Syllabus AP Chemistry

Syllabus AP ChemistryPeter G. Atkinson Kennebecasis Valley High School Quispamsis, New Brunswick, Canada School EnvironmentKennebecasis Valley High School is a public high school with grades 9-12, located in the town of Quispamsis, a suburb of Saint John, New Brunswick. The community is middle class with strong commitment to education, including high expectations for post-secondary study. The enrollment is approximately 1150 students. The Advanced Placement program is in its fifteenth year at the school. There are eight AP courses currently running with about 150 exams written each year. Course Sequence Leading to AP ChemistryStudents who enroll in AP Chemistry are most likely to do so in their grade twelve year of high school. They will have completed the enriched grade eleven and the enriched grade twelve courses in Chemistry prior to the AP Chemistry course. Students will usually have completed the AP Physics course in their grade eleven-year. All of the topics of AP Chemistry have been covered in the grade 11 and 12 courses but not in the depth that is required. The AP course gives the opportunity to study these topics in greater depth and to do more involved laboratory work. Class Size, Selection, SchedulingThe class size is usually 16-20 students. Students are required to complete two courses in Chemistry with a minimum of 85 in the grade twelve course before being accepted into the AP course.The school schedule is based upon a two-semester term with students taking five courses per semester for a total of ten courses in a year. The classes are 60 minutes in length for 18 weeks and a three hour Lab per week. TextsZumdahl, Steven S. and Zumdahl, Susan A. Chemistry, 8th ed., Brooks/Cole Cengage Learning, 2010.Hall, J.F.and Little, John G. AP Experimental Chemistry, 8th ed., Brooks/Cole Cengage Learning, 2010. Course OutlineThe AP Chemistry course consists of 65 to 70 classes before the AP exam(depending on the date of the exam) and 15 to 20 classes after the exam. The class begins to meet the last week in January and continues until the middle of June. The class periods are 60 minutes in length with a 3-hour lab done once per week. The topics are a more in-depth review of the topics covered in the Chemistry 111 and 121 courses.Curricular Requirement 1: Students and teachers use a recently published college-level chemistry textbook.The main text used in the course is Chemistry, 8th ed., Brooks/Cole Cengage Learning, 2010 by Zumdahl, Steven S. and Zumdahl, Susan A. Curricular Requirement 2: The course is structured around the enduring understandings within the big ideas as described in the AP Chemistry Curriculum Framework.This course is structured around the 6 big ideas and the big ideas which will be covered in the chapters in the Zumdahl text will be stated.Big Idea 1: The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions. (Structure of Matter) Chapter 2: Atoms, Molecules, and Ions Chapter 3: Stoichiometry Chapter 7: Atomic Structure and PeriodicityBig Idea 2: Chemical and physical properties of materials can be explained by the structure and the arrangement of atoms, ions, or molecules and the forces between them. (Matter – characteristics, states and forces of attraction) Chapter 4: Types of Chemical Reactions and Solution Stoichiometry Chapter 5: Gases Chapter 8: Bonding: General Concepts Chapter 9: Covalent Bonding: Orbitals Chapter 10: Liquids and Solids Chapter 11: Properties of SolutionsBig Idea 3: Changes in matter involve the rearrangement and/or reorganization of atoms and/or the transfer of electrons. (Chemical Reactions) Chapter 3: Stoichiometry Chapter 4: Types of Chemical Reactions and Solution Stoichiometry Chapter 6: Thermochemistry Chapter 18: ElectrochemistryBig Idea 4: Rates of chemical reactions are determined by details of the molecular collisions. (Rates of chemical reactions) Chapter 12: Chemical KineticsBig Idea 5: The laws of thermodynamics describe the essential role of energy and explain and predict the direction of changes in matter. (Thermodynamics) Chapter 6: Thermochemistry Chapter 17: Spontaneity, Entropy, and Free EnergyBig Idea 6: Any bond or intermolecular attraction that can be formed can be broken. These two processes are in a dynamic competition, sensitive to initial conditions and external perturbations. (Equilibrium) Chapter 13: Chemical Equilibrium Chapter 14: Acids and Bases Chapter 15: Acid-Base Equilibria Chapter 16: Solubility And Complex Ion Equilibria Curricular requirement 3: Students are provided with opportunities to meet the learning objectives within each of the big ideas as described in the AP Chemistry Curriculum Framework. These opportunities must occur in addition to those with laboratory investigations.Learning Objective within Big Idea 1Learning objective 1.20 The student can design, and/or interpret data from, an experiment that uses titration to determine the concentration of an analyte in a solution. [See SP 4.2, 5.1; Essential knowledge 1.E.2]Students will be asked to determine the concentration and pH of an unknown when presented with data from a titration experiment. Students will also be expected to design an experiment to determine the concentration of an unknown substance. Students will complete a series of questions found in the text on page 738 from Q 49-62.Learning Objective within Big Idea 2Learning objective 2.21 The student is able to use Lewis diagrams and VSEPR to predict the geometry of molecules, identify hybridization, and make predictions about polarity. [See SP 1.4; Essential knowledge 2.C.4]Students will complete Lab exercise 13: Molecular Geometry and VSEPR. From this exercise students build molecules then draw Lewis diagrams and then use VSEPR to predict the geometry and identify hybridization. Finally they will have to make predictions about polarity. Learning Objective within Big Idea 3Learning objective 3.4 The student is able to relate quantities (measured mass of substances, volumes of solutions, or volumes and pressures of gases) to identify stoichiometric relationships for a reaction, including situations involving limiting reactants and situations in which the reaction has not gone to completion. [See SP 2.2, 5.1, 6.4; Essential knowledge 3.A.2]Students presented with a scenario similar to the situation described on page 107 of the text will be able to determine the limiting reactant. The example in the texts involves the making of sandwiches. Student would then be given data from a chemical equation and be able to state the limiting reactant and determine how much product will be formed. Students would be able to identify stoichiometric relationships in an equation (measured mass of substances, volumes of solutions, or volumes and pressures of gases) and be able to solve for the requested quantity. See Questions on pages 123, 124, 173 and 227 of text. A series of questions will be given from these pages. Questions from the text will be given on the concentration of reactants and products in reactions that do not go to completion. See text page 631 to 634.Learning Objective within Big Idea 4Learning objective 4.2 The student is able to analyze concentration vs. time data to determine the rate law for a zeroth-, first-, or second-order reaction. [See SP 5.1; Essential knowledge 4.A.2, connects to 4.A.3]Learning objective 4.3 The student is able to connect the half-life of a reaction to the rate constant of a first- order reaction and justify the use of this relation in terms of the reaction being a first-order reaction. [See SP 2.1, 2.2; Essential knowledge 4.A.3] Students will demonstrate knowledge of Table 12.6 on page 562 of the text:Order Zero First Second Rate Law: Rate = k Rate = k[A] Rate = k[A]2 Integrated Rate Law: [A] = -kt + [A]0 ln[A] = -kt + ln[A]0 1/[A] =kt + 1/[A]0Plot needed to give a straight line: [A] versus t ln[A] versus t 1/[A] versus tRelationship of Rate Constant to the slope of straight Line: Slope = -k Slope = -k slope = kHalf-Life: t ½ = [A]0/2k t ½ = 0.693/k t ½ = 1/k[A]0Students when presented with concentration and time data as in the questions on page 581 and 582 will be able to determine the order of a reaction.Students when given a set of experimental data for a first-order reaction will be able to connect the half-life to the rate constant. See questions page 583 of the text.Learning Objective within Big Idea 5Learning objective 5.7 The student is able to design and/or interpret the results of an experiment in which calorimetry is used to determine the change in enthalpy of a chemical process (heating/cooling, phase transition, or chemical reaction) at constant pressure. [See SP 4.2, 5.1; Essential knowledge 5.B.4]Students use a given set of data to predict and compare the temperature changes from a series of chemical reactions including acid-base, phase changes, precipitation, redox and combustion. Also assorted questions found on page 277 and 278 of the text can be completed.Learning Objective within Big Idea 6Learning objective 6.4 The student can, given a set of initial conditions (concentrations or partial pressures) and the equilibrium constant, K, use the tendency of Q to approach K to predict and justify the prediction as to whether the reaction will proceed toward products or reactants as equilibrium is approached. [See SP 2.2, 6.4; Essential knowledge 6.A.3]Students when given a set of initial conditions will predict whether the reaction will proceed toward products or reactants as equilibrium is approached. The student will complete exercises 13.39 to 13.42 in the text on page 631. Curricular Requirement 4: The course provides students with the opportunity to connect their knowledge of chemistry and science to major societal or technological components (e.g. concerns, technological advances, innovations) to help them become scientifically literate citizens.As a starting point students in the class will review the Chemical Connections in the course text. From this each student selects a different Chemical Connection to do more research on including at least three references to the original literature on the topic. The student will summarize on a poster and give a class oral presentation on what they have learned. Curricular requirement 5: Students are provided the opportunity to engage in investigative laboratory work integrated throughout the course for a minimum of 25% of instructional time, which must include a minimum of 16 hand-on laboratory experiences that emphasize guided-inquiry investigations to support the learning objectives listed within the AP Chemistry Curriculum Framework.Curricular Requirement 6: Students are provided opportunities to practice guided inquiry. At minimum, six of the required 16 labs are conducted in a student-directed format.The Laboratory ProgramThe laboratory program is based on traditional activities using full-size equipment. The laboratory text is Hall, J.F.and Little, John G. AP Experimental Chemistry, 8th ed., Brooks/Cole Cengage Learning, 2010. The labs are scheduled once per week and are three hours in duration. The labs that are completed in the course are given below in the course outline.The lab component of the course will include three hours of lab time for every five hours of class time. The lab will therefore consist of 37.5% of the course time.The focus of the labs will be on guided inquiry and will incorporate the seven Science practices. Six labs will be modified to fit the criteria of the Herron Model and to adhere to the standards found in Inquiry and the National science Education Standards: A Guide for Teaching and Learning (2000) An example of a guided inquiry lab which will be used is found in appendix 1When the teacher edition of the AP Chemistry lab manual is available it may be used instead of modifying the current labs. The manual will feature 16 classroom-tested, guided-inquiry labs designed to advance students’ inquiry skills and their ability to apply science practices. The labs align with the new curricular requirements and support the learning objectives identified in the AP Chemistry Curriculum Framework and best practices endorsed in America's Lab Report. The following seven Science Practices will be incorporated in the labs.Science Practices for AP® ChemistryScience Practice 1: The student can use representations and models to communicate scientific phenomena and solve scientific problems.Science Practice 2: The student can use mathematics appropriatelyScience Practice 3: The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP courseScience Practice 4: The student can plan and implement data collection strategies in relation to a particular scientific question. [Note: Data can be collected from many different sources, e.g., investigations, scientific observations, the findings of others, historic reconstruction, and/or archived data. Science Practice 5: The student can perform data analysis and evaluation of evidenceScience Practice 6: The student can work with scientific explanations and theories.Science Practice 7: The student is able to connect and relate knowledge across various scales, concepts, and representations in and across domains.In the list of labs The following is the list of labs that could be done or modified to fit with guided inquiry if the AP Chemistry lab manual is not available. An example of a guided type inquiry lab from Saint Francis Xavier University is found in Appendix 1 that would replace Lab 9 Calorimetry.The list of Labs comes from Hall, J.F.and Little, John G. AP Experimental Chemistry, 8th ed., Brooks/Cole Cengage Learning, 2010.In the following list of labs the Science practices that are emphasized are given in brackets. Obviously more Science Practices will be used in each lab put the point of emphasis will be explained.1. Lab 2: The Formula of a Hydrate The properties and characteristics of several ionic hydrates will be studied. (S.P. 2.2, 5.2: The student can apply mathematical routines to quantities that describe natural phenomena; The student can refine observations and measurements based on data analysis.2. Lab 6: Analysis by Oxidation-Reduction Titration A redox reaction will be used in the titration analysis of an iron compound. ( S.P. 2.1, 2.2 The student can justify the selection of a mathematical routine to solve problems.; The student can apply mathematical routines to quantities that describe natural phenomena3. Lab 7: Molar Mass by Vapor Density: The Dumas Method The molar mass of two volatile liquids will be determined by measuring what mass of vapour of the liquid is needed to fill a flask of known volume at a particular temperature and pressure. ( S.P. 2.1, 2.2 The student can justify the selection of a mathematical routine to solve problems.; The student can apply mathematical routines to quantities that describe natural phenomena4. Lab 8: Heats of Reaction and Hess’s Law Hess’s Law of Additivity of Reaction Enthalpies will be verified. (S.P. 2.2, 7.1 The student can apply mathematical routines to quantities that describe natural phenomena; The student can connect phenomena and models across spatial and temporal scales.)5. Lab 9: Analysis by Calorimetry Calorimetry will be used to determine the stoichiometry of a reaction (S.P. 2.1, 7.1 The student can justify the selection of a mathematical routine to solve problems; The student can connect phenomena and models across spatial and temporal scales.)6. **Lab 13: Molecular Geometry and VSEPR (used as an alternative activity not a lab) (S.P. 1.1, 1.4 The student can create representations and models of natural or man-made phenomena and systems in the domain; The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively.)7. Lab 14: Thin-Layer Chromatogrphy A separation of a mixture of coloured organic dyes will be done by thin-layer chromatography. Varying solvent composition will be investigated to determine the effectiveness on separation. (S.P. 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices.)8. Lab 15: Heat of Fusion and Freezing Point Depression The molar heat of fusion and the molal freezing point depression will be determined for lauric acid. (S.P. 2.2, 6.1 The student can apply mathematical routines to quantities that describe natural phenomena; The student can justify claims with evidence.)9. Lab 16: Synthesis and Analysis of Aspirin Aspirin will by synthesized and the purity of the product will be determined by colourimetic means. (S.P. 7.1, 7.2 The student can connect phenomena and models across spatial and temporal scales; The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas.)10. Lab 19: Hydrolysis of t-Butyl Chloride: A Kinetics Investigation The rate law and the specific rate constant for a chemical reaction will be determined. (S.P. 4.1,4.3, 5.1 The student can justify the selection of the kind of data needed to answer a particular scientific question; The student can collect data to answer a particular scientific question; The student can analyze data to identify patterns or relationships.)11. Lab 20: Investigating Acid-Base Equilibria The pH and solubility behavior of selected chemical systems will be observed. (S.P. 6.2, 6.3 The student can construct explanations of phenomena based on evidence produced through scientific practices; The student can articulate the reasons that scientific explanations and theories are refined or replaced.)12. Lab 21: Titration Curves The pH versus volume curves for three combinations of strong and weak acids will be made. A diprotic acid will be included. (S.P. 5.1, 6.1 The student can analyze data to identify pattern or relationships; The student can justify claims with evidence.)13. Lab 22: Acids, Bases, and Buffers In this experiment, a study of the properties of acidic and basic substances will be made, using indicators and a pH meter to determine pH. A buffered system will be prepared by half-neutralization and the properties of the buffered system will be compared to those of a nonbuffered medium. (S.P. 3.1, 3.2 The student can pose scientific questions; The student can refine scientific questions)14. Lab 24: Le Chatelier’s Principle The shifts in equilibrium position predicted by Le Chatelier’s principle will be observed. The shifts will be interpreted in terms of the concentration changes. (S.P. 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models.)15. Lab 25: Determination of an Equilibrium Constant The value of an equilibrium constant will be determined experimentally by colourimetric means. (S.P. 2.2, 7.1 The student can apply mathematical routines to quantities that describe natural phenomena; The student can connect phenomena and models across spatial and temporal scales.)16. Lab 26: Determination of a Solubility Product Constant The Ksp of calcium iodate will be determined using gravimetric titration. (S.P. 2.2 3.1 The student can apply mathematical routines to quantities that describe natural phenomena; The student can pose scientific questions.)17. Lab 27: Electrochemical Cells Several voltaic cells will be constructed and their properties studied. (S.P. 6.2,The student can construct explanations of phenomena based on evidence produced through scientific practices.)18. Lab 28: Electrolysis and Electrolytic Cells The products of three different electrolytic cell systems will be examined. (S.P. 7.1 The student can connect phenomena and models across spatial and temporal scales.)Curricular Requirement 7: The course provides opportunities for students to develop and record evidence of their verbal, written and graphic communication skills through laboratory reports, summaries of literature or scientific investigations, and oral, written and graphic presentations.Component 7a: Through laboratory reports, the course provides multiple opportunitiesfor students to develop their written and graphic communication skills.The laboratory report is expected to conform to University standard and the school follows the same marking scheme as the local University (The University of New Brunswick, Saint John Campus) Three general themes will be looked at in the written work: i) Do you have all the information and understand it? ii) Is it communicated clearly (this includes grammar, spelling and units)? iii) Is the required format/order followed (or marks will be deducted)?The format is as follows:Laboratory Title Name Partner’s Name Lab Day/TimePurpose: This is completed after reading over the assigned laboratory, and before the laboratory periodPrelab Assignment: as requiredTabulation of Data: Record data in ink. Each new piece of data is recorded immediately in your data table.Procedure: The following format should be followed for the procedure. 1. Write in the third person, using the past tense. Be concise 2. Describe observations briefly in brackets, at the appropriate point in the procedure. 3. Start sentences with words, not with numbers Your procedure must be in your own words, and tell exactly what you did.Calculations: Must be neat and organized. When running duplicates, each trial is to be calculated separately and the final results averaged or marks will be deducted. Any graph must be completed on graph paper and included in this section.Conclusion: State what was learned from the work. Include how you have, or have not, met the objective. Ensure you include any calculated results, and where possible, compare them with the known value. Describe the product, e.g. caffeine (white powder), when appropriateSources of Error: Suggest reasonable causes which could account for discrepancies between your results and the expected (or known) results. Do not include every conceivable error. Ensure that it is reasonable or probable that the error(s) influenced the results. Suggest ways to prevent (or minimize) these errors in the future.Assigned Problems/Questions: There are assigned problems/questions included in the laboratory manual. These constitute part of the mark for the lab and must be completed and submitted with the report.** ALL REPORTS ARE KEPT IN A LAB NOTEBOOK**Other Notes about lab reportsPrelab assignments must be done prior to the lab. The lab write-up is due one week after the lab is completed. Labs are done on Mondays a rough copy of the lab may be submitted by E-mail for evaluation on Thursday and the final copy submitted on the following Monday as well as this weeks prelab exercise.Component 7b: Through summaries of literature and scientific investigations, the course provides multiple opportunities for students to develop their verbal, written and graphic communication skillsAn example of Component 7b is covered in Curricular Requirement 4. As a starting point students in the class will review the Chemical Connections in the course text. From this each student selects a different Chemical Connection to do more research on including at least three references to the original literature on the topic. The student will summarize on a poster and give a class oral presentation on what they have learned.Component 7c: Through oral, written, or graphic presentations, students use their communication skills to present information.As indicated in the lab report section each student should present laboratory data in graphical format where appropriate. Component 7c is covered in component 7b by doing a poster and an oral presentation.Final RemarksKeep in mind that all students have completed the majority of topics in their previous two Chemistry courses and this course constitutes an in depth review. This is the reason why the course can be done in such a rapid fashion. Appendix 1Explorations in Thermochemistry - An Inquiry Lab for First Year Inorganic Chemistry © Nancy Crowe November 2001 Submitted as part of Education 427, St Francis Xavier University Table of Contents Page Student Handout Foreword to Students 1 Objectives 2 Pre-Lab Exercises 2 Introduction and Guided Activities 2 Safety Considerations 4 Procedure 5 Report 6 Notes to Instructors Purpose of Inquiry Lab Activities 7 Supervising Inquiry-based Activities 7 Marking and Evaluating Inquiry-based Activities 8 Notes on Thermochemistry 10 Resources Used 12 1 An Inquiry Activity in Thermochemistry Foreword to Students: “Real” scientists push the frontier of scientific knowledge by asking questions; the ‘how, why, when, what if...’ questions of life form the basis of inquiry. Scientific inquiry is really an open, sometimes unstructured process used to discover the nature of a phenomenon or obtain data and evaluate the newly-acquired data in the context of present theories and knowledge. Remember that scientific knowledge is dynamic! This lab activity departs from the more conventional “cook book” formats used in most Introductory Chemistry labs where the objective is clearly defined, the steps of the procedure are listed sequentially, and the expected outcome, observation, data, etc. is implied. Too often that is like having the fun part of the exploration and thinking planned for you! The purpose of this and other inquiry-based activities is to give you freedom to explore and develop your own ability to examine and think about scientific concepts. (Among teaching professionals this is called ‘critical thinking’.) Inquiry involves some of the following: asking questions, formulating hypothesis, designing experiments, collecting data, analyzing and interpreting data, and drawing conclusions. Other techniques that may be used in inquiry are: predicting, observing, measuring and/or describing, and explaining. Inquiry lab activities in science fall into two categories: guided inquiry and free inquiry. In the guided inquiry the instructor provides several templates that the student scientist might explore. In free inquiry the student is free to explore at random within the topic. As this may well be your first-ever inquiry lab activity, we will provide you with some suggestions in the style of a “guided inquiry”. A good approach is to predict what you think will occur before starting the experiment based on what you know of present scientific knowledge. Observe the actual phenomenon, collect the data, etc. Then analyze the data and explain your findings. In inquiry labs there is no “right or wrong” approach, no “right or wrong” finding. Both your professor and Lab Instructor will try to guide your inquiry into thermochemistry by asking relevant questions (but seldom by providing answers!). Ideally you would have an unlimited amount of time for your exploration; however, given the constraints of the timetable, we are going to request that you complete your inquiry in the 3 hours allotted for your lab session. As always, we are concerned about your safety. Please ensure that you read and follow the safety precautions noted below. MSDS sheets are also provided in the lab room for your use (or you can access them before the lab session in Cox 220 or at http://hazard.com/msds/ ). 2 Thermochemistry Objectives1: At the end of this activity you should: ! Be able to explain what you did in the investigation and why you chose to do that ! Be able to comment scientifically on the meaning of the data and observations you obtained ! Understand and explain your findings in the context of others’ work and theories in the field of thermochemistry ! Reflect on whether inquiry learning suits your learning style Pre-lab Exercise: | Read this lab handout | In keeping with scientists’ need to prepare themselves by reading in their field, read the section on Thermochemistry in your textbook, particularly sections 6.1, 6.2, 6.4, 6.6 and 6.7. | Think about what specific aspect you and your partner would like to explore | Sketch a rough flowchart for how you might approach this (this may be modified once you start your investigation – scientists need to respond interactively as they build on the knowledge base) | It is your responsibility to familiarize yourself with the MSDS sheets of the chemicals you will be working with and to take appropriate precautions. Introduction: Thermochemistry is a study of the change in heat as a result of chemical reactions. You are already familiar with exothermic and endothermic reactions from our examination of factors affecting chemical equilibria. Your personal day-to-day existence depends on the chemical energy released from the molecular bonds of your daily diet. Calorimetry is the technique used to measure the amount of energy contained in molecular bonds. Although it is possible to assemble a small calorimeter, time constraints do not allow us to do this right now. Instead you will select one of the general areas below and examine exothermic or endothermic dissolution or dilution reactions. 1 In maintaining consistency, I will use headings and the format used in the CS100 Lab Manual. 3 Possible Investigation #1: Exothermic or Endothermic????? In your reading perhaps you have encountered suggested activities that study whether ionic compounds like CaCl2• 2 H2O, NH4Cl, NaNO3, NaOH, KOH, NaCl form exothermic or endothermic reactions as part of their dissolution in water. Which are this, on dissolution in water, form exothermic and which endothermic reactions? Does the amount of heat exchanged depend on the amount of the compound? On the amount of water? What is the relationship (is it linear, exponential, etc.)? Do only ionic compounds dissolve with an evolution or absorption of heat? What about molecular compounds like sucrose, glucose, aspartic acid? Does the presence of water in the crystal (i.e., a hydrate) affect the type of reaction (-)H; +)H) and amount of heat (Q) in the system? (You might try BaCl2• 2 H2O, FeSO4• 7 H2O, CoCl2 • 6H2O, CuSO4• 5 H2O.) [SAFETY: To prevent excessive heat generation, Do NOT exceed a ratio of 20 g salt or alkali to 100 mL water. Do not touch the an uninsulated container surface as it may be 70BC.] Possible Investigation #2: Endothermic Reactions Some of you who are keen athletes may have first-hand experience with ‘cool packs’ used to treat some injuries to minimize swelling. How do these work? What are their chemical constituents? In water, sodium chloride, sodium carbonate, as well as ammonium nitrate all exhibit exothermic reactions. Is the cooling effect instantaneous or is there a time delay in the cooling action? Confirm that the change in temperature ()H) is negative. How efficient are one or more of these solutes in terms of drop in temperature per g of salt? (In other words, what is the heat of reaction, Q?) [SAFETY: Handle sample containers with care; some surfaces will be cold.] 4 Possible Investigation #3: Exothermic Reactions Others of us may be more familiar with the convenience of ‘mitt warmers’ .... those delightful little commercial packages that once the seal is cracked, a warmth is generated to warm our skihill cooled hands. You may wish to explore the exothermic reactions of calcium chloride dihydrate, anhydrous magnesium sulfate, potassium hydroxide, or sodium hydroxide when dissolved in water. What is the change in temperature ()H)? Which of these generates the most heat on a per mass basis ( BC/g)? Is there a time delay in the heating action? Are there localized spots of heat in the solvent? How efficient are these in terms of drop in temperature per g of salt? (In other words, what is the heat of reaction, Q?) Would the dissolution of potassium hydroxide and/or sodium hydroxide be the same in anhydrous methanol? In 50% methanol in water? [SAFETY: To prevent excessive heat generation, Do NOT exceed a ratio of 20 g salt or alkali to 100 mL water or methanol.] Possible Investigation #4: Heats of Dilution We have already in previous labs admonished ourselves to always remember “add the acid to the water”. Why is this? When added at the same concentration to water, do all acids generate the same amount of heat? You may wish to try concentrated hydrochloric acid, nitric acid, acetic acid. [SAFETY: Always add the acid slowly to the water with stirring. To prevent excessive heat generation, Do NOT exceed a ratio of one volume of the concentrated acids to one volume of water.] Safety Considerations: In keeping with our CS100 Lab Policy, you MUST wear eye protection and lab coats when in the Please note the safety precautions associated with the Investigation you and your partner have selected. These are designed to prevent excessive heat build-up that might result in spontaneous boiling or bumping of the solutions. It is your responsibility to familiarize yourself with the MSDS sheets of the chemicals you will be working with and to take appropriate precautions. If you have ANY doubts of the safety of what you are proposing to do, please check with the Lab Instructor before starting!! 5 Procedure: This is yours to design! You may (or may not) wish to keep in mind the use of blanks, controls, standards, etc. The Lab Instructor will make the following available to you in the lab: CaCl2• 2 H2O BaCl2• 2 H2O FeSO4• 7 H2O CoCl2 • 6H2O CuSO4• 5 H2O sucrose glucose aspartic acid NH4Cl NH4NO3 NaCO3 MgSO4 (anhydrous) NaNO3 NaOH (solid pellets) KOH NaCl K Cl H Cl (concentrated; 12.1 M) CH3COOH (concentrated; 17.4 M) HNO3 (concentrated; 15.9 M) CH3COONa Thermometers styrofoam cups glass stirring rods and other stirring devices rings and ring stands graph paper (10 divisions in 1 cm) CRC Handbook of Chemistry and Physics Merck Index various Intro Chemistry and Physical Chemistry resource books and texts You will also have access to the glassware and equipment in your CS100 lab lockers 6 Report: Please prepare a Memo Format Lab Report (pp 6-7; CS100 Lab Manual). For this memo, you may use up to 3 pages. To meet the objectives of this inquiry activity you should include the following: 1) An explanation of what aspect of thermochemistry you and your partner chose to investigate (heat of dissolution, heat of dilution, characteristics of exothermic or endothermic reactions, etc). Why were you intrigued by this topic? Based on your previous knowledge, what did you predict before starting the investigation? 2) A brief outline of how you approached the investigation - what samples did you use, what measurements/observations did you record? Did you use blanks, etc? 3) How meaningful were the results and observations that you made? (Were they consistent and reproducible? Were you able to control all of the factors and parameters or were your results possibly influenced by uncontrolled factors?) 4) Interpret and explain your findings in the context of other thermochemistry knowledge. Do your findings have any real-life relevance? 5) If you were doing further work or repeating the present investigation, what (if anything) would you do differently? Why? 6) Include your personal feelings, observations, and comments on this inquiry activity. ( Did you enjoy the departure from a cookbook approach? Would you enjoy more of these in the future? Did it make you think and learn in different ways? What did you discover about yourself as a scientist-in-training and/or as a learner?) 7 Instructor’s Guide to Inquiry Labs in Introductory Chemistry Purpose: Current thinking in university instruction is placing an increasing emphasis on critical thinking and inquiry-based learning. Inquiry-based lab activities are meant to help students follow a POE sequence: 1) thinking about and predicting the anticipated phenomenon or outcome based on their present knowledge 2) observing (asking questions, formulating hypothesis, designing experiments, collecting data, analyzing data), and 3) explaining in the form of describing and/or drawing conclusions thereby adding to their understanding of the concept(s). As noted in the Foreword to the Students, this inquiry lab activity is modeled after a guided inquiry – where the students are given some suggested starting points and investigation topics. As students become familiar and comfortable with an inquiry-style approach to learning, the use of free inquiry would be appropriate. Inquiry- based learning, a type of discovery learning, is student centered. While it is student centered, it nevertheless is demanding on the instructor. While there is less overt instructor control, the instructor can expect to deal with more unexpected student queries. Instructors are well advised to anticipate some of the possible questions as part of a more flexible instructional approach. Students will need to be guided with well designed questions. (This will not be easy or as tody as conventional university labs. Jerome Bruner has commented that knowing is a messy business and education is a risky business. I think that you will find that this applies to inquiry-based learning.) Supervising an Inquiry-based Lab: Inquiry labs require an open, nonjudgemental learning environment. Given the co-operative nature of this thermochemistry lab it is important that the room be free from criticism and sarcasm from either the Lab Instructor or the other students. Students need to have the space to make errors and ‘failures’ and the freedom to revise and repeat their experiment. They also need access to resources (texts, reference books) while in the lab. They ideally would have unlimited time to work through their investigation(s). Given the freedom and unpredictable nature of inquiry-based lab activity, there is an increased concern for safety. Scanning the draft flow charts submitted by the students at the beginning of the lab session can help alert the instructor to any unpredicted safety hazards. There is also an onus on the student to know the safety hazards associated with each chemical they chose to use. In inquiry-based labs, the Lab Instructor should use questioning to move students’ thinking along. Remember to allow 3-5 seconds minimum response time when asking questions. Questions might be divergent or convergent. In discovery style learning environments divergent questions, with no right or wrong answer, are especially useful and they promote critical thinking and synthesis. For example, divergent questions might include: 8 Predictions: “What do you already know about...?” Experimental design: “How would you design an experiment to determine or test this?” Results: “What have you found out about....?” “What have you done so far? What have you found out so far?” “How did the ___ affect ....?” “What did you find out about the relationship between ___ and ...?” Convegent questions encourage the student to analyze their situation. By their nature, convergent questions generally have one or two limited responses. They might be similar to the following. Predictions: “What factor affects ____?” Experimental design: “What would the blank include?” Results: “From what you discovered about___, what would you predict would happen when...?” During the inquiry lab remember that your role is to help the students discover – not to the dull or diminish the thrill of the light bulb moment. One desired outcome from an inquiry lab is to help build up the students’ self-confidence in their ability to “do science”. Evaluation and Marking: The students’ evaluation should be based not on their final outcome but on the whole process they followed. They need to be encouraged with a sense of achievement in their discoveries. This is an opportunity for them to develop an “oeuvre” - a “work” that they can and should be proud of. The ruberic below is suggested for the evaluation of the student reports. 1) An explanation of what aspect of thermochemistry was chosen for the investigation. 1 point - A simple statement of what factors were manipulated 2 points - Statement of the factors studied and the predictions made 3 points - Clear statement of what was investigated stated in scientific terms (heat of dissolution, heat of dilution, etc.) with all factors identified and predictions identified 2) A brief outline of the experimental approach used 1 - 3 points based on the appropriateness and complexity of the design 9 3) Ability to interpret results and observations 1 point - Statement of results 2 points - Statement of results with some interpretation; attention to blanks, reproducibility 3 points - Results (including blanks, reproducibility) are interpreted in the context of present knowledge and everyday life; how one would do it differently in the future 4) Metacognition - 1 point - comments on this inquiry activity (likes, dislikes) 2 points - observations/comparison to more traditional lab activities 3 points - observations on the activity as well as some comments on their personal learning experience (metacognition) 10 Notes on Thermochemistry: By convention, exothermic reactions are assigned a negative )H (enthaply) By the same convention, endothermic reactions are positive )H (enthaply) The heat of reaction, Q, is given by Q = Cm)T where C is the heat capacity of water (8.18 Joules/g@C), m is the mass of the water used and )T is the change in temperature. Assume a density of 1.00 g/cm3. Dissolution reactions Exothermic calcium chloride dihydrate 1-2 °C for 1 g in 30 mL water sodium hydroxide pellets + 42 °C for 20 g in 100 mL water; heats up quicker than KOH potassium hydroxide pellets + 28 °C for 20 g in 100 mL water sodium hydroxide + 35 °C for 20 g in 100 mL 100% methanol; dissolves slower than NaOH in water and slower than KOH in methanol potassium hydroxide + 45°C for 20 g in 100 mL 100% methanol; dissolves quicker than NaOH in methanol sodium hydroxide 60 °C for 20 g in 100 mL 50% methanol in water; dissolves more quickly than when in pure methanol anhydrous magnesium sulfate 3°C for 3 g in 100 mL water 10°C for 8 g in 100 mL water Endothermic sodium chloride 2 °C for 1 g in 30 mL water ammonium chloride 1 °C for 1 g in 30 mL water sodium nitrate 3 °C for 1 g in 30 mL water ammonium nitrate 3 °C for 3 g in 100 mL water 6 °C for 8 g in 100 mL water 11 Heat of Dilution hydrochloric acid 10-15 °C increase for 50 mL in 50 mL water nitric acid 40 °C increase for 50 mL in 50 mL water; when added as 25 mL + 25 mL the increase was 30°C acetic acid very little for 50 mL in 50 mL water sulfuric acid too exothermic for use; added in 1 mL increments 20 Ml to 100 Ml water increased the temperature 60 °C!! Hand warmers contain iron powder, salt, activated charcoal, cellulose and water of course. 12 Resources used in preparing this Inquiry Activity: Burner, J. (1996). The culture of education. Cambridge, Massachusetts: Harvard University Press. Connelly, F. M., Wahlstron, M.W., Finegold, M., & Elbaz, F. (1977). Enquiry teaching in science: A handbook for secondary science teachers. Toronto, Ontario: Ontario Institute for Studies in Education. Ebenezer, J.V. & Haggerty, S. M. (1999). Becoming a secondary science school science teacher. Upper Saddle River, New Jersey: Merrill, an imprint of Prentice Hall. Trowbridge, L.W., Bybee, R.W., & Powell, J.C. (???). Teaching secondary school science: Strategies for developing scientific literacy. Upper Saddle River, New Jersey: Merrill, an imprint of Prentice Hall.

Syllabus AP Chemistry

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