Practice Identifying Parts Of The Scientific Method

NAME: ______Midterm Review

Unit 1 – Science Review Topics

QUALITATIVE VS. QUANTITATIVE WORK SHEET Determine which of the following statements are quantitative and which are qualitative. 1. ______The cup had a mass of 454 grams. 2. ______The temperature outside is 250 C. 3. ______It is warm outside. 4. ______The tree is 30 feet tall. 5. ______The building has 25 stories. 6. ______The building is taller than the tree. 7. ______The sidewalk is long. 8. ______The sidewalk is 100 meters long. 9. ______The race was over quickly. 10. ______The race was over in 10 minutes.

Practice Identifying Parts of the Scientific Method

Directions: The following are experimental scenarios. Read the experiments and then identify the components of the scientific method by completing the graphic organizer provided.

Experimental Scenario #1 A student investigated the effect of radiation on the germination of bean seeds. He thought that exposure to radiation would limit the seeds ability to germinate (grow) much like ultra-violet light causing skin cancer. Three hundred seeds were soaked in distilled water for one hour. They were then divided into three groups. One group was placed in a microwave oven on high for three seconds. Another group was microwaved on high for six seconds. The last group was not microwaved. The seeds were then planted in three separate flats and given the same amount of water. The seeds were then planted in three separate flats and given the same amount of water. The flats were placed in a location with a constant temperature of approximately 27 degrees Celsius. Each day for two weeks the number of seeds that germinated each group was recorded.

Total Number of Bean Seeds Germinated after Microwave Radiation

Three Seconds of Radiation Six Seconds of Radiation No Radiation 54 26 88

Analysis of Experimental Scenarios – Graphic Organizer –

Problem/Observation:

Question:

Hypothesis:

Experiment:

Procedures

Independent Variable

Dependent Variable

Controls

Control Group

Experimental Group(s) Conclusions:

Conversions-Metric to Metric Conversion between the different units within the metric system is accomplished by using the ‘Quick Conversion Line’ to move the decimal point the appropriate number of places in the appropriate direction.

kilo hecto deka Unit deci centi milli 1000 100 10 meter 0.1 0.01 0.001 liter gram 1

How can you remember this? Kids Having Doughnuts Usually Drink Chocolate Milk

In-class examples: 58.9 kg = g 9,852,614 mm = km

852,614 mL = L .007621 kL = L

3 meters = ______centimeters 10 kilometers = ______meters

15,050 milligrams into grams 3,264 milliliters = ______liters

Scientific Notation

Part A: Express each of the following in standard form.

1. 5.2 x 103 5. 3.6 x 101

2. 9.65 x 10–4 6. 6.452 x 102 3. 8.5 x 10–2 7. 8.77 x 10–1

4. 2.71 x 104 8. 6.4 x 10–3

Part B: Express each of the following in scientific notation.

1. 78,000 5. 16

2. 0.00053 6. 0.0043

3. 250 7. 0.875

4. 2,687 8. 0.012654

Unit 2 – Scientific Measurement

1. Give the number of significant figures in each of the following.

a) 10.0005 g ______

b) 0.003423 mm ______

2. Determine the answer for each of the following. Be sure to use the correct number of significant figures.

a) 27.34 b) 2.8023 6.90 - 4.762 + 13.124

c) 0.32 x 14.50 x 120 = d) 24.1 / 0.005 =

3. Round each of the following to 3 significant figures. 707.5 ______2,301.2 ______

0.0003350 ______10.26730 ______

18.95 x 1021 ______NAME: ______Unit 3 – Matter and Change

1. Provide at least 2 characteristics of solids.

2. Provide at least 2 characteristics of liquids.

3. Provide at least 2 characteristics of gases.

In the diagram below, compare solids, liquids, and gases. Where one or more circles overlap, list the ways that those states of matter are alike. Where the circles do not overlap, list the ways that each of these states of matter is unique. Solids Liquids

Gases % by mass = (mass element/mass compound) x 100 % by mass (law of definite proportions)

1. A 25.3g sample of an unknown compound contains 0.8g of oxygen (O). What is the percent by mass of oxygen in the compound?

2. 28.2g of carbon monoxide (CO) is formed when 8.57g of oxygen (O) reacts with carbon (C). What is the percent by mass of the carbon in carbon monoxide?

MATCHING

_____1. A phase change in which energy is A. Plasma absorbed from its surroundings. B. Gas _____2. Matter in which state are vibrating in a fixed location. C. Solid

_____3. The most common type of matter in D. Sublimation the universe. E. Liquid _____4. The phase change in which a solid goes directly to a gas without becoming a liquid. F. Endothermic

_____5. In this phase change the arrangement of G. Vaporization particles becomes very orderly. H. Freezing _____6. The phase change in which a substance goes from a liquid to a gas.

_____7. It has a definite volume but no definite shape.

_____8. It will take the shape of its container, and expand to fill the available space. Classify each of the following as elements (E), compounds (C) or Mixtures (M). Write the letter X if it is none of these.

___Diamond (C) ___Sugar (C6H12O6) ___Milk ___Iron (Fe)

___Air ___Sulfuric Acid (H2SO4) ___Gasoline ___Electricity ___Krypton (K) ___Bismuth (Bi) ___Uranium (U) ___Popcorn

___Water (H2O) ___Alcohol (CH3OH) ___Pail of Garbage ___A dog

___Ammonia (NH3) ___Salt (NaCl) ___Energy ___Gold (Au) ___Wood ___Bronze ___Ink ___Pizza

___Dry Ice (CO2) ___Baking Soda (NaHCO3)___Titanium (Ti) ___Concrete

Match each diagram with its correct description. Diagrams will be used once.

A B C D E

___1. Pure Element – only one type of atom present.

___2. Mixture of two elements – two types of uncombined atoms present.

___3. Pure compound – only one type of compound present.

___4. Mixture of two compounds – two types of compounds present. ___5. Mixture of a compound and an element.

Column A lists a substance. In Column B, list whether the substance is an element (E), a compound (C), a Heterogeneous Mixture (HM), or a Solution (S). (Remember a solution is a homogeneous mixture.) In Column C, list TWO physical properties of the substance.

Column B Column C Column A 1. Summer Sausage 2. Steam 3. Salt Water 4. Pencil lead (Pb) 5. Dirt 6. Pepsi 7. Silver (Ag)

8. Toothpaste (Na2HPO4) 9. A burrito 10. Italian Dressing 11. Chicken Soup 12. Lemonade

DENSITY: D = M/V Find the unknown quantity: a) d = 3 g/mL b) d = ? c) d = 0.5 g/mL V = 100 mL V = 950 mL V = ? M = ? M = 95 g M = 20 g

PHYSICAL PROPERTY CHEMICAL PROPERTY 1. observed with senses 1. indicates how a substance 2. determined without destroying matter reacts with something else 2. matter will be changed into a new substance after the reaction

Identify the following as a chemical (C) or physical property (P): ______1. blue color ______8. melting point ______2. density ______9. reacts with water ______3. flammability (burns) ______10. hardness ______4. solubility (dissolves) ______11. boiling point ______5. reacts with acid ______12. luster ______6. supports combustion ______13. odor ______7. sour taste ______14. reacts with air

PHYSICAL CHANGE CHEMICAL CHANGE 1. a change in size, shape, or state 1. a change in the physical and 2. no new substance is formed chemical properties 2. a new substance is formed Identify the following as physical (P) or chemical (C) changes. _____1. NaCl (Table Salt) dissolves in water. ______9. Milk sours. _____2. Ag (Silver) tarnishes. ______10. Sugar dissolves in water _____3. An apple is cut. ______11. Wood rots. _____4. Heat changes H2O to steam. ______12. Pancakes cook. _____5. Baking soda reacts to vinegar. ______13. Grass grows. _____6. Fe (Iron) rusts. ______14. A tire is inflated. _____7. Alcohol evaporates . ______15. Food is digested. _____8. Ice melts. ______16. Paper towel absorbs water.

Unit 4 – Atomic Theory

12. Complete the chart:

Number of Number of Number of Mass Atomic Element Protons Neutrons Electrons Number Number

Lithium (Li)

Argon (Ar) 41

47 109

Lead (Pb)

19 Tantalum 73 (Ta)

Chromium 24 (Cr)

Uranium 149 (U)

Tungsten (W)

COMPLETE THE CHART

CHARGE LOCATION

ELECTRON

NEUTRON

PROTON

Given the relative abundance of the following naturally occurring isotopes of oxygen, calculate the average atomic mass of oxygen: oxygen-16: 99.760% oxygen-17: 0.037% oxygen-18: 0.204% A research team has just discovered a new element called Likhitium. Now, they need to determine the average atomic mass in order to complete an entry for the periodic table. Given the following relative abundances, calculate the average atomic mass of Likhitium.

Likhitium-138: 44.7% Likhitium-140: 00.5% Likhitium-139: 52.3% Likhitium-141: 02.5%

Elements, Compounds, and Mixtures Elements, Compounds, and Mixtures Classify each of the pictures below by placing the correct label in the blanks below: A= Element D= Mixture of compounds B= Compound E= Mixture of elements and compounds C= Mixture of elements Each circle represents an atom and each different color represents a different kind of atom. If two atoms are touching then they are bonded together. 1. Write orbital filling diagrams, electron configurations, and electron dot diagrams for the following elements.

Table: Element Orbital Filling Diagram Electron Configuration Electron Dot Diagram a. Aluminum b. Carbon c. Oxygen d. Magnesium e. Fluorine f. Tellurium

History of the Atom John Dalton (1766 – 1844): John Dalton was an English chemist. His ideas form the atomic theory of matter. Here are his ideas.  All elements are composed (made up) of atoms. It is impossible to divide or destroy an atom.

 All atoms of the same elements are alike. (One atom of oxygen is like another atom of oxygen.)

 Atoms of different elements are different. (An atom of oxygen is different from an atom of hydrogen.)

 Atoms of different elements combine to form a compound. These atoms have to be in definite whole number ratios. For example, water is a compound made up of 2 atoms of hydrogen and 1 atom of oxygen (a ratio of 2:1). Three atoms of hydrogen and 2 atoms of oxygen cannot combine to make water.

1. What is the name of John Dalton’s theory? ______

2. What are elements made of? ______3. An atom of hydrogen and an atom of carbon are ______. 4. What are compounds made of? ______5. The ratio of atoms in HCl is: a) 1:3 b) 2:1 c) 1:1

J. J. Thompson (Late 1800s): J. J. Thompson was an English scientist. He discovered the electron when he was experimenting with gas discharge tubes. He noticed a movement in a tube. He called the movement cathode rays. The rays moved from the negative end of the tube to the positive end. He realized that the rays were made of negatively charged particles – electrons. 1. What did J.J. Thompson discover? ______2. What is the charge of an electron? ______3. What are cathode rays made of? ______4. Why do electrons move from the negative end of the tube to the positive end? ______5. What was Thompson working with when he discovered the cathode rays? ______

Lord Ernest Rutherford (1871 – 1937): Ernest Rutherford conducted a famous experiment called the gold foil experiment. He used a thin sheet of gold foil. He also used special equipment to shoot alpha particles (positively charged particles) at the gold foil. Most particles passed straight through the foil like the foil was not there. Some particles went straight back or were deflected (went in another direction) as if they had hit something. The experiment shows:  Atoms are made of a small positive nucleus; positive nucleus repels (pushes away) positive alpha particles

 Atoms are mostly empty space

1. What is the charge of an alpha particle? ______

2. Why is Rutherford’s experiment called the gold foil experiment? ______3. How did he know that an atom was mostly empty space? ______4. What happened to the alpha particles as they hit the gold foil? ______5. How did he know that the nucleus was positively charged? ______

Niels Bohr (Early 1900s): Niels Bohr was a Danish physicist. He proposed a model of the atom that is similar to the model of the solar system. The electrons go around the nucleus like planets orbit around the sun. All electrons have their energy levels – a certain distance from the nucleus. Each energy level can hold a certain number of electrons. Level 1 can hold 2 electrons, Level 2 - 8 electrons, Level 3 - 18 electrons, and level 4 – 32 electrons. The energy of electrons goes up from level 1 to other levels. When electrons release (lose) energy they go down a level. When electrons absorb (gain) energy, they go to a higher level. 1. Why could Bohr’s model be called a planetary model of the atom? ______

______2. How do electrons in the same atom differ? ______

______3. How many electrons can the fourth energy level hold? ______

4. Would an electron have to absorb or release energy to jump from the second energy level to the third energy level? ______5. For an electron to fall from the third energy level to the second energy level, it must ______energy.