UNIT 5 GAS LAWS

1. A gas is compressed and then cooled to its original temperature. Compared to the original conditions the molecules now

(A)move faster.

(B)move slower.

(C)are farther apart.

(D)are closer together.

(E)have contracted in proportion to the pressure applied.

2. Which statement best accounts for the fact that gases can be greatly compressed?

(A)Molecules occupy space.

(B)The collisions of molecules are elastic.

(C)Molecules of gases are in constant motion.

(D)The molecules of a given gas are identical.

(E)Molecules of gases are relatively far from each other.

3. The gaseous molecules that have the greatest average velocity at 150 C are represented by

Atomic Molar MassesC12.0 gmol1F19.0 gmol1H1.0 gmol1N14.0 gmol1O16.0 gmol1

(A)O2(B)F2(C)H2(D)N2

(E)H2O

4. Which is a basic assumption of the kineticmolecular theory?

(A)Particles are in random motion.

(B)Particles undergo inelastic collisions.

(C)Particles lose energy with an increase in velocity.

(D)Particles travel faster as the temperature decreases.

(E)Particles lose energy when the temperature increases

5. How does the average kinetic energy (KE) of hydrogen molecules compare with that of oxygen molecules when both gases are at 25 C?

(A)They have equal KEs.

(B)The KE of hydrogen is 1/4 as great.

(C)The KE of hydrogen is 1/16 as great.

(D)The KE of hydrogen is 4 times as great.

6. Equal volumes of oxygen, carbon dioxide, and methane under the same conditions of temperature and pressure contain the same number of

(A)atoms.(D)electrons.

(B)molecules.(E)neutrons.

(C)protons.

7. Gases may be most easily liquefied by

(A)raising the temperature and lowering the pressure.

(B)raising the pressure and lowering the temperature.

(C)lowering both the temperature and pressure.

(D)raising both the temperature and pressure.

(E)lowering the temperature and keeping the presure unchanged

8. One liter of a certain gas has a mass of 4 g at STP. From this fact, it follows that

(A)the gas is helium.

(B)the molar mass of the gas is 4 gmol1.

(C)the molar mass of the gas is 89.6 gmol1

(D)6 1023 molecules of the gas have a mass of 4 g.

(E)there are two atoms in each molecule of the gas.

9. One liter of oxygen at STP contains approximately the same number of molecules as

(A)2 L of He at STP.(D)1/5 L of CH4 at STP.

(B)1/3 L of O3 at STP.(E)250 mL of NH3 at STP.

(C)l L of CO2 at STP.

10. A sample of sulfur dioxide gas has a mass of 16 g. The mass of the same number of molecules of nitrogen gas is

Atomic Molar MassesN14.0 gmol1O16.0 gmol1S32.0 gmol1

(A)7 g(B)14 g(C)16 g(D)28 g

(E)56 g

11. According to the Avogadro Principle, one liter of gaseous hydrogen and one liter of gaseous ammonia contain the same number of

(A)atoms at standard conditions.

(B)molecules at all conditions.

(C)molecules only at standard conditions.

(D)atoms if conditions in both containers are the same.

(E)molecules if conditions in both containers are the same.

12. Which is STP?

(A)0 C and 76 mmHg(D)100 C and 76 cmHg

(B)0 K and 76 mmHg(E)273 K and 760 mmHg

(C)0 K and 760 mmHg

13. In the experimental graph, the extrapolated line intersects the horizontal axis at about 280 C. Which term is applied to this value ?

(A)triple point(C)freezing point

(B)absolute zero(D)critical temperature

14. At the same temperature and pressure, which sample of gas contains the same number of molecules as one liter of oxygen, O2?

(A)one liter of helium, He

(B)two liters of neon, Ne

(C)three liters of carbon dioxide, CO2

(D)two liters of hydrogen, H2

15. At very low temperatures, the measured volume of a gas is slightly smaller than the volume calculated from the gas laws. Which is the best explanation?

(A)The gas molecules have lost some of their elasticity.

(B)The molecules have become smaller at the lower temperatures.

(C)The molecules exert attractive forces on each other.

(D)The molecules have a finite volume that cannot be compressed.

16. At constant volume, why does the pressure of a sample of gas increase as the temperature increases?

(A)The molecules move faster.

(B)The molecules become larger.

(C)The molecular collisions become more elastic.

(D)The molecules have less free space in which to move

17. The molecules of an ideal gas would

(A)all be diatomic.

(B)attract one another more strongly as the pressure increases.

(C)attract one another more strongly as the temperature increases.

(D)have negligible size and exert no attraction on one another.

18. Each of three identical containers holds a mole of gas, all at the same temperature.

Which gas exerts the greatest pressure? Assume ideal behavior.

(A)CH4

(B)O2

(C)SO2

(D)They all exert the the same pressure.

19. A weather balloon contains 12 L of hydrogen at 740 mmHg pressure. At what pressure in mmHg will the volume become 20 L (temperature constant)?

(A)370(B)444(C)760(D)1230

(E)1480

20. A gas occupies a 1.5 L container at 25 C and 2.0 atm. If the gas is transferred to a 3.0 L container at the same temperature, what will be the new pressure?

(A)l.0 atm(B)2.0 atm(C)3.0 atm(D)4.0 atm

(E)5.0 atm

21. Which curve shows the relationship between the volume of an ideal gas (at constant pressure) and its temperature in kelvins?

(A)A(B)B(C)C(D)D22. A fixed volume of oxygen gas, O2, exerts a pressure of 1.00 atm at a temperature of 25 C. What is the pressure of the gas when it is heated to 100 C?

(A)0.250 atm(C)2.50 atm

(B)1.25 atm(D)4.00 atm

23. Which curve represents the relationship between the volume of an ideal gas and its temperature in kelvins at constant pressure?

(A)(C)

(B)(D)

24. 100 mL of a gas measured at l36.5 C and a pressure of 380 mmHg has at standard conditions a volume of

(A)100 mL(D)400 mL

(B)200 mL(E)500 mL

(C)300 mL

25. One liter of gas at STP has a mass of 0.18 g. The molar mass of the gas is approximately

(A)0. 18 g(B)0.36 g(C)2.00 g(D)4.00 g

(E)22.40 g

26. A 31 cm3 sample of gas is collected at 37 C and 720 mmHg. What is its volume at 17 C and 580 mmHg?

(A)23 cm3(B)27 cm3(C)36 cm3(D)41 cm3

27. How many moles of a gas are contained in a 100.0 l flask at 2.00 atm and 327C ?

(A) .612 moles (B) .333 moles(C) 4.06 moles (D) 9852 moles

28. What will be the volume of 4.00 moles of CO at 27.0C and 2280 Torr?

(A) .0474 liters(B) 2.96 moles(C) 22.4 moles(D) 32.8 moles

29. 7 g of a gas occupies 11.2 L at one atmosphere pressure and 546 K. The gas could be

(A)CO(B)Ar(C)O2(D)CO2(E)NH3

30. What is the density of SO2 at STP?

Atomic Molar MassesO16 gmol1S32 gmol1

(A)0.72 gL1(D)18.7 gL1

(B)1.43 gL1(E)64.0 gL1

(C)2.86 gL1

31. One liter of oxygen is collected by displacement of water. The barometric pressure, corrected for vapor pressure, is 782 mmHg, and the room temperature is 21 C. The volume of oxygen at STP is

(A)1000 mL

(B)1000 mL

(C)1000 mL

(D)1000 mL

(E)1000 mL

32. A vessel contains 2.50 mol of oxygen gas, 0.50 mol of nitrogen gas, and 1.00 mol of carbon dioxide gas. The total pressure is 2.00 atm. The partial pressure exerted by the oxygen in the mixture is

(A)1.25 atm (D)2.00 atm

(B)1.50 atm (E)2.50 atm

(C)1.66 atm

33. What is the partial pressure of the oxygen, O2(g), in a container holding 2.0 mol of oxygen, O2(g), and 3.0 mol of nitrogen, N2(g) if the total pressure is 800 mm Hg?

(A)800 mmHg(D)400 mmHg

(B)530 mmHg(E)320 mmHg

(C)480 mmHg

34. A sample of air at 740 mmHg contains 210 cm3 oxygen, O2, 780 cm3 nitrogen, N2, and 10 cm3 other gases. What is the partial pressure of the oxygen, O2, in mmHg?

(A)78(B)155(C)310(D)580

UNIT 6 CONDENSED STATE OF MATTER/SOLUTIONS

35. The curve that represents most closely the solubility of a gas in a liquid is,

(A)A(B)B(C)C(D)D

36. Bubbles rise in a newly opened bottle of a carbonated beverage. This action is explained by the fact that carbon dioxide is less soluble in water when

(A)pressure is increased.

(B)pressure is reduced.

(C)temperature is increased.

(D)temperature is reduced.

(E)liquid carbon dioxide evaporates.

37. In general, the solubilities of gases in water

(A)decrease as pressure increases.

(B)are not affected by pressure change.

(C)are constant for all types of gases.

(D)are not affected by temperature changes.

(E)decrease as temperature increases.

38. Which solution contains the greatest mass of solute in 100 g of water? (carefulread all responses)

(A)A saturated solution of NaCl at 100 C

(B)A saturated solution of KCl at 50 C

(C)A saturated solution of NaNO3 at 25 C

(D)A saturated solution of KNO3 at 25 C

(E)A saturated solution of K2CrO4 at 50 C

39. Which of these compounds is least soluble in water? (hintuse solubility table!!)

(A)potassium chloride

(B)silver chloride

(C)magnesium chloride

(D)calcium chloride

(E)sodium nitrate

40. About how many grams of water would be needed to dissolve 20 g of potassium chlorate at 30 C?

(A)5 g(B)10 g(C)20 g(D)100 g

(E)200 g

41. At a constant temperature in a saturated aqueous salt solution in contact with undissolved salt

(A)addition of a common ion enables more salt to dissolve.

(B)the rate of dissolving exceeds that of crystallization.

(C)the rate of dissolving equals the rate of crystallization of the salt.

(D)the mass of salt in solution equals the mass of undissolved salt.

(E)all of the salt is found in the undissolved salt at the bottom of the container.

42. Two salts that are equally soluble at about 46 C are

(A)KBr and NaNO3

(B)KBr and K2Cr2O7

(C)NaCl and Ca(C2H3O2)22H2O

(D)K2Cr2O7 and Ca(C2H3O2)22H2O

43. Which curve represents the relationship between solubility and temperature of most solids, such as KNO3, in water?

(A)(C)

(B)(D)

44. Consider the graph:

Which compound is most soluble at 30 C?

(A)A(B)B(C)C(D)D

45. Which compound on the graph below has the least variation in solubility with a change in temperature from 0 to 80 C?

(A)KBr(C)K2Cr2O7

(B)NaCl(D)Ca(C2H3O2)2H2O

46. The curve that represents a substance that is slightly more soluble in hot than in cold water is,

(A)A(B)B(C)C(D)D

(E)E

47. At 10 C the substance that is most soluble is represented by curve

(A)A(B)B(C)C(D)D

(E)E

48. Which of these is a nonelectrolyte when dissolved in water?

(A)acetic acid(D)sodium chloride

(B)sulfuric acid(E)calcium hydroxide

(C)ethanol

49. Which is the best conductor of electricity?

(A)ether(D)sugar solution

(B)ethanol(E)carbon tetrachloride

(C)vinegar

50. Which solution contains the same total number of ions per liter as 1.0 M FeCl2?

(A)1.0 M AlCl3(C)0.5 M CuSO4

(B)2.0 M NaCl(D)1.5 M KBr

51. Which equation represents the dissolving of barium chloride, BaCl2, in water?

(A)BaCl2(s) Ba2+(aq) + Cl2(aq)

(B)BaCl2(s) Ba2+(aq) + 2Cl(aq)

(C)BaCl2(s) Ba(aq) + Cl2(aq)

(D)BaCl2(s) Ba(aq) + 2Cl(aq)

52. Which statement explains that a water solution of hydrogen chloride, HCl, is an excellent conductor, while pure liquid hydrogen chloride does not conduct electricity?

(A)Water is an electrolyte.

(B)Hydrogen chloride ionizes in water.

(C)Hydrogen chloride is a nonelectrolyte.

(D)Hydrogen chloride releases electrons in water.

53. What is the concentration of nitrate ion, NO3(aq), in a 0.2M Ba(NO3)2 solution?

Ba(NO3)2(s) Ba2+(aq) + 2NO3(aq)

(A)0.1 M(B)0.2 M(C)0.3 M(D)0.4 M

54. The equation for the dissociation of aluminum chloride is

AlCl3 Al 3+ + 3Cl

What is the concentration of chloride ion, Cl, in a 0.30 M AlCl3 solution?

(A)0.30 M(B)0.60 M(C)0.90 M(D)1.2 M

55. The phrase like dissolves like is frequently used in describing solutions. What is like?

(A)their densities (C)their heats of formation

(B)their molar masses(D)their molecular polarities

56. Which ion will form a precipitate when added to a 1 M hydroxide ion, OH(aq), solution?

(A)Cs+(aq)(C)Fe3+(aq)

(B)NH4+(aq) (D)SO42(aq)

57. How many moles of potassium hydroxide, KOH, are needed to prepare 2 L of a 2 M solution?

(A)1(B)2(C)3(D)4

58. How many moles of copper(II) ion, Cu2+, are present in 200 mL of a 0.250 M solution of CuSO4?

(A)0.0500(B)0.100(C)3.20(D)12.5

59. If 2.00 L of 0.600 M hydrochloric acid, HCl, and 3.00 L of 0.400 M hydrochloric acid are mixed, what is the concentration of the resulting solution?

(A)2.40 M(B)l.20 M(C)0.480 M(D)0.200 M

60. What is the molarity when 250 mL of a 3.0 M solution is diluted to one liter?

(A)0.75 M(B)1.2 M(C)3.0 M(D)7.5 M

61. What volume of concentrated sulfuric acid, 18.0 M H2SO4, is needed to make 2.00 L of a 1.00 M solution?

(A)18.0 mL(B)36.0 mL(C)98.0 mL(D)111 mL

62. How many grams of sucrose must be used to make 400 mL of 0.500 M sucrose solution?

Molar Masssucrose342. gmol1

(A)34.2 g(B)42.7 g(C)68.4 g(D)137 g

63. What is the molarity of 100 mL of solution containing 1.01 g of potassium nitrate, KNO3?

(A)1.00 M(C)0.100 M

(B)0.00100 M(D)10.0 M

64. What mass of solid calcium chloride, CaCl2, is dissolved in 1000 g of water to prepare a 0.400 m solution?

Atomic Molar MassesCa40.1 gmol1Cl35.5 gmol1

(A)4.40 g(B)14.8 g(C)44.4 g(D)55.5 g(E)111 g

65. Five different solutions were prepared by dissolving 0.1 mol of each of these materials in one liter of water. Which solution has the lowest freezing point?

(A)K2SO4(B)H2SO4(C)Na3PO4 (D)HCl(E)NaOH

66. One mole of the nonelectrolyte ethylene glycol is dissolved in 500 g of water. What is the freezing point of the solution?

Freezing Point Depression ConstantKf for water = 1.86 Cm1

(A)0.93 C(D)3.72 C

(B)1.86 C(E)5.58 C

(C)2.79 C

67. What is the boiling point of the solution formed by dissolving 0.25 mol of a nonvolatile, nonelectrolyte in 250 g of water at one atmosphere pressure?

Boiling Point Elevation ConstantKb for water = 0.52 Cm1

(A)100.00 C(D)100.78 C

(B)100.26 C(E)101.04 C

(C)100.52 C

68. What is the ideal freezing point of a 0.100 m NaCl solution?

Freezing Point Depression ConstantKf for water = 1.86 Cm1

(A)0.372 C (C)0.186 C

(B)0.186 C (D)0.372 C

UNIT 14 THERMOCHEMISTRY

69. The characteristic of a compound that is closely related to its heat of formation is its

(A)density.(D)solubility.

(B)stability. (E)boiling point.

(C)volatility.

70. In an exothermic reaction the temperature of a 100g water bath is raised 5 C. How many joules does the water absorb?

Specific heat capacity of water4.19 Jg1C1

(A)21 J(B)84 J(C)419 J(D)2090 J

71. How much heat is needed to vaporize one mole of H2O (liquid)?

H2(g) + 1/2O2(g) H2O(l) + 285.9 kJ

H2(g) + 1/2O2(g) H2O(g) + 242.0 kJ

(A)2.24 kJ(D)285.9 kJ

(B)43.9 kJ(E)527.9 kJ

(C)242.0 kJ

72. Note the equation:

2Fe(s) + 3/2O2(g) Fe2O3(s) H = 840 kJmol1 Fe2O3

If 0.100 mol of iron reacts, how much heat is liberated?

(A)42.0 kJ(D)420 kJ

(B)84.0 kJ(E)840 kJ

(C)210 kJ

73. Consider the equation:

2Al(s) + Fe2O3(s) 2Fe(s) + Al2O3(s) + 840 kJ

How many grams of aluminum react to produce 84 kJ of heat?

Atomic Molar MassAl27 gmol1

(A)2.7 g(B)5.4 g(C)9.0 g(D)27. g

(E)54. g

74. Consider the equations:

C(s) + O2(g) CO2(g)H = 393.7 kJmol1

CO(g) + 1/2O2(g) CO2(g)H = 283.1 kJmol1

From this information, calculate H of the equation

C(s) + 1/2O2(g) CO(g)

(A)110.6 kJmol1(C)393.7 kJmol1

(B)172.5 kJmol1(D)566.2 kJmol1

75. A table of heats (enthalpies) of formation is given.

CompoundHf (kJmol1)H2S(g)21O2(g)0H2O(l)285SO2(g)297What is the heat (enthalpy) of reaction, H, for this equation?

2H2S(g) + 3O2(g) 2H2O(l) + 2SO2(g)

(A)1122 kJ (C)+561 kJ

(B)603 kJ(D)+1122 kJ

76. According to their heats of formation, the most stable of these compounds is

(A)HIHf = 24.7 kJmol1

(B)H2SHf = +22.2 kJmol1

(C)HBrHf = +36.0 kJmol1

(D)HClHf = +92.1 kJmol1

(E)HFHf = +268.7 kJmol1

77. Which pair of changes insures that a chemical system undergoes a spontaneous reaction?

(A)a decrease in enthalpy and entropy

(B)an increase in enthalpy and entropy

(C)an increase in enthalpy with entropy constant

(D)an increase in enthalpy and a decrease in entropy

(E)a decrease in enthalpy and an increase in entropy

78. In which system does randomness decrease?

(A)ice melting

(B)solid iodine subliming

(C)methane gas crystallizing

(D)salt dissolving in water

(E)liquid alcohol evaporating

79. Which forward reaction shows an increase in entropy (disorder)?

(A)CaCO3(s) CaO(s) + CO2(g)

(B)2H2(g) + O2(g) 2H2O(l)

(C)H2(g) + CuO(s) H2O(l) + Cu(s)

(D)HCl(g) + NH3(g) NH4Cl(s)

80. In which state does a sample of benzene have the lowest entropy?

(A)crystalline benzene at 5.5 C

(B)liquid benzene at 5.5 C

(C)benzene vapor at 5.5 C

(D)a mixture of benzene vapor and air at 5.5 C

UNIT 15 REACTION KINETICS

81. This potential energy diagram shows that the reaction A + B C is

(A)slow.(D)endothermic.

(B)rapid.(E)at equilibrium.

(C)exothermic.

82. For the reaction

A + B C + D

the figure is the potentialenergy diagram

What interval represents the net energy change for this reaction?

(A)1(B)2(C)3(D)4

83. Which arrow on this diagram represents the heat of reaction?

(A)A(B)B(C)C(D)D

84. A particular exothermic reaction occurs spontaneously. Which diagram fits this reaction?

(A)(C)

(B)(D)

85. What is the heat of reaction, H, for the reaction A B?

(A)0 kJmol1(C)40 kJmol1

(B)20 kJmol1 (D)80 kJmol1

86. Which best explains how catalysts increase the rate of a chemical reaction?

(A)They reduce the amount of product.

(B)They increase the amount of product.

(C)They reduce the amount of reactants.

(D)They raise the temperature of the reaction.

(E)They reduce the activation energy of the reaction.

87. Consider the energy diagram for the reaction A B

Which diagram represents reaction A B using a catalyst?

(A)(C)

(B) (D)

88. In the reaction mechanism for the decomposition of formic acid, HCOOH,

HCOOH(l) + H+(aq) HCOOH2 +(aq)

HCOOH2 +(aq) HCO+(aq) + H2O(l)

HCO+(aq) CO(g) + H+(aq)

which species acts as a catalyst?

(A)H+(aq)(C)H2O(l)

(B)CO(l)(D)HCOOH2+(aq)

89. On this kinetic energy distribution diagram, in which region can all collisions result in a chemical reaction?

(A)A only(C)A, B, and C

(B)C only(D)D only

90. Why does flour burn slowly when in a pile, but rapidly when blown into the air?

(A)Dispersing the particles allows more energy to be released.

(B)Dispersed particles have a greater surface area in contact with the air.

(C)The H of the dispersed particles is greater.

(D)Air circulating around the particles distributes heat more evenly.

91. Which is the ratedetermining step in this hypothetical reaction mechanism?

Species Being FormedRate of its FormationB0.0020 mol/hour per mole of AC0.030 mol/hour per mole of BD0.011 mol/hour per mole of CE0.42 mol/hour per mole of D

(A)step 1(B)step 2(C)step 3(D)step 4

92. A reaction mechanism has several steps. The rate of the overall reaction is equal to

(A)the rate of the fastest step.

(B)the rate of the slowest step.

(C)the average of the rates of the steps.

(D)the difference between the rate of the fastest step and the rate of the slowest step.

93. Generally an increase of ten degrees Celsius doubles the rate of reaction between gases. What is the explanation for this increase in reaction rate?

(A)The pressure is doubled.

(B)The concentration of the reactants is doubled.

(C)The average kinetic energy of the molecules is doubled.

(D)The number of intermolecuiar collisions per unit of time is doubled.

(E)The number of particles with an energy above a minimum activation energy is doubled.

94. The reaction A + B C + D follows the energy path shown below. What is the activation energy for the reverse reaction?

(A)60 kJmol1(D)20 kJmol1

(B)50 kJmol1(E)10 kJmol1

(C)30 kJmol1

95. Consider the diagram for the reaction

A(g) + B(g) C(g) + D(g)

What is the activation energy for this reaction?

(A)+20 kJmol1(C)+60 kJmol1

(B)+40 kJmol1(D)60 kJmol1

96. Consider this reaction at 500 C:

4HBr(g) + O2(g) 2H2O(g) + 2Br2(g)

What is the activation energy for the reverse reaction?

(A)118 kJ(B)276 kJ(C)158 kJ(D)434 kJ

UNIT 16 EQUILIBRIUM

97.

UNIT 17 ACID/BASE CHEMISTRY

UNIT 18 ELECTROCHEMISTRY

Answer Sheet 2nd semester review:

UNIT 5GAS LAWS

1. D6. B11. E16. A21. C26. C31. A2. E7. B12. E17. D22. B27. C32. A3. C8. C13. B18. D23. C28. D33. E4. A9. C14. A19. B24. A29. A34. B5. A10. A15. C20. A25. D30. C

UNIT 6 SOLUTIONS/CONDENSED STATE OF MATTER

35. A41. C46. C51. B56. C61. D66. D36. B42. D47. C52. B57. D62. C67. C37. E43. C48. C53. D58. A63. C68. D38. C44. B49. C54. C59. C64. C39. B45. B50. D55. D60. A65. C40. E

UNIT 14 THERMOCHEMISTRY

69. B71. B73. B75. A77. E79. A70. D72. A74. A76. E78. C80. A

UNIT 15 REACTION KINETICS

81. C84. B87. C89. D91. A93. E95. C82. D85. C88. A90. B92. B94. D96. D83. B86. E