Unit 10 Review

1. Unit 10 Review Energy

2. 1. The direct change of a substance from a solid to a gas is called ____. A. vaporization B. condensation C. melting D. sublimation

3. 2. What is a key difference between a liquid and a gas? A. Particles are moving faster in a liquid B. Particles are moving faster in a gas C. The particles have higher KE in a liquid D. The particles are held in place in a gas

4. 3. Which are the first particles to evaporate from a liquid? A. The ones with the lowest KE B. The ones with the highest KE C. The ones at the surface D. Both B and C

5. 4. If a liquid is sealed in a container and kept at constant temperature, how does its vapor pressure change over time? A. It increases B. It decreases C. Increases at first, then is constant D. None of the above

6. 5. What causes gas pressure in a container, such as a helium balloon? • The particles bouncing off the walls of the balloon B. The particles colliding with one another C. The particles evaporating D. All of the above

7. 6. When the vapor pressure of a liquid is equal to the atmospheric pressure, the liquid ____. A. Evaporates B. Boils C. Melts D. Sublimes

8. 7. The escape of molecules from the surface of a liquid is known as ____. A. Vaporization B. Boiling C. Deposition D. Evaporation

9. 8. Which of the following will evaporate the fastest? A. Water at 20oC B. Water at 40oC C. Water at 60oC D. All will evaporate at the same pace

10. 9. The average kinetic energy of water molecules is greatest in which of the following? A. Steam at 110oC B. Liquid water at 373 K C. Solid substance at -15oC D. All are the same

11. 10. What is the pressure (in kPa) when a liquid is boiling at its normal boiling point? A. 101.3 kPa B. 1 kPa C. 50 kPa D. .0573 kPa

12. 11. What happens to the rate of evaporation of a liquid as the liquid is cooled? A. The rate increases B. The rate decrease C. The rate stays the same D. Not enough information

13. 12. Why does a liquid’s rate of evaporation increase when the liquid is heated? A. Particles have lower amount of energy B. Particles are colliding less often C. Particles have higher amount of energy • Particles can overcome attractive forces holding them together • Both C and D

14. 13. What happens to the average kinetic energy of the particles in a sample of matter as the temperature of the sample is increased? A. It increases B. It decreases • No change

15. 14. In a dynamic equilibrium between the liquid state and the gas state, what is true about the rate of evaporation? A. It equals the rate of sublimation B. It equals the rate condensation C. It equals the rate of melting D. Particles are gaining energy

16. 15. Consider an iron cube and an aluminum cube. If the two cubes were at the same temperature, how would the average kinetic energy of the Fe particles compare with Al? A. They would be the same B. Fe’s KE would be higher C. Al’s KE would be higher D. Can not be determined

17. 16. What is the pressure (in atm) at the normal boiling point of water? A. 1 atm B. 101.3 atm C. 0 atm D. 73.5 atm

18. 17. How many phases of water are in equilibrium at the triple point? A. 0 B. 1 C. 2 D. 3

19. 18. A process that absorbs heatis called a(n) ____ process. A. exothermic B. endothermic C. calorimetry D. enthalpy

20. 19. A piece of metal is heated, then submerged in cool water. The temperature of the water____ and the temperature of the metal ____. A. Increases, increases B. Decreases, decreases C. Increases, decreases D. Decreases, increases

21. 20. The process used to measure the amount of heat gained or lost during a chemical or physical process is called A. Specific heat B. Enthalpy C. Calorimetry D. Quantity of heat

22. Answers 1. D 9. A 17. D 2. B 10. A 18. B 3. B 11. B 19. C 4. C 12. E 20. C 5. A 13. A 6. B 14. B 7. D 15. A 8. C 16. A