Chapter 12 – Physical Properties of Solutions
40. The solubility of nitrogen gas at 25C and a nitrogen pressure of 522 mmHg is 4.7 10–4
mol/L. What is the value of the Henry’s Law constant in mol/L·atm?
41. The solubility of oxygen in lakes high in the Rocky Mountains is affected by the altitude.
If the solubility of O2 from the air is 2.67 10–4 M at sea level and 25C, what is the
solubility of O2 at an elevation of 12,000 ft where the atmospheric pressure is 0.657 atm?
Assume the temperature is 25C, and that the mole fraction of O2 in air is 0.209 at both
12,000 ft and at sea level.
Chapter 12 – Physical Properties of Solutions
42. At 10C one volume of water dissolves 3.10 volumes of chlorine gas at 1.00 atm pressure.
What is the Henry’s Law constant in mol/L·atm?
43. According to Raoult’s law, which statement is false?
Chapter 12 – Physical Properties of Solutions
44. Consider a solution made from a nonvolatile solute and a volatile solvent. Which
45. The vapor pressure of water at 45.0 C is 71.93 mmHg. What is the vapor pressure of
water over a solution prepared from 75.0 g of citric acid (C6H8O7) in 0.420 kg of water at this
temperature?
Chapter 12 – Physical Properties of Solutions
46. The vapor pressure of water at 20C is 17.5 mmHg. What is the vapor pressure of water
over a solution prepared from 2.00 102 g of sucrose (C12H22O11) and 3.50 102 g water?
47. A solution is 40.0% by mass benzene (C6H6) in carbon tetrachloride (CCl4) at 20C. The
vapor pressure of pure benzene and pure carbon tetrachloride at this temperature is 74.61
mmHg and 91.32 mmHg, respectively. Calculate the vapor pressure of the solution at 20C:
Chapter 12 – Physical Properties of Solutions
48. A solution is 35.0% by mass carbon tetrachloride (CCl4) in benzene (C6H6) at 20C. The
vapor pressure of pure benzene and pure carbon tetrachloride at this temperature is 74.61
mmHg and 91.32 mmHg, respectively. Calculate the vapor pressure of the solution at 20C:
49. A solution of chloroform, CHCl3, and acetone, (CH3)2CO, exhibits a negative deviation
from Raoult’s law. This result implies that
Chapter 12 – Physical Properties of Solutions
50. What is the freezing point of a solution that contains 10.0 g of glucose (C6H12O6) in 100.g
of H2O? Kf for water is 1.86C/m.
51. Which of the following aqueous solutions has the highest boiling point (assume 100%
dissociation for all soluble ionic compounds)?
Chapter 12 – Physical Properties of Solutions
52. Which of the following aqueous solutions has the highest osmotic pressure at 25C
(assume 100% dissociation for all soluble ionic compounds)?
53. During osmosis
Chapter 12 – Physical Properties of Solutions
54. Calculate the freezing point of a solution made from 22.0 g of octane (C8H18) dissolved in
148.0 g of benzene. Benzene freezes at 5.50C and its Kf value is 5.12C/m.
55. What is the freezing point of a solution prepared from 50.0 g ethylene glycol (C2H6O2)
and 85.0 g H2O? Kf of water is 1.86C/m.
Chapter 12 – Physical Properties of Solutions
56. A solution that contains 55.0 g of ascorbic acid (Vitamin C) in 250. g of water freezes at –
2.34C. Calculate the molar mass (in units of g/mol) of the solute. Kf of water is 1.86C/m.
57. What is the molar mass of toluene if 0.85 g of toluene depresses the freezing point of 100.
g of benzene by 0.47C? Kf of benzene is 5.12C/m.
Chapter 12 – Physical Properties of Solutions
58. When 24.0 g of glucose (a nonelectrolyte) is dissolved in 500. g of water, the solution has
a freezing point of –0.47C. What is the molar mass of glucose? Kf of water is 1.86C/m.
59. What is the osmotic pressure of a solution that contains 13.7 g of propyl alcohol
(C3H7OH) dissolved in enough water to make 500. mL of solution at 27C?
Chapter 12 – Physical Properties of Solutions
60. What is the freezing point of an aqueous solution of a nonvolatile solute that has a boiling
point of 102.5C? For water Kf = 1.86C/m and Kb = 0.52C/m.
61. What is the boiling point of a solution of 12.0 g of urea (CH4N2O) in 165.0 g of water?
(Kb (H2O) = 0.52 C/m)
Chapter 12 – Physical Properties of Solutions
62. What is the boiling point of a solution of 11.0 g of lactose (C12H22O11) in 145.0g of water?
(Kb (H2O) = 0.52 C/m)
63. Pure benzene, C6H6, freezes at 5.5C and boils at 80.1C. What is the boiling point of a
solution consisting of cyclohexane (C6H12) dissolved in benzene if the freezing point of this
solution is 0.0C? (For benzene, Kf = 5.12 C/m, Kb = 2.53 C/m; for cyclohexane, Kf = 20.0
C/m, Kb = 2.79C/m)
Chapter 12 – Physical Properties of Solutions
64. When 12.1 g of the sugar sucrose (a nonelectrolyte) is dissolved in exactly 800.0 g of
water, the solution has a freezing point of –0.082C. What is the molar mass of sucrose? Kf of
water is 1.86C/m.
65.
What is the osmotic pressure of a 0.25 M solution of sucrose at 37C? (R = 0.0821 L·atm/K·mol)
Chapter 12 – Physical Properties of Solutions
66.
How many grams of sucrose (C12H22O11, 342.3 g/mol) would be needed to make 2.5 L of a solution with an osmotic pressure
of 14 atm at 25C? (R = 0.0821 L·atm/K·mol)
67. What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic
pressure of 10.50 atm at 25C? Kb of water is 0.52C/m. Assume the density of the solution is
the same as that of pure water.
Chapter 12 – Physical Properties of Solutions
68. 0.102 g of an unknown compound dissolved in 100. mL of water has an osmotic pressure
of 28.1 mmHg at 20C. Calculate the molar mass of the compound.
69. An aqueous dextrose solution having a density of 1.04 g/cm3 freezes at –1.15C. Find the
osmotic pressure of this solution at 25C. Kf of water is 1.86 C/m; molecular mass of
dextrose = 180.16 g/mol.
Chapter 12 – Physical Properties of Solutions
70. An aqueous fructose solution having a density of 1.049 g/cm3 is found to have an osmotic
pressure of 17.0 atm at 25C. Find the temperature at which this solution freezes. [Given: for
water Kf = 1.86 C/m; molecular mass of fructose = 180.16 g/mol]
71. Calculate the approximate freezing point of a solution made from 21.0 g NaCl and 1.00
102 g of H2O. [Kf of water is 1.86C/m.]
Chapter 12 – Physical Properties of Solutions
72. What is the osmotic pressure of a solution prepared from 13.7 g of the electrolyte HCl and
enough water to make 0.500 L of solution at 18C?
73. Arrange the following aqueous solutions in order of increasing boiling points: 0.300m
C6H12O6, 0.110m K2CO3, and 0.050m Al(ClO4)3.
Chapter 12 – Physical Properties of Solutions
74. Arrange the following aqueous solutions in order of increasing boiling points: 0.050m
Mg(NO3)2; 0.100m ethanol; 0.090m NaCl.
75. Assuming 100% dissociation, which of the following compounds is listed incorrectly with
its van’t Hoff factor i?
Chapter 12 – Physical Properties of Solutions
76. Assuming 100% dissociation, which of the following compounds is listed correctly with
its van’t Hoff factor i?
77. The osmotic pressure of a 0.010 M MgSO4 solution at 25C is 0.318 atm. Calculate i, the
van’t Hoff factor, for this MgSO4 solution.
Chapter 12 – Physical Properties of Solutions
78. Calculate the boiling point of a 4.5 m solution of Na2SO4 in water (assume 100%
dissociation, Kb (H2O) = 0.52 C/m).
79. If 14.2 g of Al(NO3)3 is dissolved in 655g of water, what is the boiling point of the
solution (assume 100% dissociation, Kb (H2O) = 0.52 C/m)?