AP Chemistry
Ch. 13 Practice test
1) The process of solute particles being surrounded by solvent particles is known as __________.
A) salutation
B) agglomeration
C) solvation
D) agglutination
E) dehydration
Answer: C Sec. 13.1
2) The solubility of oxygen gas in water at 25 °C and 1.0 atm pressure of oxygen is 0.041 g/L The solubility of oxygen in water at 3.0 atm
and 25 °C is __________ g/L.
A) 0.041
B) 0.014
C) 0.31
D) 0.12
E) 3.0
Answer: D Sec. 13.3
3) The solubility of nitrogen gas in water at 25 °C and a nitrogen pressure of 1.0 atm is 6.9 × 10-4 M The solubility of nitrogen in water at a
nitrogen pressure of 0.80 atm is __________ M.
A) 5.5 × 10-4
B) 8.6 × 10-4
C) 1.2 × 103 D) 3.7 × 10-3 E) 0.80
Answer: A Sec. 13.3
4) On a clear day at sea level, with a temperature of 25 °C, the partial pressure of N2 in air is 0.78 atm and the concentration of nitrogen in
water is 5.3 × 10-4 M . When the partial pressure of N2 is __________ atm, the concentration in water is 1.1 × 10-3M .
A) 0.63 atm
B) 0.78 atm
C) 1.0 atm
D) 2.1 atm
E) 1.6 atm
Answer: E Sec. 13.3
5) A sample of potassium nitrate (49.0 g) is dissolved in 101 g of water at 100 °C with precautions taken to avoid evaporation of any water.
The solution is cooled to 30.0 °C and a small amount of precipitate is observed. This solution is __________.
A) hydrated
B) placated
C) saturated
D) unsaturated
E) supersaturated
Answer: C Sec. 13.3
6) The solubility of MnSO4 monohydrate in water at 20 °C is 70.0 g per 100.0 mL of water. A solution at 20 °C that is 4.22 M in MnSO4
monohydrate is best described as a(n) __________ solution. The formula weight of MnSO 4 monohydrate is 168.97 g/mol.
A) hydrated
B) solvated
C) saturated
D) unsaturated
E) supersaturated
Answer: E Sec. 13.3
7) The concentration of urea in a solution prepared by dissolving 16 g of urea in 39 g of H 2 O is __________% by mass. The molar mass of
urea is 60.0 g/mol.
A) 29
B) 41
C) 0.29
D) 0.41
E) 0.48
Answer: A Sec. 13.4
8) The concentration of nitrate ion in a solution that contains 0.900 M aluminum nitrate is __________ M.
A) 0.900
B) 0.450
C) 0.300
D) 2.70
E) 1.80
Answer: D Sec. 13.4
9) The concentration of KBr in a solution prepared by dissolving 2.21 g of KBr in 897 g of water is __________ molal.
A) 2.46
B) 0.0167
C) 0.0207
D) 2.07 × 10-5
E) 0.0186
Answer: C Sec. 13.4
10) The concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in 200 g of C2 H6O is __________ M. The density of
the solution is 0.79 g/mL.
A) 21 B) 0.93
C) 0.58
D) 6.0 × 10-4
E) 1.72
Answer: C Sec. 13.4
11) The mole fraction of urea (MW = 60.0 g/mol) in a solution prepared by dissolving 16 g of urea in 39 g of H 2 O is __________.
A) 0.58
B) 0.37
C) 0.13
D) 0.11
E) 9.1
Answer: D Sec. 13.4
12) The concentration of urea (MW = 60.0 g/mol) in a solution prepared by dissolving 16 g of urea in 39 g of H 2 O is __________ molal.
A) 96
B) 6.9
C) 0.68
D) 6.3
E) 0.11
Answer: B Sec. 13.4
13) What is the molarity of sodium chloride in solution that is 13.0% by mass sodium chloride and that has a density of 1.10 g/mL?
A) 143
B) 2.45
C) 2.56
D) 2.23
E) 1.43 × 10-2
Answer: B Sec. 13.4
14) The vapor pressure of pure ethanol at 60 °C is 0.459 atm. Raoult's Law predicts that a solution prepared by dissolving 10.0 mmol
naphthalene (nonvolatile) in 90.0 mmol ethanol will have a vapor pressure of __________ atm.
A) 0.498
B) 0.413
C) 0.790
D) 0.367
E) 0.0918
Answer: B Sec. 13.5
15) The vapor pressure of pure water at 25 °C is 23.8 torr. What is the vapor pressure (torr) of water above a solution prepared by dissolving
18.0 g of glucose (a nonelectrolyte, MW = 180.0 g/mol) in 95.0 g of water?
A) 24.3
B) 23.4
C) 0.451
D) 0.443
E) 23.8
Answer: B Sec. 13.5
16) The freezing point of ethanol (C2 H5OH) 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 g of ethanol?
A) -115
B) -5.42
C) -132.3
D) -120.0
E) -114.6
Answer: D Sec. 13.5
17) What is the freezing point (°C) of a solution prepared by dissolving 11.3 g of Ca(NO3 )2
(formula weight = 164 g/mol) in 115 g of water? The molal freezing point depression constant for
water is 1.86 °C/m.
A) -3.34
B) -1.11
C) 3.34
D) 1.11
E) 0.00
Answer: A Sec. 13.5
18) A solution containing 10.0 g of an unknown liquid and 90.0 g water has a freezing point of -3.33 °C.
Given K f = 1.86°C/m for water, the molar mass of the unknown liquid is ________ g/mol.
A) 69.0
B) 333
C) 619
D) 161
E) 62.1
Answer: E Sec. 13.5
19) Determine the fraction of ionization of HX if a solution prepared by dissolving 0.020 mol of HX in 115 g of water freezes at -0.47 °C.
The molal freezing-point-depression constant of water is 1.86 °C/m.
A) 0.044
B) 0.30
C) 0.45
D) 1.45
E) 0.348
Answer: C Sec. 13.5
20) The dissolution of gases in water is virtually always exothermic because __________.
A) one of the two endothermic steps (separation of solute particles) in the solution-formation process is unnecessary
B) the exothermic step in the solution-formation process is unnecessary
C) gases react exothermically with water
D) neither of the two endothermic steps in the solution-formation process is necessary
E) all three steps in the solution-formation process are exothermic
Answer: A Sec. 13.1
21) Formation of solutions where the process is endothermic can be spontaneous provided that __________.
A) they are accompanied by another process that is exothermic
B) they are accompanied by an increase in order
accompanied by an increase in disorder
D) the solvent is a gas and the solute is a solid
E) the solvent is water and the solute is a gas
Answer: C Sec. 13.1
22) The phrase "like dissolves like" refers to the fact that __________.
A) gases can only dissolve other gases
B) polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes
C) solvents can only dissolve solutes of similar molar mass
D) condensed phases can only dissolve other condensed phases
E) polar solvents dissolve nonpolar solutes and vice versa
Answer: B Sec. 13.1
C) they are
23) Ammonium nitrate (NH4NO3) dissolves readily in water even though the dissolution is endothermic
by 26.4 kJ/mol. The solution process is spontaneous because __________.
A) the vapor pressure of the water decreases upon addition of the solute
B) osmotic properties predict this behavior
C) of the decrease in enthalpy upon addition of the solute
D) of the increase in enthalpy upon dissolution of this strong electrolyte
E) of the increase in disorder upon dissolution of this strong electrolyte
Answer: E
Diff: 2 Page Ref: Sec. 13.1
24) In a saturated solution of a salt in water, __________.
A) the rate of crystallization > the rate of dissolution
B) the rate of dissolution > the rate of crystallization
C) seed crystal addition may cause massive crystallization
D) the rate of crystallization = the rate of dissolution
E) addition of more water causes massive crystallization
Answer: D Sec. 13.2
25) Which one of the following substances would be the most soluble in CCl4 ?
A) CH3CH2OH
B) H 2 O
C) NH3 D) C10 H 22
E) NaCl
Answer: D Sec. 13.3
26) Which one of the following substances is more likely to dissolve in CCl4 ?
A) CBr4
B) HBr
C) HCl
D) CH3CH2OH
E) NaCl
Answer: A Sec. 13.3
27) Which one of the following is most soluble in water?
A) CH3OH B) CH3CH2 CH2 OH C) CH3CH2OH
D) CH3CH2 CH2 CH2 OH
Answer: A Sec. 13.3
E) CH3CH2 CH2 CH2 CH2 OH
28) Which one of the following concentration units varies with temperature?
A) molarity
B) mass percent
C) mole fraction
D) molality
E) all of the above
Answer: A Sec. 13.4
29) A 1.35 m aqueous solution of compound X had a boiling point of 101.4°C. Which one of the following could be compound X? The
boiling point elevation constant for water is 0.52°C/m.
A) CH3CH2OH
B) C6 H12O6 C) Na 3PO4 D) KCl
E) CaCl2
Answer: D Sec. 13.5
30) Colligative properties of solutions include all of the following except __________.
A) depression of vapor pressure upon addition of a solute to a solvent
B) elevation of the boiling point of a solution upon addition of a solute to a solvent
C) depression of the freezing point of a solution upon addition of a solute to a solvent
D) an increase in the osmotic pressure of a solution upon the addition of more solute
E) the increase of reaction rates with increase in temperature
Answer: E Sec. 13.5
13  Solutions
PRACTICE
6.
A 1.25 M Cu(NO3)2 (molar mass = 187.56 g/mol)
solution has a density of 1.19 g/cm3. What is the
TEST
weight percent Cu(NO3)2 of the solution?
1.
What is the molality of 7.80% by weight glucose
a) 1.88%
d) 14.3%
(C6H12O6 molar mass = 180.16 g/mol) solution?
b) 2.36%
e) 19.9%
a) 0.470 m
d) 0.0454 m
c) 10.5%
b) 0.845 m
e) 0.0844 m
7.
c) 0.0432 m
Hydrobromic acid (molar mass = 80.9 g/mol) is
commercially available in a 34.0 mass percent solution
2.
The mol fraction of NH4Cl in a solution is 0.0311.
which has a density of 1.31 g/cm3. What is the
What is its molality?
molarity of the commercially available hydrobromic
(The molar mass of water is 18.016 g/mol.)
acid?
a) 1.78 m
d) 0.562 m
a) 2.75 M
d) 9.35 M
b) 1.66 m
e) 0.0983 m
b) 4.45 M
e) 10.2 M
c) 5.50 M
c) 0.969 m
3.
What is the mol fraction Na2SO4 in a solution which is
8.
11.5% by weight Na2SO4 (molar mass Na2SO4 =
water system is 0.050 parts per million. If the arsenic
142.06 g/mol and H2O = 18.016 g/mol)?
is present as AsCl3, how many grams of arsenic
a) 0.0810
d) 0.0173
chloride could be present in a system that contains 8.2
b) 0.0914
e) 0.0162
x 105 Liters?
c) 0.0745
4.
The maximum contamination level of arsenic ion in a
a) 0.55 g
d) 62 g
b) 7.3 g
e) 98 g
c) 41 g
What is the mol fraction NaNO3 in a solution which is
2.15 m?
a) 0.0180
d) 0.09387
b) 0.0268
e) 0.0785
A student prepared a solution containing 0.30 mol
solute and 1.00 mole solvent. The mole fraction of
solvent is
c) 0.0373
5.
9.
a) 1.30
d) 0.30
A 1.34 M NiCl2 (molar mass = 129.6 g/mol) solution
b) 1.00
e) 0.23
has a density of 1.12 g/cm3. What is the weight
c) 0.77
percent NiCl2 of the solution?
a) 1.73%
d) 25.4%
b) 8.64%
e) 29.8%
c) 15.5%
10. Which measure of concentration is most appropriate
15. What is the primary energetic factor in the lack of
for the calculation of the vapor pressure of a solution?
miscibility between CCl4(l) and water?
a) mol fraction
d) weight %
a) the strength of intermolecular forces between CCl4
b) molarity
e) ppm
c) molality
molecules
b) the strength of intermolecular forces between H2O
molecules
11. A chemist knows the empirical formula of a new
compound but not the molecular formula. What must
be determined experimentally so that the molecular
formula can be determined?
a) density
d) melting point
b) viscosity
e) molar mass
c) % composition
c) the charge on the C atom in CCl4
d) the difference between the molecular weights of
the molecules
e) the electronegativity difference between carbon
and chlorine
16. Which of the following would have a boiling point
closes to that of 1 m NaCl?
12. A volumetric flask is necessary for the preparation of
a) 1 m sucrose (C12H22O11)
which one of the following concentration
b) pure H2O
d) 0.5 m CH3OH
measurements?
c) 1 m MgCl2
e) 1 m NH4NO3
a) molality
d) molarity
b) X
e) ppm
c) mass %
17. Which of the following would have the highest
freezing point?
a) 1 m glucose (C6H12O6)
13. If the pressure of a gas over a liquid increases, the
amount of gas dissolved in the liquid will
b) 1 m MgCl2
d) 1 m (NH4)2SO4
c) 1 m NaNO3
e) pure H2O
a) increase
b) decrease
18. You need a solution that is 0.15 m in ions. How many
c) remain the same
grams of MgCl2 (molar mass = 95.2 g/mol) must you
d) have a higher vapor pressure
dissolve in 400. g of water? (Assume total dissociation
e) depends on the polarity of the gas
of the ionic salt.)
14. Which of the following solutions would have the
lowest vapor pressure?
a) 0.060 g
d) 7.6 g
b) 1.9 g
e) 17 g
c) 5.7 g
a) 1 m glucose (C6H12O6)
b) 1 m MgCl2
d) 1 m NaBr
c) 1 m NaNO3
e) pure H2O
19. A solution is prepared by dissolving 0.500 g of non-
22. Concentrated salt solutions have boiling points lower
dissociating solute in 12.0 g of cyclohexane. The
than those calculated using the equation,
freezing point depression of the solution is 8.94C.
Tb = Kb · m.· i Which of the following is a reasonable
The Kfp for cyclohexane is -20.0C/m. Calculate the
explanation of this observation?
molar mass of the solute.
a) Positive ions repel each other more at high
a) 93.2 g/mol
d) 182 g/mol
b) 112 g/mol
e) 205 g/mol
concentration.
b) Ions of opposite charge will tend to stay paired
c) 128 g/mol
instead of breaking up.
c) The water molecules will have a greater attraction
20. What is the freezing point of a solution containing
4.134 grams naphthalene (molar mass = 128.2)
for each other.
d) Concentrated solutions really have small particles
dissolved in 30.0 grams paradichlorobenzene? The
freezing point of pure paradichlorobenzene is 53.0C
of non-dissolved salt, thus lowering the molality.
e) The difference between the crystal lattice energy
and the freezing point depressing constant Kfp is -
and the heat of hydration must be taken into
7.10C/m.
consideration.
a) 52.0C
d) 17.6C
b) 48.7C
e) 7.63C
c) 45.4C
Answers:
21. What is the molar mass of a compound if 4.28 grams is
1.
A
11.
E
dissolved in 25.0 grams of chloroform solvent to form
2.
A
12.
D
a solution which has a boiling point elevation of
3.
E
13.
A
2.30C. The boiling point constant of chloroform Kbp
4.
C
14.
B
is +3.63C/m.
5.
C
15.
B
6.
E
16.
E
7.
C
17.
E
8.
E
18.
B
9.
C
19.
A
10.
A
20.
C
21.
E
22.
B
a) 34.5 g/mol
d) 168 g/mol
b) 67.5 g/mol
e) 270 g/mol
c) 135 g/mol