and circumstances into account) Technology (using information technology to organise data) Evaluation of research or Communication (reading independently; writing to the needs of a case study the audience; using numeracy) Learning (being open to new ideas and techniques) Planning and organising (collecting, analysing and organising information) Problem solving (testing assumptions taking the context of data and circumstances into account) Media response Communication (listening and understanding; reading independently; writing to the needs of the audience; using numeracy; persuading effectively) Problem solving (showing independence and initiative in identifying problems and solving them; testing assumptions taking the context of data and circumstances into account) Problem-solving involving Communication (sharing information; using numeracy; chemistry concepts, skills persuading effectively) and/or issues Initiative and enterprise (being creative; generating a range of options; initiating innovative solutions) Learning (managing own learning; being open to new ideas and © VCAA 2015 100 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS techniques) Planning and organising (planning the use of resources including time management; collecting, analysing and organising information) Problem solving (developing creative, innovative solutions; developing practical solutions; showing independence and initiative in identifying problems and solving them; applying a range of strategies to problem solving; using mathematics to solve problems; testing assumptions taking the context of data and circumstances into account) Self-management (having knowledge and confidence in own ideas and visions; articulating own ideas and visions) Report Communication (sharing information; speaking clearly and (oral/written/visual/multi directly; writing to the needs of the audience; using numeracy; modal) persuading effectively) Planning and organising (collecting, analysing and organising information) Self-management (having knowledge and confidence in own ideas and visions; articulating own ideas and visions) Technology (having a range of basic information technology skills; using information technology to organise data; being willing to learn new information technology skills) Response to structured Problem solving (applying a range of strategies to solve questions problems; using mathematics to solve problems) Scientific modelling Communication (persuading effectively; sharing information) Initiative and enterprise (being creative; initiating innovative solutions) Learning (managing own learning; being open to new ideas and techniques) Problem solving (developing creative, innovative solutions; developing practical solutions; applying a range of strategies to problem solving) Planning and organising (planning the use of resources including time management) Scientific poster Communication (writing to the needs of the audience; persuading effectively; sharing information; using numeracy) Planning and organising (planning the use of resources including time management; collecting, analysing and organising information) Problem solving (using mathematics to solve problems; testing assumptions taking the context of data and circumstances into account) Self-management (articulating own ideas and visions) Technology (using information technology to organise data; being willing to learn new information technology skills) Student-designed Initiative and enterprise (being creative; generating a range of practical investigation options; initiating innovative solutions) Planning and organising (managing time and priorities – setting timelines, coordinating tasks for self and with others; planning the use of resources including time management; collecting, analysing and organising information) Problem solving (developing practical solutions; showing independence and initiative in identifying problems and solving them) Self-management (evaluating and monitoring own performance; taking responsibility) Teamwork (working as an individual and as a member of a team; knowing how to define a role as part of the team; sharing © VCAA 2015 101 VCE Chemistry Units 1 and 2: 2016–2020 ADVICE FOR TEACHERS information) Technology (having the Occupational Health and Safety knowledge to apply technology; using information technology to organise data)

The employability skills are derived from the Employability Skills Framework (Employability Skills for the Future, 2002), developed by the Australian Chamber of Commerce and Industry and the Business Council of Australia, and published by the (former) Commonwealth Department of Education, Science and Training.