Tb chapter12 cccccccccccccccccccccc

Chapter 12 - Solutions
1. Which of the following concerning solutions is/are correct?
1. The solvent in a mixture of gases is generally considered to be the substance
in greater amount.
2. The solid dissolved in a solution is known as the solute.
3. Solid solutions are called alloys.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1, 2, and 3
ANS: E PTS: 1 DIF: easy REF: 12.1
OBJ: Types of Solutions TOP: solutions | solution formation
2. Which of the following concerning solutions is/are correct?
1. For a solution to form, the solvent and solute must be miscible.
2. A solution may be homogeneous or heterogeneous.
3. A colloid is a type of solution.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1, 2, and 3
ANS: A PTS: 1 DIF: easy REF: 12.1
OBJ: Types of Solutions TOP: solutions | solution formation
3. Suppose a small amount of a solid is added to water and, after a short time, all the solid has
dissolved. Which of the following statements is most likely to be true?
A) The solution is supersaturated with solute.
B) The solution is saturated with solute.
C) The solution is unsaturated with solute.
D) The solution is either unsaturated or supersaturated with solute.
E) The solution is either saturated or supersaturated with solute.
ANS: C PTS: 1 DIF: easy REF: 12.2
OBJ: List the conditions that must be present to have a saturated solution, to have an
unsaturated solution, and to have a supersaturated solution.
TOP: solutions | solution formation KEY: solubility | saturated solution
MSC: general chemistry
Test Bank General Chemistry, 10th
edition 1

4. Which of the following concerning solubility and the solution process is/are correct?
1. In a saturated solution of a substance, a solution of the substance is in
equilibrium with the pure substance.
2. Dissolution of a solute stops once saturation of a solvent is achieved.
3. Solubility depends in part on the strength of solute-solute and solute-solvent
Van der Waals forces.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 3
E) 1, 2, and 3
ANS: D PTS: 1 DIF: easy REF: 12.2
TOP: solutions | solution formation
5. Which of the following concerning solubility and the solution process is/are correct?
1. Both hydration energies and lattice energies depend on the magnitude of the
ion charges and the size of the ions.
2. An initially nonhomogeneous mixture of two miscible liquids, given enough
time, will eventually form a solution as a result of random molecular motions.
3. The dissolution of ionic compounds in water depends only on the hydration
energy of the ions.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1, 2, and 3
6. Which of the following sets of conditions favors maximum solubility of solute in solvent?
A) The intermolecular forces between solute and solvent molecules are much weaker
than the intermolecular forces between solute molecules, but much stronger than
the intermolecular forces between solvent molecules.
B) The intermolecular forces between solute and solvent molecules are much stronger
than the intermolecular forces between solute molecules or the intermolecular
forces between solvent molecules.
C) The intermolecular forces between solute and solvent molecules are much stronger
than the intermolecular forces between solvent molecules, but much weaker than
the intermolecular forces between solute molecules.
edition 2

D) The intermolecular forces between solute and solvent molecules are much stronger
than the intermolecular forces between solute molecules, but much weaker than the
intermolecular forces between solvent molecules.
E) The intermolecular forces between solute and solvent molecules are much weaker
than the intermolecular forces between solute molecules or the intermolecular
forces between solvent molecules.
ANS: B PTS: 1 DIF: easy REF: 12.2
OBJ: Describe the factors that make one substance soluble in another.
TOP: solutions | solution formation KEY: solubility MSC: general chemistry
7. In general, which of the following type(s) of solid(s) would exhibit the greatest solubility in
a nonpolar solvent?
A) network covalent
B) nonpolar molecular
C) ionic
D) metallic
E) polar molecular
OBJ: Describe the factors that make one substance soluble in another.
8. Which of the following gases is least soluble in water?
A) CO2
B) SO3
C) NH3
D) N2
E) HCl
OBJ: Determine when a molecular solution will form when substances are mixed.
TOP: solutions | solution formation KEY: solubility | molecular solution
9. Which of the following pure liquids is the best solvent for sodium fluoride?
A) CCl4(l)
B) C2Cl6(l)
C) HCl(l)
D) BCl3(l)
E) PCl5(l)
TOP: solutions | solution formation KEY: solubility | ionic solution
edition 3

10. Which of the following pure liquids is the best solvent for carbon disulfide?
A) C6H6(l)
B) NH3(l)
C) CH3OH(l)
D) H2O(l)
E) HBr(l)
11. Which of the following compounds is least soluble in water?
A) CH3CH2CH2NH2
B) CH3CH2CH2F
C) CH3CH(OH)CH3
D) CH3CH2COOH
E) CH3CH2NHCH3
12. The solubility of 1-hexanol in water is 0.60 g per 100 g of water at 25°C. What is the
maximum amount of 1-hexanol that will dissolve in 5.3 g of water at 25°C?
A) 0.032 g
B) 0.11 g
C) 0.60 g
D) 3.2 g
E) 0.0011 g
13. Which of the following sets of conditions favors maximum solubility of an ionic solute in
water?
A) The enthalpy of hydration of the cation should be equal to the enthalpy of
hydration of the anion, regardless of the magnitude of the lattice energy.
B) The magnitude of the lattice energy should be small, and the enthalpy of hydration
of the ions should be large.
C) The magnitude of the lattice energy should be small, and the enthalpy of hydration
of the ions should be small.
D) The magnitude of the lattice energy should be large, and the enthalpy of hydration
of the ions should be small.
E) The magnitude of the lattice energy should be large, and the enthalpy of hydration
of the ions should be large.
edition 4

OBJ: Learn what conditions must be met in order to create an ionic solution.
14. Which of the following favor(s) the solubility of an ionic solid in a liquid solvent?
A) a small magnitude of the lattice energy of the solute
B) a large magnitude of the solvation energy of the ions
C) a large polarity of the solvent
D) all of the above
E) none of the above
15. Which of the following statements best describes what happens when a small amount of
solid rubidium bromide is dissolved in water?
A) The heat from the warm water melts the solid, making it a liquid.
B) Nothing happens, because rubidium bromide is insoluble in water.
C) The solid RbBr breaks apart into separate Rb and Br atoms by interacting with the
water molecules.
D) The water molecules surround each ion in the solid RbBr, separating the Rb ions
from the Br ions.
E) The solid undergoes a chemical change by reacting with the water.
16. Which of the following correctly states the relationship between the solubility of a substance
in water and temperature?
A) The solubility of a substance in water increases as the temperature rises, especially
for gases.
B) The solubility of a substance in water decreases as the temperature lowers,
especially for gases.
C) The relationship between the solubility of a substance in water and temperature
cannot be accurately predicted, especially for ionic solids.
D) The solubility of a substance in water decreases as the temperature rises, especially
for ionic solids.
E) Two of these are correct.
OBJ: State the general trends of the solubility of gases and solids with temperature.
KEY: effect of temperature and pressure on solubility | temperature change
edition 5

17. Which of the following concerning the effects of temperature and pressure on solubility
is/are correct?
1. All gases become more soluble in a liquid at a fixed pressure when the
temperature of the liquid is increased.
2. The dissolution of an ionic compound in water may be exothermic or
endothermic, depending on the initial temperature of the solution.
3. The solubility of a liquid in water generally is significantly effected by
pressure changes of the system.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) none
18. Consider the following gas-aqueous liquid equilibrium for a closed system at a constant
temperature.
O2(g) O2(aq)
What is the effect on the equilibrium composition of the liquid when the partial pressure of
O2 gas above the liquid is increased?
A) The amount of O2 dissolved in the liquid increases.
B) The amount of O2 dissolved in the liquid decreases.
C) The amount of O2 dissolved in the liquid does not change.
D) Not enough information is provided to answer the question.
E) Either A or B.
19. Consider the following gas-liquid equilibrium for an aqueous system at a constant partial
pressure of N2.
N2(g) N2(aq)
What is the effect on the equilibrium composition of the liquid when the temperature of the
liquid is increased?
edition 6

A) The amount of N2 dissolved in the liquid increases.
B) The amount of N2 dissolved in the liquid decreases.
C) The amount of N2 dissolved in the liquid does not change.
D) Not enough information is provided to answer the question.
E) Either A or B could occur.
20. Which of the following affect(s) the solubility of gases in solvents?
1. the nature of the gas
2. the nature of the solvent
3. the temperature of the solvent
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1, 2, and 3
KEY: effect of temperature and pressure on solubility | temperature change
21. How does the solubility of a gas in a solvent depend on pressure and temperature?
A) Increasing the partial pressure of the gas while increasing the temperature
increases the solubility of the gas.
B) Decreasing the partial pressure of the gas while decreasing the temperature
C) Increasing the partial pressure of the gas while decreasing the temperature
D) Decreasing the partial pressure of the gas while increasing the temperature
E) Gas solubility is unaffected by pressure or temperature.
OBJ: Explain how the solubility of a gas changes with temperature.
KEY: effect of temperature and pressure on solubility MSC: general chemistry
edition 7

22. Which of the following is a correct statement of Henry's law?
A) The concentration of a gas in solution is directly proportional to the mole fraction
of solvent.
B) The concentration of a gas in solution is inversely proportional to temperature.
C) The concentration of a gas in solution is independent of pressure.
D) The concentration of a gas in a solution is inversely proportional to pressure.
E) none of these
OBJ: Apply Henry’s law. (Example 12.1)
KEY: effect of temperature and pressure on solubility | Henry's law
23. The solubility of a gas in a liquid can always be increased by
A) decreasing the pressure of the gas above the solvent.
B) increasing the pressure of the gas above the solvent.
C) increasing the temperature of the solvent.
D) decreasing the polarity of the solvent.
E) decreasing the temperature of the gas above the solvent.
KEY: effect of temperature and pressure on solubility | pressure change
24. At a particular temperature the solubility of O2 in water is 0.590 g/L at an oxygen pressure
of around 14.7 atm. What is the Henry's law constant for O2 (in units of L · atm/mol)?
A) 4.01 × 10-2
B) 7.97 × 102
C) 2.71 × 10-1
D) 1.25 × 10-3
E) None of the above are within 5% of the correct answer.
ANS: B PTS: 1 DIF: moderate REF: 12.3
KEY: effect of temperature and pressure on solubility | Henry's law
edition 8

25. According to the National Institute of Standards webbook, the Henry’s Law constant for N2
gas is 0.00060 mol/kg⋅bar at 25°C What is the Henry's law constant in units of mol/kg⋅atm?
(1 bar = 0.9869 atm; 1 atm = 760 mmHg)
A) 6.1 × 10
−4
mol/kg⋅atm
B) 8.0 × 10
−7
mol/kg⋅atm
C) 4.6 × 10
−1
mol/kg⋅atm
D) 1.6 × 10
3
mol/kg⋅atm
E) 1.3 × 10
6
mol/kg⋅atm
26. Henry’s Law constant is 0.00060 mol/kg⋅bar and 0.0013 mol/kg⋅bar for N2 and O2
respectively at 25°C. What pressure of O2 is required to achieve the same solubility as 0.616
bar of N2?
A) 0.28 bar
B) 1.3 bar
C) 4.8 × 10
−7
bar
D) 1.3 × 10
−6
bar
E) 3.5 bar
27. If the solubility of O2 at 0.360 bar and 25°C is 15.0 g/100 g H2O, what is the solubility of O2
at a pressure of 1.72 bar and 25°C?
A) 71.7 g/100 g H2O
B) 24.2 g/100 g H2O
C) 0.319 g/100 g H2O
D) 0.0140 g/100 g H2O
E) 3.14 g/100 g H2O
ANS: A PTS: 1 DIF: moderate REF: 12.3
28. Which of the following is not a colligative property?
A) boiling-point elevation
B) osmotic pressure
C) gas solubility
D) freezing-point lowering
E) vapor-pressure lowering
edition 9

OBJ: Define colligative property. TOP: solutions | colligative properties
29. As the number of solute particles in a given volume of solution increases,
A) the boiling point will increase and the vapor pressure will increase.
B) the freezing point will decrease and the vapor pressure will decrease.
C) the freezing point will increase and the vapor pressure will increase.
D) the boiling point will decrease and the vapor pressure will decrease.
E) the osmotic pressure will decrease and the lattice energy will increase.
OBJ: Define colligative property. TOP: solutions | colligative properties
30. The molarity of a solution is defined as the
A) moles of solute per liter of solvent.
B) grams of solute per kilogram of solvent.
C) grams of solute per liter of solution.
D) moles of solute per liter of solution.
E) moles of solute per kilogram of solvent.
OBJ: Define molarity. TOP: solutions | colligative properties
KEY: expressing concentration MSC: general chemistry
31. The molarity of a solution is defined as the
A) moles of solute per liter of solvent.
B) moles of solute per kilogram of solution.
C) moles of solute per mole of solution.
D) moles of solute per kilogram of solvent.
E) moles of solute per liter of solution.
OBJ: Define molarity. TOP: solutions | colligative properties
KEY: expressing concentration MSC: general chemistry
32. The molality of a solution is defined as
A) moles of solute per liter of solution.
B) the gram molecular weight of solute per kilogram of solvent.
C) moles of solute per kilogram of solvent.
D) grams of solute per liter of solution.
E) moles of solute per kilogram of solution.
OBJ: Define molality. TOP: solutions | colligative properties
KEY: expressing concentration | molality MSC: general chemistry
edition 10

33. Which of the following concerning the topic of concentration is/are correct?
1. A concentrated solution of hydrochloric acid has a molarity of 12 M. This
means that 12 moles of HCl are dissolved in 1.0 L of water.
2. The molality of a solution is unaffected by changes in temperature, even
though the total volume of the solution may change significantly.
3. When calculating a mass percent, the “mass of solution” is equal to the sum of
the masses of all solution components.
A) 1 only
B) 2 only
C) 3 only
D) 2 and 3
E) 1, 2, and 3
OBJ: Define all concentration units. TOP: solutions | colligative properties
34. Which of the following concerning the topic of concentration is/are correct?
1. A 5.0 molal HCl solution consists of 5.5 moles HCl dissolved in 1.0 kg of
solution.
2. The mass percent and mole percent of a particular component in a solution are
identical.
3. The mole fraction of a component in a solution may never be greater than 1.
A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) none of the above
OBJ: Define all concentration units. TOP: solutions | colligative properties
35. What mass of an aqueous 22.9% sodium chloride solution contains 99.5 g of water?
A) 129 g
B) 29.6 g
C) 0.500 g
D) 22.8 g
E) 99.5 g
OBJ: Calculate mass percentage of solute. (Example 12.2)
TOP: solutions | colligative properties
edition 11

36. What is the mass of H2SO4 in a 49.5-cm3
sample of concentrated sulfuric acid that has a
density of 1.84 g/cm3
and consists of 98.3% H2SO4?
A) 48.7 g
B) 89.5 g
C) 3.65 g
D) 1.81 g
E) 26.4 g
KEY: expressing concentration | mass percentage of solute MSC: general chemistry
37. A concentrated sulfuric acid solution is 65.0% H2SO4 by mass and has a density of 1.55
g/mL at 20°C. What is the mass of 3.00 L of the concentrated sulfuric acid solution?
A) 1.95 kg
B) 3.00 kg
C) 7.15 kg
D) 1.26 kg
E) 4.65 kg
38. A concentrated potassium hydroxide solution is 45.0% KOH by mass and has a density of
1.44 g/mL at 25°C. What is the mass of KOH per L of solution?
A) 648 g KOH/L soln
B) 0.00144 g KOH/L soln
C) 313 g KOH/L soln
D) 0.320 g KOH/L soln
E) 3.13 g KOH/L soln
39. A concentrated phosphoric acid solution is 85.5% H3PO4 by mass and has a density of 1.69
g/mL at 25°C. What is the molarity of H3PO4?
A) 14.7 M
B) 0.166 M
C) 5.16 M
D) 19.4 M
E) 0.0516 M
edition 12

40. A concentrated perchloric acid solution has a density of 1.67 g/mL at 25°C and is 11.7 M.
What is the percent by mass of HClO4 in the solution?
A) 70.4% HClO4 by mass
B) 0.702% HClO4 by mass
C) 1.42% HClO4 by mass
D) 0.699% HClO4 by mass
E) 60.2% HClO4 by mass
41. What is the mass percent of an aqueous sodium hydroxide solution in which the mole
fraction of NaOH is 0.231? The density of the solution is 1.4339 g/mL.
A) 40.0%
B) 6.21%
C) 68.9%
D) 33.1%
E) 6.44%
ANS: A PTS: 1 DIF: difficult REF: 12.4
KEY: expressing concentration | conversion of concentration units
42. What is the mass percent of an aqueous sodium hydroxide solution in which the molarity of
NaOH is 4.37 M? The density of the solution is 1.1655 g/mL.
A) 0.267%
B) 15.0%
C) 5.09%
D) 1.53%
E) 68.9%
ANS: B PTS: 1 DIF: difficult REF: 12.4
43. What is the mass percent of an aqueous sodium hydroxide solution in which the molality of
NaOH is 25.0 m? The density of the solution is 1.5290 g/mL.
A) 0.0612%
B) 68.9%
C) 1.76%
D) 50.0%
E) 0.654%
edition 13

ANS: D PTS: 1 DIF: difficult REF: 12.4
44. The mass of a 12.0% (by mass) solution is 8.82 g. The density of the solution is
1.120 g/mL. What is the mass of the water in this solution?
A) 7.76 g
B) 10 g
C) 1.19 g
D) 0.00774 g
E) 8.69 g
45. The volume of a 14.4% (by mass) solution is 67.0 mL. The density of the solution is
1.072 g/mL. What is the mass of the solution?
A) 71.8 g
B) 62.5 g
C) 1030 g
D) 103 g
E) 10.3 g
46. The volume of a 15.8% (by mass) solution is 146.4 mL. The density of the solution is
1.084 g/mL. What is the mass of solute in this solution?
A) 159 g
B) 25.1 g
C) 1004 g
D) 21.3 g
E) 134 g
edition 14

47. What is the molarity of a 20.0% by mass hydrochloric acid solution? The density of the
solution is 1.0980 g/mL.
A) 6.86 M
B) 0.200 M
C) 5.68 M
D) 6.02 M
E) 0.0220 M
ANS: D PTS: 1 DIF: moderate REF: 12.4
48. What mass of a 26.0% by mass glucose, C6H12O6, solution contains 42.0 g of glucose?
A) 46.8 g
B) 162 g
C) 10.9 g
D) 60.7 g
E) 42.0 g
49. What is the percent Na2CO3 by mass in a 1.54 molal aqueous solution?
A) 0.132%
B) 14.0%
C) 99.4%
D) 16.3%
E) 15.4%
50. What mass of a solution labeled 6.3% sucrose (C12H22O11, 342 g/mol) by mass contains
15.0 g of sucrose?
A) 3.4 g
B) 39 g
C) 240 g
D) 0.28 g
E) 95 g
edition 15

51. A 12.0% sucrose solution by mass has a density of 1.05 g/cm3
. What mass of sucrose is
present in a 30.0-mL sample of this solution?
A) 3.78 g
B) 3.43 g
C) 0.126 g
D) 263 g
E) 3.60 g
52. How many moles of urea (60. g/mol) must be dissolved in 77.6 g of water to give a 3.5 m
solution?
A) 2.1 × 102
mol
B) 3.5 mol
C) 0.0035 mol
D) 0.27 mol
E) 7.7 × 102
mol
OBJ: Calculate the molality of solute. (Example 12.3)
TOP: solutions | colligative properties KEY: expressing concentration | molality
53. If 12.7 g of naphthalene, C10H8, is dissolved in 104.6 g of chloroform, CHCl3, what is the
molality of the solution?
A) 0.0992 m
B) 14.5 m
C) 0.949 m
D) 0.108 m
E) 0.113 m
54. What is the molality of a solution prepared by dissolving 0.244 mol of chloroform, CHCl3,
in 456 g of toluene, C6H5CH3?
A) 0.0642 m
B) 0.0469 m
C) 0.535 m
D) 0.0492 m
E) 1.113 m
edition 16

edition 17

55. What is the molality of a solution prepared by dissolving 2.57 g of urea, NH2CONH2, in
57.6 g of water?
A) 0.0427 m
B) 0.0446 m
C) 0.0132 m
D) 0.743 m
E) 0.000711 m
56. A 3.140 molal solution of NaCl is prepared. How many grams of NaCl are present in a
sample containing 2.191 kg of water?
A) 243.9 g
B) 402.1 g
C) 117.7 g
D) 688.0 g
E) none of these
57. What is the molality of a solution that contains 77.7 g of 1,4-dichlorobenzene (C6H4Cl2) in
445 mL of carbon tetrachloride (CCl4)? The density of CCl4 is 1.60 g/mL.
A) 0.183 m
B) 0.743 m
C) 0.175 m
D) 0.109 m
E) 1.90 m
58. What is the molality of ethanol, C2H5OH, in an aqueous solution that is 51.0% ethanol by
mass?
A) 1.04 m
B) 0.0226 m
C) 22.6 m
D) 0.719 m
E) 53.4 m
ANS: C PTS: 1 DIF: moderate REF: 12.4
TOP: solutions | colligative properties KEY: expressing concentration |
conversion of concentration units MSC: general chemistry
edition 18

59. A concentrated potassium hydroxide solution is 45.0% KOH by mass and has a density of
1.44 g/mL at 25°C. The remainder of material is solvent. What is the molality of KOH in
the solution?
A) 14.6 m
B) 8.02 m
C) 5.53 m
D) 686 m
E) 1.02 m
60. What is the molality of a 20.0% by mass hydrochloric acid solution? The density of the
solution is 1.0980 g/mL.
A) 0.0220 m
B) 6.86 m
C) 0.200 m
D) 5.68 m
E) 6.02 m
61. What is the molality of a solution that contains 8.16 g of glucose, C6H12O6, in 252.5 g of
water?
A) 0.180 m
B) 0.0453 m
C) 0.00322 m
D) 0.0114 m
E) 0.0323 m
TOP: phases | colligative properties KEY: expressing concentration
62. For a solution containing only one solute dissolved in a solvent, we can calculate the mole
fraction of the solvent directly, given only
A) the molar mass of the solute.
B) the density of the solution.
C) the molar mass of the solvent.
D) the mole fraction of the solute.
E) the molarity of the solution.
edition 19

OBJ: Define mole fraction. TOP: solutions | colligative properties
KEY: expressing concentration | mole fraction MSC: general chemistry
63. What is the mole fraction of urea, CH4N2O, in an aqueous solution that is 36% urea by
mass?
A) 0.14
B) 0.86
C) 0.36
D) 0.55
E) 0.65
OBJ: Calculate the mole fraction of components. (Example 12.4)
TOP: solutions | colligative properties KEY: expressing concentration | mole fraction
64. What is the mole fraction of urea, CO(NH2)2,in a solution prepared by dissolving 6.8 g of
urea in 33.5 g of methanol, CH3OH?
A) 0.83
B) 0.17
C) 0.098
D) 0.90
E) 0.28
65. What is the mole fraction of toluene in a solution of 3.4 mol of benzene and 5.2 mol of
toluene?
A) 0.64
B) 0.54
C) 0.60
D) 0.24
E) 0.40
66. What is the mole fraction of water in a solution that contains 6.8 mol of ethanol (C2H5OH)
and 1.2 mol of water?
A) 0.15
B) 0.07
C) 0.57
D) 0.18
E) 0.85
edition 20

67. What is the mole fraction of water in a water–ethanol solution that is 46.0% water by mass?
(Ethanol is C2H5OH.)
A) 0.28
B) 0.31
C) 0.25
D) 0.69
E) 0.54
68. What is the mole fraction of urea in a solution that contains 2.1 mol of urea and 4.4 mol of
water?
A) 0.77
B) 0.32
C) 0.42
D) 0.52
E) 0.68
69. Which way of expressing concentration is used to relate the vapor pressure of a solution to
the amount of nonvolatile solute dissolved in the solution?
A) mole fraction
B) molarity
C) osmotic pressure
D) mass percent
E) molality
OBJ: State Raoult’s law. TOP: solutions | colligative properties
KEY: vapor pressure of a solution | Raoult's law MSC: general chemistry
edition 21

70. When 1 mol of a nonvolatile nonelectrolyte is dissolved in 3 mol of a solvent, the vapor
pressure of the solution compared with that of the pure solvent is
A) 1/4.
B) 4/5.
C) 1/2.
D) 1/5.
E) 3/4.
OBJ: Calculate vapor-pressure lowering. (Example 12.9)
71. What is the vapor pressure at 20°C of an ideal solution prepared by the addition of 8.87 g of
the nonvolatile solute urea, CO(NH2)2, to 57.6 g of methanol, CH3OH? The vapor pressure
of pure methanol at 20°C is 89.0 mmHg.
A) 6.75 mmHg
B) 69.1 mmHg
C) 77.1 mmHg
D) 82.2 mmHg
E) 19.9 mmHg
KEY: vapor pressure of a solution | vapor pressure lowering MSC: general chemistry
72. What is the vapor pressure at 75°C of an aqueous solution prepared by the addition of 64.3 g
of the nonvolatile solute urea, CO(NH2)2, to 174 g of water? The vapor pressure of pure
water at 75°C is 290. mmHg.
A) 133 mmHg
B) 28.9 mmHg
C) 167 mmHg
D) 261 mmHg
E) 212 mmHg
KEY: vapor pressure of a solution | vapor pressure lowering MSC: general chemistry
73. Benzene, C6H6, and toluene, C6H5CH3, form ideal solutions. At 35°C the vapor pressure of
benzene is 160. torr and that of toluene is 50.0 torr. In an experiment, 67.6 g of benzene and
86.7 g of toluene are placed in a closed container at 35°C. At equilibrium, what is the
partial vapor pressure of toluene?
A) 108 torr
B) 83.3 torr
C) 24.0 torr
D) 76.7 torr
E) 26.0 torr
edition 22

ANS: E PTS: 1 DIF: difficult REF: 12.5
74. Benzene, C6H6, and toluene, C6H5CH3, form ideal solutions. At 35°C the vapor pressure of
benzene is 160. torr and that of toluene is 50.0 torr. In an experiment, 3.6 mol of benzene
and 5.5 mol of toluene are placed in a closed container at 35°C and allowed to come to
equilibrium. What is the mole fraction of toluene in the vapor phase?
A) 0.52
B) 0.68
C) 0.32
D) 0.14
E) 0.60
ANS: C PTS: 1 DIF: difficult REF: 12.5
75. A liquid–liquid solution is called an ideal solution if
I. it obeys PV = nRT.
II. it obeys Raoult's law.
III. solute–solute, solvent–solvent, and solute–solvent interactions are very similar.
IV. solute–solute, solvent–solvent, and solute–solvent interactions are quite
different.
A) I, III, IV
B) I, II, III
C) II, III only
D) I, II, IV
E) II, IV only
OBJ: Describe an ideal solution. TOP: solutions | colligative properties
76. A solution of two liquids, A and B, shows negative deviation from Raoult's law. This means
that
A) the two liquids have a positive heat of solution.
B) molecules of A interact more strongly with B than A molecules interact with A or
B molecules interact with B.
C) molecules of A interact strongly with other A-type molecules.
D) molecules of A interact weakly, if at all, with B molecules.
E) molecules of A hinder the strong interaction between B molecules.
edition 23

77. A solution of CF3H in H2CO is most likely to
A) be ideal.
B) not be ideal, but the deviations cannot be predicted.
C) show negative deviations from Raoult's law.
D) obey Raoult's law.
E) show positive deviations from Raoult's law.
78. The fact that the boiling point of a pure solvent is lower than the boiling point of a solution
of the same solvent is a direct consequence of the
A) freezing-point depression of the solution.
B) vapor pressure of the solution being higher than the vapor pressure of the pure
solvent.
C) osmotic pressure of the solvent being lower than the osmotic pressure of the
solution.
D) vapor pressure of the solution being lower than the vapor pressure of the pure
solvent.
E) osmotic pressure of the solvent being higher than the osmotic pressure of the
solution.
OBJ: Define boiling–point elevation and freezing-point depression.
TOP: solutions | colligative properties KEY: boiling point elevation
79. A solute added to a solvent raises the boiling point of the solution because
A) the temperature to cause boiling must be great enough to boil not only the solvent
but also the solute.
B) the solute particles raise the solvent's vapor pressure, thus requiring a higher
temperature to cause boiling.
C) the solute increases the volume of the solution, and an increase in volume requires
an increase in the temperature to reach the boiling point (derived from PV = nRT).
D) the solute particles lower the solvent's vapor pressure, thus requiring a higher
temperature to cause boiling.
E) two of these explanations are correct.
OBJ: Define boiling–point elevation and freezing-point depression.
edition 24

80. What is the freezing point of a 0.24 m solution of glucose, C6H12O6, in water? (Kf for water
is 1.858°C/m.)
A) 0.22°C
B) 0.45°C
C) –0.45°C
D) –0.22°C
E) –0.89°C
OBJ: Calculate boiling-point elevation and freezing-point depression. (Example 12.10)
TOP: solutions | colligative properties KEY: freezing point depression
81. What is the boiling-point change for a solution containing 0.432 mol of naphthalene (a
nonvolatile, nonionizing compound) in 250. g of liquid benzene? (Kb = 2.53°C/m for
benzene)
A) 4.37 °C
B) 5.86 °C
C) 0.273 °C
D) 1.46 °C
E) 1.093 °C
82. Substance A has a greater molar mass than substance B. If 50 g of substance A are dissolved
in 250 g of water in one beaker, and 50 g of substance B are dissolved in 250 g of water in
another beaker, then
A) the vapor pressure of solution A will be lower than the vapor pressure of
solution B.
B) the solution of A will freeze at a lower temperature than the solution of B.
C) the two solutions will have the same vapor pressure.
D) the boiling point of solution A will be lower than the boiling point of solution B.
E) the solution of A will have a higher osmotic pressure than the solution of B.
83. A solution consisting of 0.228 mol of methylbenzene, C6H5CH3, in 255 g of nitrobenzene,
C6H5NO2, freezes at –0.3°C. Pure nitrobenzene freezes at 6.0°C. What is the freezing-point
depression constant of nitrobenzene?
A) 1.1°C/m
B) 27°C/m
C) 14.0°C/m
D) 3.5°C/m
E) 7.0°C/m
edition 25

ANS: E PTS: 1 DIF: moderate REF: 12.6
84. What is the mass percent of ethylene glycol (HOCH2CH2OH) in a solution of ethylene
glycol in water that has a freezing point of –19.2°C? (Kf for water is 1.858°C/m.)
A) 99.8%
B) 39.1%
C) 64.1%
D) 60.1%
E) 10.3%
85. Which of the following methods cannot be used to determine the molar mass of a
nonelectrolyte?
A) measurement of the freezing-point depression of a solution of the compound
B) measurement of the boiling-point elevation of a solution of the compound
C) measurement of the pressure, temperature, volume, and mass of the compound in
the gaseous state
D) measurement of the x-ray diffraction of a pure crystal of the compound
E) measurement of the osmotic pressure of a solution of the compound
OBJ: Calculate the molecular mass of a solute from molality. (Example 12.11)
TOP: solutions | colligative properties MSC: general chemistry
86. Trimellitic acid is an organic acid that has a composition of 51.44% C, 2.88% H, and
45.68% O by mass. A 5.02-g sample of trimellitic acid dissolved in 20 g of acetone,
CH3COCH3, has a boiling point of 58.24°C. What is the molecular formula of trimellitic
acid? (Kb for acetone is 1.71°C/m, and pure acetone has a boiling point of 56.20°C.)
A) CH2O
B) C9H6O6
C) C3HO2
D) C18HO16
E) C6H2O4
OBJ: Calculate the molecular mass from freezing-point depression. (Example 12.12)
edition 26

87. When a 28.4-g sample of an unknown compound is dissolved in 500. g of benzene, the
freezing point of the resulting solution is 3.77°C. The freezing point of pure benzene is
5.48°C, and Kf for benzene is 5.12°C/m. Calculate the molar mass of the unknown
compound.
A) 145 g/mol
B) 170. g/mol
C) 85.0 g/mol
D) 340 g/mol
E) 16.6 g/mol
88. Thyroxine, an important hormone that controls the rate of metabolism in the body, can be
isolated from the thyroid gland. If 0.453 g of thyroxine is dissolved in 10.0 g of benzene, the
freezing point of the solution could be measured as 5.144°C. Pure benzene freezes at
5.444°C and has a value for the molal freezing-point-depression constant of Kf of 5.12°C/m.
What is the approximate molar mass of thyroxine?
A) 773 g/mol
B) 7.73 g/mol
C) 7.73 × 105
g/mol
D) 42.6 g/mol
E) 11.3 g/mol
89. If a 18.0-g sample of a nonelectrolyte is dissolved in 112.0 g of water, the resulting solution
will freeze at –0.94°C. What is the molar mass of the nonelectrolyte? (Kf for water is
1.858°C/m.)
A) 77 g/mol
B) 0.32 g/mol
C) 550 g/mol
D) 280 g/mol
E) 320 g/mol
edition 27

90. What is the molar mass of an aromatic hydrocarbon if 0.85 g of the compound depresses the
freezing point of 128 g of benzene by 0.37°C? (Kf for benzene is 5.12°C/m.)
A) 35 g/mol
B) 150 g/mol
C) 93 g/mol 92
D) 2100 g/mol
E) 140 g/mol
91. Which of the following will cause the calculated molar mass of a compound determined by
the freezing-point-depression method to be greater than the true molar mass?
A) When the solute was added, some was spilled on the lab bench.
B) Water gets into the solvent after the freezing point of the pure solvent is
determined.
C) Some of the solute molecules break apart.
D) The mass of solvent is smaller than that determined from the weighing.
E) all of the above
92. A compound containing carbon and nitrogen has a composition of 46.16% carbon and
53.84% nitrogen by mass. A solution prepared by dissolving 1.542 g of this compound in
30.00 g of carbon tetrachloride, CCl4, produces a solution that boils at 81.69°C. What is the
molecular formula of the compound? (Kb for CCl4 is 5.03°C/m, and pure CCl4 has a
freezing point of 76.72°C.)
A) C2N2
B) CN2
C) C3N3
D) CN
E) C2N4
ANS: A PTS: 1 DIF: difficult REF: 12.6
93. A compound containing sulfur, nitrogen, and hydrogen has a composition of 86.6% sulfur,
12.6% nitrogen, and 0.91% hydrogen by mass. A solution prepared by dissolving 2.072 g of
this compound in 35.00 g of bromoform, CHBr3, produces a solution that freezes at 3.97°C.
What is the molecular formula of the compound? (Kf for bromoform is 14.4°C/m, and pure
bromoform has a freezing point of 7.8°C.)
edition 28

A) SNH
B) S3N2H2
C) S6N2H2
D) S3NH
E) S2N2H2
ANS: C PTS: 1 DIF: difficult REF: 12.6
94. A cucumber is placed in a concentrated salt solution. What is most likely to happen?
A) Water will flow from the solution to the cucumber.
B) No change will occur.
C) Salt will flow into the cucumber.
D) Salt will precipitate out.
E) Water will flow from the cucumber to the solution.
OBJ: Describe a system where osmosis will take place.
TOP: solutions | colligative properties KEY: osmotic pressure
95. A red blood cell placed in pure water will swell because
A) the osmotic pressure is greater in the water than in the cell.
B) the osmotic pressure is the same in the cell and the water.
C) the osmotic pressure is greater in the cell than in the water.
D) water moves from a higher osmotic pressure to a lower osmotic pressure.
E) the vapor pressure of the water in the cell is greater than the vapor pressure of pure
water.
TOP: solutions | colligative properties KEY: hypotonic solution
96. What is reverse osmosis?
A) the application, to a dilute solution, of a pressure that is greater than the osmotic
pressure, such that solvent flows from the concentrated solution to the dilute
solution
B) the application, to a dilute solution, of a pressure that is greater than the osmotic
pressure, such that solute flows from the concentrated solution to the dilute
solution
C) the application, to a concentrated solution, of a pressure that is greater than the
osmotic pressure, such that solute flows from the concentrated solution to the
dilute solution
edition 29

D) the application, to a concentrated solution, of a pressure that is greater than the
osmotic pressure, such that solvent flows from the concentrated solution to the
dilute solution
E) the application, to a concentrated solution, of a pressure that is greater than the
osmotic pressure, such that solvent flows from the dilute solution to the
concentrated solution
97. A solution of water and a nonvolatile, nonionizing compound is placed in a tube with a
semipermeable membrane on one side. The tube is placed in a beaker of pure water. What
initial net effect will occur?
A) Nothing will move through the membrane either way.
B) Water will flow from the beaker to the tube.
C) Water will flow from the tube to the beaker.
D) Equilibrium will be immediately established.
E) The compound will pass through the membrane into the solution.
98. Determine the osmotic pressure of a solution that contains 0.014 g of a hydrocarbon solute
(molar mass = 340 g/mol) dissolved in benzene to make a 350-mL solution. The
temperature is 20.0°C.
A) 0.9 torr
B) 2.0 torr
C) 0.14 torr
D) 0.7 torr
E) 2.1 torr
OBJ: Calculate osmotic pressure. (Example 12.13)
99. A 2.4-g sample of a small protein having a molecular weight of 62,000 g/mol is dissolved in
59.6 mL of water at 29°C. What is the osmotic pressure of the solution?
(R = 0.0821 L · atm/(K · mol))
A) 12 mmHg
B) 760 mmHg
C) 1.2 mmHg
D) 47,000 mmHg
E) 0.016 mmHg
edition 30

TOP: solutions | colligative properties KEY: osmotic pressure | colligative properties
100. Osmotic pressure is
A) inversely proportional to mass fraction.
B) directly proportional to lattice energy.
C) inversely proportional to molality.
D) inversely proportional to mole fraction.
E) directly proportional to molarity.
101. Calculate the molecular weight of a small protein if a 0.24-g sample dissolved in 108 mL of
water has an osmotic pressure of 9.5 mmHg at 22°C. (R = 0.0821 L · atm/(K · mol))
A) 3.2 × 102
g/mol
B) 4.3 × 103
g/mol
C) 5.7 g/mol
D) 1.8 × 102
g/mol
E) 5.7 × 10–3
g/mol
102. To determine the molar mass of a small protein in the range of 20,000–40,000 g/mol, it
would be best to measure
A) the freezing point of the solvent and of the solution and the weight of the solute
and solvent.
B) the boiling point of the solvent and of the solution and the weight of the solute and
solvent.
C) the vapor pressure of the solvent and of the solution and the weight of the solute
and solvent.
D) the osmotic pressure of the solution and the weight of the solute and solvent.
E) the density of the protein and to make x-ray measurements.
edition 31

103. For a dilute solution of (NH4)3PO4, the van’t Hoff factor (i) would be approximately
A) 4.
B) 2.
C) 3.
D) 1.
E) 5.
OBJ: Determine the colligative properties of ionic solutions. (Example 12.14)
TOP: solutions | colligative properties NOT: REVISED
104. For a dilute solution of FeCl3, the van’t Hoff factor (i) would be approximately
A) 4.
B) 2.
C) 3.
D) 1.
E) 5.
TOP: solutions | colligative properties NOT: REVISED
105. Based on the formulas of the following solutes, which compound would have the smallest
van’t Hoff factor (i)?
A) Ca(NO3)2(aq)
B) K2SO4(aq)
C) Th(SO4)2(aq)
D) Al2(SO4)3(aq)
E) MgSO4(aq)
106. Which of the following solutes in aqueous solution would be expected to exhibit the
smallest freezing-point lowering (assuming ideal behavior)?
A) 0.1 m NaCl
B) 0.2 m CH3COOH
C) 0.05 m Al2(SO4)3
D) 0.1 m MgCl2
E) 0.25 m NH3
ANS: A PTS: 1 DIF: easy-moderate
REF: 12.8
edition 32

107. Which of the following solutions would have the highest osmotic pressure?
A) 0.15 M MgBr2
B) 0.15 M NaCl
C) 0.20 M C12H22O11
D) 0.20 M C6H12O6
E) 0.20 M CH3OH
108. What is the freezing point of an aqueous 1.66 m CaCl2 solution? (Kf for water is 1.858°C/m.)
A) 9.3°C
B) 3.1°C
C) –9.3°C
D) 0.0°C
E) –3.1°C
109. Which of the following amounts of solute, dissolved in 1.0 kg of water, creates a solution
with the lowest freezing temperature? (assuming ideal behavior)
A) 0.0015 mol of sulfuric acid, H2SO4
B) 0.0015 mol of H2SO3
C) 0.0030 mol of ethanol, C2H5OH
D) 0.0030 mol of methanol, CH3OH
E) 0.0015 mol of sucrose, C12H22O11
110. Which of the following solutes, dissolved in 1.0 kg of water, creates a solution that boils at
the highest temperature?
A) 0.010 mol H3PO4
B) 0.010 mol HClO4
C) 0.010 mol H2SO4
D) 0.010 mol HCl
E) 0.010 mol HF
edition 33

111. Which of the following solutes, dissolved in 1000 g of water, would provide a solution with
the lowest freezing point?
A) 0.030 mol of barium chloride, BaCl2
B) 0.030 mol of urea, CO(NH2)2
C) 0.030 mol of calcium sulfate, CaSO4
D) 0.030 mol of acetic acid, CH3COOH
E) 0.030 mol of ammonium nitrate, NH4NO3
112. Which of the following solutions has the lowest osmotic pressure?
A) 0.10 M Al(NO3)3
B) 0.20 M C6H12O6
C) 0.15 M Ba(NO3)2
D) 0.10 M CaCl2
E) 0.15 M Na2S
113. At 37°C, what is the osmotic pressure of a 0.59% NaCl by weight aqueous solution?
Assume the density of the solution is 1.0 g/mL. (R = 0.0821 L · atm/(K · mol))
A) 0.26 atm
B) 2.6 atm
C) 3.0 × 102
atm
D) 5.1 atm
E) 0.61 atm
114. For which of the following aqueous solutions would one expect to have the largest van’t
Hoff factor (i)?
A) 0.400 m K2SO4
B) 0.400 m NaCl
C) 0.400 m C6H12O6 (glucose)
D) 0.040 m K2SO4
E) 0.040 m NaCl
edition 34

115. The molal boiling-point constant for water is 0.51°C/molal. The boiling point of a 1.00 m
solution of Ca(NO3)2 should be increased by
A) exactly 1.53°C.
B) exactly 1.02°C.
C) somewhat less than 1.02°C.
D) exactly 0.51°C.
E) somewhat less than 1.53°C.
116. What type of colloid is formed when a liquid is dispersed in a gas?
A) foam
B) emulsion
C) aerosol
D) sol
E) gel
OBJ: Define colloid. TOP: solutions | colloid formation
KEY: colloid | types of colloid MSC: general chemistry
117. What type of colloid is formed when a gas is dispersed in a solid?
A) foam
B) aerosol
C) sol
D) emulsion
E) gel
118. What type of colloid is formed when a liquid is dispersed in a solid?
A) emulsion
B) gel
C) sol
D) foam
E) aerosol
edition 35

119. What type of colloid is formed when a solid is dispersed in a liquid?
A) emulsion
B) gel
C) aerosol
D) sol
E) foam
120. When a liquid is dispersed in another liquid, the resulting colloid is called a(n)
A) emulsion.
B) sol.
C) foam.
D) aerosol.
E) gel.
121. A suspension of silver particles in water is most likely to form what type of colloid?
A) aerosol
B) micelle
C) hydrophobic colloid
D) association colloid
E) hydrophilic colloid
OBJ: Give examples of hydrophilic colloids and hydrophobic colloids.
TOP: solutions | colloid formation KEY: colloid | hydrophobic colloid
122. Which of the following statements describes the process of coagulation?
A) The dispersed phase of an association colloid aggregates and forms a hydrophilic
colloid.
B) The continuous phase of a colloid aggregates and separates from the dispersed
phase.
C) The dispersed phase of an association colloid aggregates and forms a hydrophobic
colloid.
D) The dispersed phase of a colloid aggregates and separates from the continuous
phase.
E) The dispersed phase of an association colloid aggregates and forms a micelle.
OBJ: Describe coagulation. TOP: solutions | colloid formation
KEY: colloid | coagulation MSC: general chemistry
edition 36

123. A suspension of sodium dodecanoate, CH3(CH2)10COONa, in water is most likely to form
what type of colloid?
A) hydrophilic colloid
B) association colloid
C) emulsion
D) aerosol
E) hydrophobic colloid
OBJ: Explain how micelles can form an association colloid.
TOP: solutions | colloid formation KEY: colloid | association colloid
124. Synthetic detergent dispersed in water is an example of a(n)
A) micelle.
B) hydrophilic colloid.
C) coagulant.
D) hydrophobic colloid.
E) association colloid.
OBJ: Explain how micelles can form an association colloid.
TOP: solutions | colloid formation KEY: colloid | association colloid
edition 37

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