Assessment of Basic Chemistry ConceptsThis instrument is based on the Chemical Concepts Inventory developed by Doug Mulford (2002). It was modified by staff at the Modeling Instruction Program in the Summer of 2009 for use with high school students. The test consists of 28 multiple choice questions. Question 29 serves to indicate that you are taking the updated version of this instrument. Carefully consider each question and indicate the one best answer for each. Several of the questions are paired. In these cases, the first question asks about a chemical or physical effect. The second question then asks for the reason for the observed effect. Record your answers on the answer sheet. DO NOT write on this copy of the test. ABCC-v2.6 1 2010 C. Between 20 and 21 pounds. Each of the answers (a). B. Water molecules evaporate from the milk and condense on the outside of the glass. C. 20 Pounds. B. What is in the bubbles in the boiling water? A. D. 4. The sum of the masses of all substances involved. The number of atoms of each type involved. Oxygen gas and hydrogen gas.1. Water molecules from the air condense onto the outside of the glass. Assume a beaker of pure water has been boiling for 30 minutes. The coldness causes oxygen and hydrogen from the air to combine on the glass forming water. Gaseous water. 21 pounds. What is the weight of the solution when 1 pound of salt is dissolved in 20 pounds of water? A. and (c) must be the same. E. Which of the following must be the same before and after a chemical reaction? A. More than 21 pounds. B. 3. 2. Heat. D. D. D. Both (a) and (c) must be the same. E. C. C. Air. ABCC-v2. B. How does most of the water get there? A. Water molecules from the milk pass through the glass and condense on the outside of the glass. The number of molecules of all substances involved. E. Oxygen gas. (b). A glass of cold milk sometimes forms a coat of water on the outside of the glass (often referred to as 'sweat').6 2 2010 . Less than 20 pounds. The circle on the left shows a magnified view of a very small portion of liquid water in a closed container.6 3 2010 . What would the magnified view show after the water evaporates? ABCC-v2. Which diagram shows the results after the mixture reacts as completely as possible according to the equation: 2S + 3O2 2SO3 6. The diagram represents a mixture of sulfur (S) atoms and oxygen (O2) molecules in a closed container.5. What is the reason for your answer to question 7? A. None of these accounts for what happens to the density. Breaking oxygen bonds. 10. Energy is released when hydrogen burns in air according to the equation 2H2 + O2 2H2O Which of the following is responsible for the release of energy? A. True B. The atoms are not destroyed. Breaking hydrogen bonds. How does the density of each half compare to the density of the original piece? A. The mass of ash is less than the match it came from. C. D. ABCC-v2. The density of each half is less than the density of the original piece. D. 11. The density of each half is the same as the density of the original piece. D. C. 9. This chemical reaction destroys matter. E. C.6 4 2010 . B. B. True or False? When a match burns. B. they are only rearranged.7. some matter is destroyed. The mass of each cubic centimeter of aluminum is unchanged. Reducing the mass of the sample reduces the density. Reducing the volume of the sample increases the density. What is the reason for your answer to question 10? A. Matter is consumed by the flame. The density of each half is greater than the density of the original piece. C. Both (a) and (b) are responsible. A. Forming hydrogen-oxygen bonds. B. False 8. A piece of aluminum is cut in half. The match weighs less after burning. B. 26.0 grams. the total weight will be: A. C.0 grams. A 1. 28.12. Iodine gas is lighter than air. filling the tube with iodine gas. C. 13. Iodine gas is less dense than solid iodine.0 grams.000 6 x 1023 ABCC-v2. E. D. B. D.000. 27. After heating. Gases rise. What is the reason for your answer to question 12? A.0 grams. 14. more than 28.6 5 2010 .000 10. Mass is conserved. less than 10 1. less than 26. B.0 grams. A gas weighs less than a solid. D. What is the approximate number of carbon atoms it would take placed next to each other to make a line that would cross this dot: A. C.0 grams.0-gram sample of solid iodine is placed in a tube and the tube is sealed after all of the air is removed. The tube and the solid iodine together weigh 27. The tube is then heated until all of the iodine evaporates. E. Both received the same amount of energy. both at 25°C. Figure 1 represents 1. Alcohol has a lower density than water. Water has a higher boiling point than the alcohol. Which of the following is true once the water and alcohol have both reached 50°C? A. C. water requires more energy. The water received more energy than the alcohol. The dots in the magnification circle represent the sugar molecules. are heated at the same rate under identical conditions. B.0 liter (L) of a solution of sugar dissolved in water. What is the reason for your answer to question 16? A. 17. the water molecules have not been shown. Figure 2 16. B. D.6 6 2010 .15. Equal volumes of water and alcohol. Figure 1 Which of the following represents the view after 1. The alcohol received more energy than the water. C. ABCC-v2. D. In order to simplify the diagram. After 3 minutes the temperature of the alcohol is 50°C. It took 5 minutes for the water to reach 50°C. Both liquids had a temperature change of 25°C. It is impossible to tell from the information given. For the same temperature change.0 L of water was added to the beaker? (Figure 2). B. The nail flakes away. E. decreases. less than the original nail. It is impossible to predict. more than the original nail. B. B. There is the same amount of salt in less water. The salt evaporates along with the water.) The concentration of salt in solution A. The iron from the nail is destroyed. B. Salt does not evaporate and is left in solution. The water is allowed to evaporate until the volume of solution is half the original volume. C.6 7 2010 . More solid salt forms on the bottom of the beaker. one should find that the rusty nail weighs: A. C.18. D. Rusting makes the nail lighter. 19. If an iron nail were placed in a beaker and allowed to rust for a month. C. 21. What is the reason for your answer to question 18? A. Salt is added to water and the mixture is stirred until no more salt dissolves. Some solid salt does not dissolve and settles to the bottom of the beaker. stays the same. the same as the original nail. D. D. C. Rust contains iron and oxygen. 20. (Assume the temperature remains constant. The flaky rust weighs less than iron. increases. ABCC-v2. Iron combines with oxygen and water from the air to form rust. as shown in the figure below. What is the reason for your answer to question 20? A. i only. ii.22. Melting point of 113°C. The temperature stays constant for a while. then rises (A) B. ii and iii only. if any.41°F) in five minutes. E. B. iv only. it becomes easier to heat as it warms up. the energy supplied goes into overcoming attractive forces in the solid. then slower (C) D. The temperature rises more slowly at first. None of these descriptions would apply. Density of 2.6 8 2010 . B.1 g/cm3. heats a mixture of ice and water from 0ºC to 5ºC (32°F . The following describe a sample of solid sulfur: i. The temperature rises more rapidly at first. All of these descriptions would apply. iv. which provides a constant rate of heat output. crystalline solid. An electric heater. 23. E. then faster (B) C. Choose the graph which best describes the change in temperature of the water (T) as a function of time (t). Combines with oxygen to form sulfur dioxide Which. At first. iii. C. Brittle. D. The motion of water molecules in ice is restricted. of these descriptions apply to one single atom of sulfur obtained from the sample? A. The heat output increases the thermal energy of the system at a constant rate. The temperature rises at a constant rate (D) 24. D. What is the reason for your answer to question 23? A. neglecting any heat loss to the environment: A. Very cold things absorb heat more quickly. ABCC-v2. It is hard to warm up something cold. C. then slower (C) D.A small block of solid aluminum is taken out of the freezer and heated by an electric heater. D.41°F). E. The temperature rises at a constant rate (D) 26. which provides a constant rate of heat output. The temperature stays constant for a while. C. It is hard to warm up something cold. 25. it becomes easier to heat as it warms up. ABCC-v2. then rises (A) B. Very cold things absorb heat more quickly. At first. then faster (B) C. Choose the graph which best describes the change in the average temperature of the aluminum (T) as a function of time (t). neglecting any heat loss to the environment: A. The heat output increases the thermal energy of the system at a constant rate. The temperature rises more rapidly at first. The temperature rises more slowly at first. from -5°C to 5°C (23°F . What is the reason for your answer to question 25? A. the energy supplied goes into overcoming attractive forces in the solid.6 9 2010 . The motion of the aluminum particles in the solid is restricted. B. C. the solution bubbles vigorously. Please fill in (A) on the answer sheet. What is the reason for your answer to question 27? Styrofoa m Copper HCl(aq) H2O(l) A. E. ABCC-v2. the system gives off energy to the surroundings and the temperature of the system decreases. Copper is a good conductor of heat. Twater > 20ºC . In order for the chemical reaction to take place. A decrease in temperature in one place is compensated by an increase in another place. That will help us know which test version you are using. The solution in the copper cup cools during the reaction. causing energy to flow from the outside water through the copper. is placed in a styrofoam cup containing 200 mL of water (see diagram). the temperature of the solution drops to 10ºC. 27. HCl(aq). whereas styrofoam conducts heat poorly. 29. 28.6 10 2010 . D. In a heat-releasing reaction. and by the end of the reaction. What is the temperature of the water in the styrofoam cup several minutes after the reaction is completed ? A. B. B. When baking soda (NaHCO3) is added to the HCl solution in the copper cup. C. Chemical energy is converted into thermal energy during the reaction. Twater = 20ºC .A copper cup containing 100 mL of hydrochloric acid. Both containers are initially at 20ºC. Twater < 20ºC . energy must be transferred from the water in the styrofoam cup to the solution in the copper cup.