Mr. Cozart Chapter 12 Test

Multiple ChoiceIdentify the letter of the choice that best completes the statement or answers the question.

1. Compared with the particles in a gas, the particles in a liquida. have more energy. b. are larger. c. move around less. d. are farther apart.

2. The compressibility of a liquid is generallya. less than that of a gas. b. more than that of a gas. c. equal to that of a gas. d. zero.

3. The lower mobility of particles in a liquid compared with those in a gas results in the liquid beinga. less disordered. b. lower in density. c. colder. d. higher in energy.

4. Which of the following statements about freezing is NOT correct?a. All liquids freeze. b. Water freezes at 0ºC. c. Not all liquids freeze. d. Some liquids freeze at room temperature.

5. Compared with the particles in a liquid, the particles in a solid usually area. higher in energy. b. closer together. c. more massive. d. more fluid.

6. The intermolecular forces between particles in a solid area. weaker than those in a gas. b. too weak to hold the particles in fixed positions. c. stronger than those in a liquid. d. of different types than those in a liquid.

7. The compressibility of solids is generallya. lower than the compressibility of liquids and gases. b. higher than the compressibility of liquids. c. about equal to the compressibility of liquids. d. zero.

8. The rate of diffusion in solids is very low because thea. particles are not free to move about. b. surfaces of solids usually contact gases. c. attractive forces are weak. d. melting points are high.

9. The difference between crystalline and amorphous solids is determined bya. temperature changes. b. pressure when the substances are formed. c. amount of order in particle arrangement. d. strength of molecular forces.

10. Compared with a crystalline solid, the particles in an amorphous solida. occur in a random pattern. b. occur in a definite, three-dimensional arrangement. c. consist of molecular sheets. d. have a more complex unit cell.

11. Which of the following is an amorphous solid?a. ice b. diamond c. graphite d. glass

12. Which of the following is not correct about crystalline solids?a. They can maintain a definite shape without a container. b. They can exist as single crystals. c. Their particles are held in relatively fixed positions. d. They are geometrically irregular.

13. Which of the following is a crystalline solid?a. a plastic milk container b. a quartz rock c. a glass bottle d. a three-dimensional glass cube

14. What type of crystal consists of positive metal cations surrounded by valence electrons that are donated by the metal atoms and belong to the crystal as a whole?a. ionic b. covalent network c. metallic d. covalent molecular

15. What is the total three-dimensional array of points that describes the arrangement of the particles of a crystal?a. unit cell b. crystal lattice c. diffraction pattern d. crystalline system

16. Which of the following is NOT a property of covalent network crystals?a. high conductivity b. hardness c. high melting point d. brittleness

17. What is the smallest portion of a crystal lattice that reveals the three-dimensional pattern?a. unit cell b. crystal structure c. coordinate system d. crystalline symmetry

18. A system is in equilibrium whena. no physical or chemical changes are occurring. b. the physical changes counteract the chemical changes. c. opposing physical or chemical changes occur at equal rates. d. only physical changes are occurring.

19. Whenever a liquid changes to a vapor, ita. absorbs heat energy from its surroundings. b. is in equilibrium with its vapor. c. is boiling. d. is condensing.

20. If the concentration of vapor above a liquid remains zero, thena. no condensation can occur. b. the rate of evaporation is high. c. the rate of condensation is high. d. no further evaporation can occur.

21. When does the concentration of a vapor decrease?a. when the rate of evaporation decreases b. when the temperature remains constant c. when the liquid phase is warmed d. when the rate of condensation exceeds the rate of evaporation

22. If the temperature of a liquid-vapor system at equilibrium is reduced, thea. concentration of the vapor will decrease. b. rate of evaporation will increase. c. equilibrium is unaffected. d. percentage of liquid in the system will decrease.

23. If the temperature of a liquid-vapor system at equilibrium increases, the new equilibrium condition willa. have a lower concentration of vapor. b. have an increased vapor pressure. c. not have equal rates of condensation and evaporation. d. be larger in volume.

24. The equilibrium vapor pressure of a liquid isa. the same for all liquids. b. measured only at 0ºC. c. constant for a particular liquid at all temperatures. d. the pressure exerted by a vapor in equilibrium with its liquid at a given temperature.

25. At a given temperature, different liquids will have different equilibrium vapor pressures becausea. the energy of the particles is the same for different liquids. b. diffusion rates differ for the liquids. c. the attractive forces between the particles differ among liquids. d. they cannot all be in equilibrium at once.

26. The equilibrium vapor pressure of water isa. constant at all temperatures. b. specific for any given temperature. c. unrelated to temperature. d. inversely proportional to the temperature.

27. If the equilibrium vapor pressure is falling,a. the rate of evaporation is increasing. b. the liquid has begun to boil. c. no further condensation can take place. d. the temperature of the liquid is decreasing.

28. At pressures greater than 760 mm Hg, water will boil ata. a temperature higher than 100ºC. b. a temperature lower than 100ºC. c. 100ºC. d. 4ºC.

29. Why would a camper near the top of Mt. Everest find that water boils at less than 100ºC?

a. There is greater atmospheric pressure than at sea level. b. The flames are hotter at that elevation. c. There is less atmospheric pressure than at sea level. d. The atmosphere has less moisture.

30. During boiling, the temperature of a liquida. remains constant. b. increases. c. decreases. d. approaches the standard boiling point.

31. During the process of freezing, a liquida. loses kinetic energy. b. loses potential energy. c. gains potential energy. d. gains kinetic energy.

32. The triple point of a substance is the temperature and pressure conditions at whicha. density is greatest. b. states of a substance coexist at equilibrium. c. equilibrium cannot occur. d. kinetic energy is at a minimum.

33. What is the critical pressure?a. the pressure at which all substances are solids b. the pressure at which the attractive forces in matter break down c. the highest pressure under which a solid can exist d. the lowest pressure under which a substance can exist as a liquid at the critical temperature

34. The angle between the two H–O bonds in water is evidence ofa. sp3 hybridization. b. sp2 hybridization. c. 2s orbitals. d. 2p orbitals.

35. Why are water molecules polar?a. They contain two kinds of atoms. b. The electrons in the covalent bonds spend more time closer to the oxygen nucleus. c. The hydrogen bonds are weak. d. They have covalent bonds.

36. If the water molecules were nonpolar, it is likely thata. water would be a solid at room temperature. b. water would be flammable. c. water would be a gas at room temperature. d. the hydrogen bonding would be stronger.

37. The electronegativity difference between oxygen and hydrogen results in the water molecule beinga. flammable. b. polar. c. ionically bonded. d. linear.

38. What is the freezing point of water at standard pressure?a. –10ºC b. 0ºC c. 4ºC d. 32ºC

39. Water changes from liquid to solid at 0ºC and what pressure?a. 1 atm b. 706 mm Hg c. –1 atm d. 1.436 mm Hg

40. When water is warmed from its freezing temperature to its temperature of maximum density, ita. contracts. b. expands. c. maintains a constant volume. d. increases in weight.

41. Why doesn't water in lakes and ponds of temperate climates freeze solid during the winter and kill nearly all the living things it contains?a. Water is colorless. b. Ice floats. c. The molar heat of fusion of ice is relatively low. d. Water contracts as it freezes.

42. What is the characteristic of water that makes steam useful for household heating systems?a. high molar heat of vaporization b. low molar heat of fusion c. high density d. low boiling point

43. The molar heat of vaporization of water is 40.79 kJ at 100ºC. What is the heat of vaporization of 1 g of water?a. 40.79 J b. 80.3 J c. 500. J d. 2.26 kJ

44. The standard molar heat of vaporization for water is 40.79 kJ/mol. What mass of steam is required to release 500. kJ of heat energy upon condensation?a. 221 g b. 325 g c. 1130 g d. 1660 g

Short Answer

45. Explain how evaporation occurs.

46. How are vaporization and evaporation related?

47. How is a solid formed?

Mr. Cozart Chapter 12Answer Section

MULTIPLE CHOICE

1. C2. A3. A4. C5. B6. C7. A8. A9. C

10. A11. D12. D13. B14. C15. B16. A17. A18. C19. A20. A21. D22. A23. B24. D25. C26. B27. D28. A29. C30. A31. B32. B33. D34. A35. B36. C37. B38. B39. A40. A41. B

42. A43. D44. A

SHORT ANSWER

45. The particles in a liquid have different kinetic energies. Particles on the surface of the liquid that have higher-than-average energies can overcome the intermolecular forces that bind them to the liquid. These particles escape the liquid and enter the gas state.

46. Vaporization is the process by which a liquid or solid changes to a gas. Evaporation is a form of vaporization, and more specifically, the process by which particles escape from the surface of a nonboiling liquid and enter the gas state.

47. When a liquid is cooled, the average energy of its particles decreases. When the energy is low enough, attractive forces pull the particles into a more orderly arrangement. This orderly arrangement is a solid.