69) 100 mL of LiNO3(aq), 0.241 M is mixed with 240 mL of 0.618 M Ca(NO3)2(aq). What is the final
concentration of NO3–(aq) in the solution?
A) 0.508 M
B) 1.01 M
C) 0.943 M
D) 0.756 M
E) 1.38 M
70) A 1.38 M solution of nitric acid (63. g/mol) in water (18.0 g/mol) has a density of 1.04 g/mL. What is
the mole fraction of nitric acid in the solution?
A) 0.0254
B) 0.0239
C) 0.0261
D) 0.0228
E) 0.0233
71) What is the molarity of a saturated solution of potassium sulfate if the solubility is 13 g per 100 g H2O
at 25 °C? The density of the solution is 1.1 g/mL
A) 0.14 M
B) 1.1 M
C) 0.96 M
D) 0.73 M
E) 0.79 M
72) The solubility of ammonium permanganate is 7.90 g/100 mL of water. 29.0 grams of ammonium
permanganate are placed in a container and 220 mL of water is added. The liquid is allowed to stand in
contact with the solid until equilibrium is achieved and then the liquid is poured off. What is the weight
of solid left?
A) 17.4 g
B) 79.0 g
C) 7.90 g
D) 11.6 g
E) 29.0 g
73) A saturated solution of ammonium sulfate, (NH4)2SO4, in water at 30 °C contains 78.0 g (NH4)2SO4
per 100.0 g H2O. What is the molality of this solution?
A) 0.780 m
B) 1.69 m
C) 0.590 m
D) 0.0590 m
E) 5.90 m
74) The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21.0 mmHg and 45.2 mmHg,
respectively, at 25 °C. Calculate the partial pressure of isopropyl alcohol above a solution in which the
mole fraction of propyl alcohol is 0.250.
A) 33.9 mmHg
B) 11.3 mmHg
C) 5.25 mmHg
D) 15.8 mmHg
75) The concentration unit used in Raoult’s Law calculations is ________.
A) mole fraction
B) percent by weight
C) molarity
D) molality
E) grams per L
76) If a solution containing 4 mols of A and 6 mol of B boils at 85 °C and 1 atm of pressure, and the vapor
pressure of pure A at 85 °C is 500 mmHg, what is the vapor pressure of pure B at this temperature?
A) 933 mmHg
B) 336 mmHg
C) 260 mmHg
D) 576 mmHg
E) 960 mmHg
77) Given that the vapor pressure of pure n-hexane and pure n-heptane at 25 °C are 151.4 mmHg and
45.62 mmHg respectively, calculate the total vapor pressure above a solution containing only n-hexane
and n-heptane in which the mole fraction of n-hexane is 0.600.
A) 87.9 mmHg
B) 197 mmHg
C) 106 mmHg
D) 109 mmHg
E) 170 mmHg
78) The vapor pressures of pure hexane and pure heptane at 25 °C are 151.4 mmHg and 45.62 mmHg
respectively. A solution contains 0.800 mol fraction n-hexane and 0.200 mol fraction n-heptane. What is
the composition of the vapor in equilibrium with this solution at 25 °C?
A) 80.0% hexane, 20.0% heptane
B) 50.0% hexane, 50.0% heptane
C) 77.0% hexane, 23.0% heptane
D) 45.0% hexane, 55.0% heptane
E) 93.0% hexane, 7.0% heptane
79) A mixture of benzene and toluene has a total vapor pressure at 25 °C of 45.06 mmHg. What is the
partial pressure of benzene in this solution? The vapor pressure of pure benzene and pure toluene at 25
°C are 95.03 mmHg and 28.40 mmHg respectively.
A) 0.7500 mmHg
B) 23.76 mmHg
C) 0.3217 mmHg
D) 21.30 mmHg
E) 16.66 mmHg
80) What is the correct value for the weight of Na3PO4 needed to make 100 mL of a 0.50 molar aqueous
solution?
A) 16.4 g
B) 8.2 g
C) 0.05 g
D) 82 g
E) 4.1 g
81) Determine the osmotic pressure at 25 °C of an aqueous solution that is 0.028 M NaNO3.
A) 1.37 atm
B) 0.685 atm
C) 0.0729 atm
D) 0.0364 atm
E) 2.06 atm
82) A solution of nonvolatile solute has an osmotic pressure of 141 mmHg at 25 °C. What is the molarity
of the solution?
A) 0.00759 M
B) 5.76 M
C) 0.0904 M
D) 0.0339 M
E) 0.174 M
83) An isotonic solution will produce an osmotic pressure of 7.84 atm measured against pure water at
human body temperature (37.0 °C). How many grams of sodium chloride must be dissolved in a liter of
water to produce an isotonic solution?
A) 75.5 g
B) 151 g
C) 2.58 g
D) 9.00 g
E) 18.0 g
84) A membrane permeable to water but not to glucose (C6H12O6) separates two aqueous solutions.
Solution A is 0.156 M glucose and solution B contains pure water. There will be a net flow of water
molecules across the membrane from solution B to solution A until equilibrium is established across the
membrane. What pressure would have to be applied to solution A to prevent osmosis flow across the
membrane at 25 °C?
A) 1.00 atm
B) 3.82 atm
C) 0.320 atm
D) 1.91 atm
E) 0.382 atm
85) What is the osmotic pressure in mmHg of 2.00 L of a 1.34 × 10-3 M solution at 25 °C if four moles of
ions are produced in aqueous solution for every mole of solute dissolved?
A) 62.3 mmHg
B) 1.99 × 103 mmHg
C) 99.6 mmHg
D) 1.31 mmHg
E) 9.96 × 103 mmHg
86) Exactly 375.0 mg of an unknown protein is dissolved in enough water to give 50.00 mL of solution
and the osmotic pressure determined as 3.25 mmHg at 298 K. Estimate the molar mass of this protein.
A) 42,900 g/mol
B) 3,600 g/mol
C) 56,400 g/mol
D) 139,000 g/mol
87) The concentration unit used in determining freezing point depression and boiling point elevation is
________.
A) molality
B) mole fraction
C) normality
D) molarity
E) weight fraction
88) The concentration unit used to calculate boiling point elevation is ________.
A) molarity
B) solubility
C) molality
D) mole fraction
E) weight fraction
89) The freezing point of pure benzene was measured as 5.49 °C. With the same benzene and the same
equipment, the freezing point of a solution containing 6.60 g of an unknown molecular compound in 140
g of benzene was found to be 2.35 °C. The cryoscopic constant, Kf, for benzene is 5.12 °C kg/mol.
Calculate the mole weight of the unknown.
A) 103 g/mol
B) 76.9 g/mol
C) 44.0 g/mol
D) 28.9 g/mol
E) 17.4 g/mol
90) 0.25 mol of a nonvolatile, nonionic solute dissolved in 300 g of water (Kf = 1.86 °C m–1) will lower the
freezing point how many degrees?
A) 0.65 °C
B) 2.2 °C
C) 0.14 °C
D) 1.6 °C
E) 3.2 °C
91) How many moles of ethylene glycol must be dissolved in 500 g of water (Kf = 1.86 °C m-1) to lower
the freezing point to -5.00 °C?
A) 18.6 mol
B) 2.69 mol
C) 0.268 mol
D) 3.73 mol
E) 1.34 mol
92) Predict the freezing point of a solution prepared by dissolving 8.9 g MgCl2 in 98 g H2O. Kf for water
is 1.86 °C m-1.
A) 3.5 °C
B) -3.5 °C
C) 5.3 °C
D) -5.3 °C
E) -0.51 °C
93) The freezing point of pure benzene was measured as 5.49 °C. With the same benzene and same
equipment, the freezing point of a solution containing 6.582 g of an unknown molecular compound (sold
in the store as “moth crystals”) in 100.203 grams of benzene was found to be 3.48 °C. The cryoscopic
constant, Kf, for benzene is 5.12 °C kg/mole. Calculate the molar mass weight of the unknown.
A) 37.5 g/mol
B) 16.7 g/mol
C) 96.6 g/mol
D) 70.4 g/mol
E) 167 g/mol
94) What mass in grams of a molecular substance (molar mass = 50.0 g/mol) must be added to 500 g of
water to produce a solution that boils at 101.56 °C? [Kb(water) = 0.512 °C m-1]
A) 76.2 g
B) 150.0 g
C) 100.0 g
D) 30.0 g
E) 152.4 g
95) 0.0800 g of a compound with the empirical formula C2H2N is dissolved in 10.00 g benzene. The
resulting solution freezes at 4.99 °C. Benzene freezes at 5.48 °C and has a freezing point depression
constant of Kf = 4.90 °C/m. What is the molecular formula of the compound?
A) C3H2N
B) C3H3N
C) C4H4N2
D) C6H6N3
E) C8H8N4
96) An unknown compound is composed of 65.44% C, 29.07% O, and 5.49% H. A sample weighing 5.34 g,
when dissolved in 60.00 g H2O, lowers the freezing point to -0.600 °C. What is the molecular formula of
the compound? (Kf for water = 1.86 °C/m; C = 12.0, O = 16.0, H = 1.0 g/mol).
A) C3H3O
B) CHO
C) C14H11O6
D) C5H5O5
E) C7H5O3
97) A saline solution begins to freeze at -1.13 °C. Express the concentration of NaCl in this solution in
mass %. Kf for water is 1.86 °C m-1.
A) 3.48%
B) 1.74%
C) 0.870%
D) 17.8%
E) 8.90%
98) Two solutions contain the same amount of water as a solvent. One solution contains 0.5 mol glucose
(C6H12O6) while the other one contains 0.2 mol of CaCl2 . If the freezing points of both solutions are the
same, determine the van’t Hoff i factor for CaCl2 solution.
A) 2.50
B) 3
C) 1.50
D) 2.75
E) 0.75
99) 3.2 grams of a compound with a molar mass of 96 g/mol dissolved in 50 grams of water gave a
solution that freezes at -1.50 °C. Kf for water is 1.86 °C/m. The van’t Hoff i factor for this solution is
________.
A) 0.83
B) 1.2
C) 0.21
D) 0.17
E) 2.0
100) The freezing point of a solution made by dissolving 8.9 g of MgCl2 in 98 g H2O is -4.3 °C. Kf for
water is 1.86 °C m-1. The van’t Hoff i factor for this solution is ________.
A) 1.2
B) 2.7
C) 2.4
D) 2.0
E) 3.0
101) What volume of an aqueous solution of 0.716 mol L-1 KBr is needed to provide 30.5 g of KBr?
A) 21.8 mL
B) 42.7 mL
C) 184 mL
D) 357 mL
102) What volume of an aqueous solution of 3.00 mol L-1 CH3OH is needed to provide 0.220 mol of
CH3OH?
A) 1.52 mL
B) 13.6 mL
C) 73.3 mL
D) 660 mL
103) To make a 0.500 mol L-1 solution, one could take 0.500 moles of solute and add:
A) 1.00 L of solvent
B) 1.00 kg of solvent
C) enough solvent to make 1.00 L of solution
D) enough solvent to make 1.00 kg of solution
104) How many grams of KBr are required to make 350. mL of a 0.115 mol L-1 KBr aqueous solution?
A) 0.338 g
B) 3.04 g
C) 4.79 g
D) 40.3 g
105) What is the molality of a glucose solution prepared by dissolving 18.0 g of glucose, C6H12O6, in
125.9 g of water?
A) 7.94 × 10–4 mol kg-1
B) 0.143 mol kg-1
C) 0.695 mol kg-1
D) 0.794 mol kg-1
106) To make a 2.00 mol kg-1 solution, one could take 2.00 moles of solute and add:
A) 1.00 L of solvent
B) 1.00 kg of solvent
C) enough solvent to make 1.00 L of solution
D) enough solvent to make 1.00 kg of solution
107) What molality of pentane is obtained by dissolving 15 g pentane, C5H12, in 245.0 g hexane, C6H14?
A) 0.058 mol kg-1
B) 0.068 mol kg-1
C) 0.85 mol kg-1
D) 61 mol kg-1
108) A solution of LiCl in water has xLiCl = 0.0900. What is the molality?
A) 4.46 mol kg-1 LiCl
B) 5.00 mol kg-1 LiCl
C) 5.49 mol kg-1 LiCl
D) 9.89 mol kg-1 LiCl
109) A solution is prepared by adding 1.43 mol of KCl to 889 g of water. The concentration of KCl is
________ mol kg-1.
A) 1.61 × 10-3
B) 622
C) 0.622
D) 1.27 × 103
E) 1.61
110) A solution is prepared by dissolving 16.2 g of benzene ( ) in 282 g of carbon tetrachloride
The concentration of benzene in this solution is ________ molal. The molar masses of and
are and respectively.
A) 7.36 ×
B) 0.736
C) 0.102
D) 0.0543
E) 5.43
111) What is the weight percent of vitamin C in a solution made by dissolving 6.50 g of vitamin C,
C6H8O6, in 55.0 g of water?
A) 0.547%
B) 1.21%
C) 10.6%
D) 11.8%
112) What is the weight percent of a caffeine solution made by dissolving 8.35 g of caffeine, C8H10N4O2,
in 75 g of benzene, C6H6?
A) 0.010%
B) 0.011%
C) 10%
D) 11%
113) How much water must be added to 40.0 g of CaCl2 to produce a solution that is 35.0 wt% CaCl2?
A) 54.0 g
B) 74.3 g
C) 87.5 g
D) 114 g
114) A solution of LiCl in water is 20.0 wt% LiCl. What is the mole fraction of LiCl? Assume the density of
the solution is 1.00 g mL-1.
A) 0.0960
B) 0.106
C) 0.472
D) 4.44
115) What is the mole fraction of ethanol in a solution made by dissolving 29.2 g of ethanol, C2H5OH, in
53.6 g of water?
A) 0.176
B) 0.213
C) 0.352
D) 0.545
116) What is the mole fraction of I2 in a solution made by dissolving 55.6 g of I2 in 245 g of hexane,
C6H14?
A) 0.0715
B) 0.0770
C) 0.133
D) 0.154
117) What is the mole fraction of oxygen in a gas mixture that is 37% oxygen and 63% nitrogen by
volume?
A) 0.34
B) 0.37
C) 0.25
D) 0.52
118) A solution is 2.25% by weight NaHCO3. How many grams of NaHCO3 are in 150.0 g of solution?
A) 1.50 g
B) 3.38 g
C) 66.7 g
D) 225 g
119) At 20 °C, an aqueous solution that is 24.0% by mass in ammonium chloride has a density of
What is the molarity of ammonium chloride in the solution? The formula weight of Cl
is
A) 5.90
B) 0.479
C) 4.79
D) 0.0445
E) 22.5
120) At 20 °C, a 2.32 mol L-1 aqueous solution of ammonium chloride has a density of
What is the molality of ammonium chloride in the solution? The formula weight of Cl is
A) 2.55
B) 0.0449
C) 2.32
D) 0.446
E) 12.00
121) At 20 °C, a 0.376 mol L-1 aqueous solution of ammonium chloride has a density of
What is the mass % of ammonium chloride in the solution? The formula weight of Cl is
A) 0.381
B) 0.705
C) 0.374
D) 2.68
E) 2.00
122) A solution is prepared by dissolving 40.0 g of sucrose, C12H22O11, in 250. g of water at 25 °C. What
is the vapour pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?
A) 0.198 mmHg
B) 20.5 mmHg
C) 23.6 mmHg
D) 24.0 mmHg
123) A KCl solution is prepared by dissolving 25.0 g KCl in 250.0 g of water at 25 °C. What is the vapour
pressure of the solution if the vapour pressure of water at 25 °C is 23.76 mmHg?
A) 21.6 mmHg
B) 22.7 mmHg
C) 23.2 mmHg
D) 24.9 mmHg
124) At a given temperature the vapour pressures of benzene and toluene are 183 mmHg and 59.2
mmHg, respectively. Calculate the total vapour pressure over a solution of benzene and toluene with
xbenzene = 0.580.
A) 106 mmHg
B) 121 mmHg
C) 131 mmHg
D) 242 mmHg
125) Which of the following solutions will have the lowest freezing point?
A) 0.010 mol kg-1 K Br
B) 0.010 mol kg-1 Na2CO3
C) 0.035 mol kg-1 CH3CH2OH
D) 0.015 mol kg-1 BaCl2
126) What is the expected freezing point of a 0.50 mol kg-1 solution of Li2SO4 in water? Kf for water is
1.86 °C m-1.
A) -0.93 °C
B) -1.9 °C
C) -2.8 °C
D) -6.5 °C
127) Calculate the freezing point of a solution of 40.0 g methyl salicylate, C7H6O2, dissolved in 800. g of
benzene, C6H6. and the freezing point is 5.50 °C for benzene.
A) -2.09 °C
B) 2.09 °C
C) 3.41 °C
D) 7.59 °C
128) What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? Kf for water is
A) -0.140 °C
B) -1.40 °C
C) -2.80 °C
D) -4.18 °C
129) An aqueous solution has a normal boiling point of 103.0 °C. What is the freezing point of this
solution? For water and
A) -0.82 °C
B) -3.0 °C
C) -3.6 °C
D) -11 °C
130) A solution is prepared by adding 30.00 g of lactose (milk sugar) to 110.0 g of water at The
partial pressure of water above the solution is ________ Torr. The vapour pressure of pure water at 55 °C
is 0.1553 bar. The MW of lactose is
A) 1.670
B) 94.1
C) 169.4
D) 116.3
E) 92.7
31
131) A solution is prepared by dissolving 7.00 g of glycerin ( ) in 201 g of ethanol The
freezing point of the solution is ________ °C. The freezing point of pure ethanol is . The molal
freezing point depression constant ( ) for ethanol is The molar masses of glycerin and of
ethanol are 92.1 g mol-1 and 46.1 g mol-1, respectively.
A) -121.3
B) 0.752
C) -107.9
D) -113.8
E) -115.4
132) Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water. The
molal freezing point depression constant ( ) for water is
A) -0.45 °C
B) +0.45 °C
C) -0.23 °C
D) +0.23 °C
E) 1.23 °C