25) A solution is prepared by dissolving 10.0 g of benzene (C6H6) in 282 g of carbon tetrachloride (CCl4).
The concentration of benzene in this solution is ________ molal. The molar masses of C6H6 and CCl4 are
78.1 g/mol and 154 g/mol, respectively.
A) 4.54 × 10-4
B) 0.454
C) 0.0654
D) 0.0342
E) 3.42
26) At 20 °C, an aqueous solution that is 12.0% by mass in ammonium chloride has a density of
1.0344 g/mL. What is the molarity of ammonium chloride in the solution? The formula weight of NH4Cl
is 53.50 g/mol.
A) 2.55
B) 0.232
C) 2.32
D) 0.0862
E) 11.6
27) At 20 °C, a 3.13 M aqueous solution of ammonium chloride has a density of 1.0457 g/mL. What is the
molality of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g/mol.
A) 3.56
B) 0.0611
C) 3.13
D) 0.334
E) 16.00
28) At 20 °C, a 1.73 M aqueous solution of ammonium chloride has a density of 1.0257 g/mL. What is the
mass % of ammonium chloride in the solution? The formula weight of NH4Cl is 53.50 g/mol.
A) 1.85
B) 3.31
C) 1.68
D) 0.594
E) 9.00
29) The mole fraction of He in a gaseous solution prepared from 1.0 g of He, 6.5 g of Ar, and 10.0 g of Ne
is ________.
A) 0.28
B) 0.25
C) 0.20
D) 0.66
E) 0.86
30) The concentration of sodium chloride in an aqueous solution that is 2.13 M and that has a density of
1.01 g/mL is ________% by mass.
A) 2.11
B) 7.83
C) 124
D) 12.3
E) 14.2
31) A solution contains 33% phosphoric acid by mass. This means that ________.
A) 100 g of this solution contains 33 g of phosphoric acid
B) 1 mL of this solution contains 33 g of phosphoric acid
C) 1 L of this solution has a mass of 33 g
D) 1 L of this solution contains 33 mL of phosphoric acid
E) the density of this solution is 3.3 g/mL
32) Calculate the molality of a 21.6% (by mass) aqueous solution of phosphoric acid (H3PO4).
A) 2.81 m
B) 276 m
C) 5.62 m
D) 1.41 m
E) The density of the solution is needed to solve the problem.
33) Calculate the molarity of phosphoric acid (H3PO4) in a 22.1% (by mass) aqueous solution.
A) 0.0522 m
B) 0.0992 m
C) 0.0248 m
D) 0.0496 m
E) The density of the solution is needed to solve the problem.
34) Calculate the mole fraction of phosphoric acid (H3PO4) in a 29.1% (by mass) aqueous solution.
A) 0.0702
B) 0.0755
C) 0.140
D) 0.0351
E) The density of the solution is needed to solve the problem.
35) Calculate the molality of a 10.0% (by mass) aqueous solution of hydrochloric acid.
A) 2.40 m
B) 87.4 m
C) 0.791 m
D) 1.20 m
E) The density of the solution is needed to solve the problem.
36) Calculate the mole fraction of HCl in a 7.20% (by mass) aqueous solution.
A) 0.0369
B) 0.0383
C) 0.0739
D) 0.0185
E) The density of the solution is needed to solve the problem.
37) Calculate the molality of a 35.0% (by mass) aqueous solution of nitric acid.
A) 6.64
B) 538
C) 2.19
D) 3.32
E) The density of the solution is needed to solve the problem.
38) Calculate the mole fraction of nitric acid of a 18.6% (by mass) aqueous solution of nitric acid.
A) 0.0484
B) 0.0508
C) 0.0967
D) 0.0242
E) The density of the solution is needed to solve the problem.
39) A solution contains 51 ppm of benzene. The density of the solution is 1.00 g/mL. This means that
________.
A) there are 51 mg of benzene in 1.0 L of this solution
B) 100 g of the solution contains 51 g of benzene
C) 100 g of the solution contains 51 mg of benzene
D) the solution is 51% by mass of benzene
E) the molarity of the solution is 51 M
37
40) The concentration of sodium sulfate solution is 18.6% by mass. There are ________ g of sodium sulfate
present in a 236.5 g sample of this solution.
A) 44.0
B) 4400
C) 0.000786
D) 7.86
E) 1270
41) The concentration of lithium chlorate solution is 12.0% by mass. In a ________ g sample of this
solution, there are 238.5 g of dissolved lithium chlorate.
A) 1990
B) 28.6
C) 0.199
D) 5.03
E) 0.0503
42) The concentration of a solution of lithium chlorite dissolved in water is 12.5% by mass. In a
________ g sample of this solution, there are 52.5 g of water.
A) 60.0
B) 45.9
C) 0.00600
D) 23.8
E) 1.67
43) A solution is made by dissolving 4.92 g of glucose (C6H12O6) in to 165 mL of water. The molality of
this solution is ________ m, if the density of water is 1.00 g/mL.
A) 0.165
B) 0.331
C) 0.0827
D) 29.8
E) 0.00450
44) Which produces the greatest number of ions when one mole dissolves in water?
A) Na3PO4
B) KBr
C) NaMnO4
D) NH4Cl
E) glucose
45) The ideal value of i (van’t Hoff factor) for Na3PO4 is:
A) 4
B) 3
C) 2
D) 1
E) 5
46) Of the following, a 0.2 M aqueous solution of ________ will have the highest freezing point.
A) RbBr
B) K2SO4
C) Sr(NO3)2
D) (NH4)2SO4
E) Fe(NO3)2
47) Which of the following will have an ideal van’t Hoff factor (i) value of 1?
A) sucrose
B) NaF
C) LiNO3
D) NH4NO3
E) Li2PO4
48) Which produces the greatest number of ions when one mole dissolves in water?
A) K2SO4
B) NaF
C) LiMnO4
D) NH4Br
E) sucrose
49) A solution is prepared by dissolving 2.00 g of glycerin (C3H8O3) in 201 g of ethanol (C2H5OH). The
freezing point of the solution is ________°C. The freezing point of pure ethanol is -114.6 °C at 1 atm. The
molal-freezing-point-depression constant (Kf) for ethanol is 1.99 °C/m. The molar masses of glycerin and
of ethanol are 92.1 g/mol and 46.1 g/mol, respectively.
A) -116.6
B) 0.215
C) -112.6
D) -114.4
E) -114.8
50) The vapor pressure of pure water at 25 °C is 23.8 torr. Determine the vapor pressure (torr) of water at
25 °C above a solution prepared by dissolving 25 g of urea (a nonvolatile, non-electrolyte,
MW = 60.0 g/mol) in 75 g of water.
A) 2.9
B) 0.42
C) 22
D) 27
E) 0.91
51) The freezing point of ethanol (C2H5OH) is -114.6 °C. The molal freezing point depression constant for
ethanol is 2.00 °C/m. What is the freezing point (°C) of a solution prepared by dissolving 50.0 g of
glycerin (C3H8O3, a nonelectrolyte) in 200.0 g of ethanol?
A) -115.0
B) -5.43
C) -132.3
D) -120.0
E) -114.6
52) Calculate the freezing point of a 0.09500 m aqueous solution of glucose. The molal freezing-point-
depression constant of water is 1.86 °C/m.
A) 0.0475
B) 0.106
C) -0.0562
D) -0.177
E) -0.354
53) Calculate the freezing point of a 0.05500 m aqueous solution of NaNO3. The molal freezing-point-
depression constant of water is 1.86 °C/m.
A) 0.0286
B) -0.106
C) 0.106
D) -0.0562
E) -0.205
54) Calculate the freezing point of a solution containing 20 grams of KCl and 2200.0 grams of water. The
molal-freezing-point-depression constant (Kf) for water is 1.86 °C/m.
A) -0.45 °C
B) +0.45 °C
C) -0.23 °C
D) +0.23 °C
E) 1.23 °C
55) The osmotic pressure of a solution formed by dissolving 45.0 mg of aspirin C9H8O4) in 0.250 L of
water at 25 °C is ________ atm.
A) 24.5
B) 2.05 × 10-3
C) 0.0245
D) 4.41
E) 2.48
56) A solution is prepared by adding 40.00 g of lactose (milk sugar) to 110.0 g of water at 55 °C The partial
pressure of water above the solution is ________ torr. The vapor pressure of pure water at 55 °C is 118.0
torr. The MW of lactose is 342.3 g/mol.
A) 2.216
B) 125.5
C) 225.9
D) 115.8
E) 86.5
13.4 Short Answer Questions
1) The formula weight of FeCl3∙6H2O is ________.
2) Water (H2O) and the alcohol methanol (CH3OH) are infinitely soluble in each other. The primary
intermolecular force responsible for this is ________.
3) For a dilute aqueous solution, a concentration of 1 ppm also corresponds to a concentration of 1
________ per liter of solution.
4) For a dilute aqueous solution, a concentration of 1 ppb also corresponds to a concentration of 1
________ per liter of solution.
5) What is the osmotic pressure (in atm) of a 0.040 M solution of a non-electrolyte at 30.0 °C?
6) Physical properties of a solution that depend on the quantity of the solute particles present, but not the
kind or identity of the particles, are termed ________ properties.
7) A solution contains 150.8 grams of NaCl in 678.3 grams of water. Calculate the vapor pressure
lowering (in torr) of the solution at 25.0 °C. (Note: The vapor pressure of pure water at 25.0 °C is 23.76
torr.)
8) A solution contains 150.8 grams of NaCl in 678.3 grams of water. Calculate the vapor pressure of water
(in torr) over the solution at 25.0 °C. (Note: The vapor pressure of pure water at 25.0 °C is 23.76 torr.)
9) The phenomenon used to differentiate colloids and true solutions is called the ________ effect.
13.5 True/False Questions
1) A solution with a solute concentration greater than the solubility is called a supercritical solution.
2) Adding a nonvolatile solute to a solution decreases the vapor pressure of the solution.
3) After swimming in the ocean for several hours, swimmers noticed that their fingers appeared to be
very wrinkled. This is an indication that seawater is supertonic relative to the fluid in cells.
4) The value of the boiling-point-elevation constant (Kb) depends on the identity of the solvent.
5) Emulsifying agents typically have a hydrophobic end and a hydrophilic end.