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Solutions
Copyright
D. Herrick |
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20 Questions from past exams.
Practice for speed. Aim
for 2 minutes per problem.
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Constants:
Gas constant: R = 0.08206 L-atm/mol-K = 8.314 J/mol-K
properties of
water
density = 1.0 g/mL
Kb = 0.52°C/m
Kf = 1.86°C/m
freezing point = 0.00°C
boiling point =
100.00°C |
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| 1. |
What
is the strongest type of intermolecular force between
solute and solvent in an aqueous solution of KCl? |
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| A) |
hydrogen
bonding |
| B) |
dipole-dipole |
| C) |
ion-dipole |
| D) |
ion-induced
dipole |
| E) |
dipole-induced
dipole |
| F) |
dispersion |
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| 2. |
What
is the strongest type of intermolecular force between
solute and solvent in a solution of Br2
in CCl4? |
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| A) |
hydrogen
bonding |
| B) |
dipole-dipole |
| C) |
ion-dipole |
| D) |
ion-induced
dipole |
| E) |
dipole-induced
dipole |
| F) |
dispersion |
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| 3. |
What
is the strongest type of intermolecular force between
solute and solvent in a solution of CH3NH2
in hexane (C6H14)? |
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| A) |
hydrogen
bonding |
| B) |
dipole-dipole |
| C) |
ion-dipole |
| D) |
ion-induced
dipole |
| E) |
dipole-induced
dipole |
| F) |
dispersion |
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| 4. |
What
is the strongest type of intermolecular force between
solute and solvent in a solution of CH3NH2
in NH3? |
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| A) |
hydrogen
bonding |
| B) |
dipole-dipole |
| C) |
ion-dipole |
| D) |
ion-induced
dipole |
| E) |
dipole-induced
dipole |
| F) |
dispersion |
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| 5. |
Diethyl
ether has a vapor pressure of 400.0 torr at 18°C .
When a sample of a nonvolatile molecular solid is
dissolved in ether, the vapor pressure of the solution
is 192 torr. What is the mole fraction of the
solute in the solution? |
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| A)
0.73 |
B)
0.48 |
C)
0.50 |
D)
0.52 |
E)
0.36 |
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| 6. |
Which
aqueous solution has the highest number of moles of
solute particles in 1.00 L of solution? |
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| A) |
0.19
M CaCl2 |
| B) |
0.14
M FeCl3 |
| C) |
0.27
M KCl |
| D) |
0.55
M ethanol (CH3CH2OH) |
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| 7. |
The
freezing point of benzene is 5.5°C. What is the freezing point of a solution of 2.46
g of naphthalene (C10H8,
MW = 128.2) in 512 g of benzene (Kf of
benzene = 4.90°C/m)?
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| A)
5.7°C |
B)
5.3°C |
C)
5.9°C |
D)
5.1°C |
E)
4.9°C |
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| 8. |
Which
aqueous solution has the lowest boiling point? |
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| A) |
0.19
m CaCl2 |
| B) |
0.14
m FeCl3 |
| C) |
0.27
m KCl |
| D) |
0.55
m ethanol (CH3CH2OH) |
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| 9. |
Human
blood has a molar concentration of solute particles of
0.30 M. What is the osmotic pressure (in atm) of
blood at 37°C? |
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| A)
8.0 |
B)
7.3 |
C)
6.9 |
D)
7.0 |
E)
7.6
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| 10. |
Gases
like oxygen that are weakly soluble in water tend to be
more soluble under conditions of |
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| A) |
low
pressure and low temperature |
| B) |
low
pressure and high temperature |
| C) |
high
pressure and low temperature |
| D) |
high
pressure and high temperature |
| E) |
solubility
is independent of pressure and temperature |
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| 11. |
Calculate
the vapor pressure (torr) of a solution of benzene and
toluene in which the mole fraction of toluene is
0.35. The vapor pressure of pure benzene at the
temperature of the solution is 75 torr; the vapor
pressure of pure toluene is 22 torr. |
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| A)
39 |
B)
56 |
C)
81 |
D)
27 |
E)
45 |
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| 12. |
A
solution is 15% glucose (MW = 180) and 85% water (MW =
18) by mass. The density of the solution is 1.2 g/mL.
The molality of glucose in the solution is |
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| A)
0.29 |
B)
0.84 |
C)
0.15 |
D)
1.20 |
E)
0.98 |
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| 13. |
An
aqueous solution containing an unknown nonelectrolye
solute freezes at -5.37°C; the molality of the solute
in this solution is
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| A)
10.33 |
B)
5.16 |
C)
1.05 |
D)
2.89 |
E)
3.65 |
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| 14. |
Potassium
salts are strongly ionized when they dissolve in
water. Calculate the boiling point of a solution
that contains 2.0 mol of K3PO4
dissolved in 500 g of water. |
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| A) |
108.3°C |
| B) |
103.5°C |
| C) |
105.7°C |
| D) |
-94.0°C |
| E) |
106.4°C |
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| 15. |
An
"antifreeze" aqueous solution of ethylene
glycol has a freezing point of -10.0°C; estimate the
boiling point of the same solution. |
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| A) |
97.4°C |
D) |
103.5°C |
| B) |
100.1°C |
E) |
108.3°C |
| C) |
106.4°C |
F) |
102.8°C
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| 16. |
If
C is the molar concentration of a protein in a water
solution, the expression for the osmotic pressure of the
solution is |
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| A) |
RT/C |
D) |
RTC |
| B) |
CT/R |
E) |
T/RC |
| C) |
RC/T |
F) |
C/RT |
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| 17. |
When
1.0 g of glucose (MW = 180) is dissolved in water the
osmotic pressure of the solution is 100 torr. When
3.0 g of an unknown protein is dissolved in the same
amount of water the osmotic pressure is 4.2 torr.
Estimate the molecular weight of the protein. |
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| A) |
12,900 |
D) |
14,200 |
| B) |
10,300 |
E) |
28,400 |
| C) |
6,800 |
F) |
19,600 |
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| 18. |
Which
of the following is NOT a colligative property? |
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| A) |
freezing
point lowering |
| B) |
osmotic
pressure |
| C) |
expansion
on freezing |
| D) |
boiling
point elevation |
| E) |
vapor
pressure lowering |
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| 19. |
Predict
the alcohol with the lowest solubility in water: |
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| A) |
CH3OH |
| B) |
CH3CH2OH |
| C) |
CH3CH2CH2OH |
| D) |
CH3CH2CH2CH2CH2CH2OH |
| E) |
HOCH2CH2OH |
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| 20. |
Which
soluble ionic salt is expected to have the largest (most
negative) heat of hydration? |
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| A) |
KCl |
| B) |
LiF |
| C) |
NaBr |
| D) |
CsI |
| E) |
RbCl |
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