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___ 19. Which of the following solutions would not
be
expected to exist?
|
a) |
NaCl in water |
|
b) |
Pentane, C5H12,
in CCl4 |
|
c) |
Methyl
alcohol, CH3OH, in water |
|
d) |
Vegetable oil
in mineral oil |
|
e) |
NaCl in CCl4 |
___
20. Which one of the following
statements is false?
|
a) |
The solvation
process usually absorbs heat. |
|
b) |
Nonpolar
solids do not dissolve appreciably in polar solvents. |
|
c) |
The solubility
of a gas that does not react with the solvent decreases as
temperature increases. |
|
d) |
The separation
of solute particles from a crystal requires energy. |
|
e) |
The effects of
lattice energies and hydration energies Oppose each
other in the dissolution of solids in liquids. |
___ 21. The dissolution process is exothermic if the
amount of energy released in bringing about a interactions exceeds
the sum of the amounts of energy absorbed in overcoming b and c interactions.
|
a |
b |
c |
|
a) |
solvent-solvent solute-solute solvent-solute |
|
b) |
solvent-solute solute-solute crystal
lattice |
|
c) |
solute-solute crystal
lattice solvent-solvent |
|
d) |
solvent-solute solute-solute solvent-solvent |
|
e) |
solute-solute solvent-solvent solvent-solute |
___
22. What is the molality of an aqueous
solution that is 10.0% ethanol, C2H5OH, by mass?
|
a) |
1.77 m |
|
b) |
2.17 m |
|
c) |
2.42 m |
|
d) |
2.66 m |
|
e) |
1.38 m |
___
23. . What is the mass % solute of a 2.00
molal H2SO4 solution in water?
|
a) |
9.8 % |
|
b) |
19.6 % |
|
c) |
2.0 % |
|
d) |
16.4 % |
|
e) |
1.1 % |
___ 24. The solubility of
nitrogen (N2) in blood at 0.78 atm
and 37oC (physiological conditions on land) is 1.65 mg/L. What would be the concentration of N2 in the blood at
2.50 atm (deep-sea diving conditions) at the same temperature?
|
a) |
11.8 mg/L |
|
b) |
5.29 mg/L |
|
c) |
4.12 mg/L |
|
d) |
0.515 mg/L |
|
e) |
Not enough
information To determine |
___ 25. For salts which are more soluble in cold
water than in hot water…
|
a) |
the lattice
energy is greater than the hydration energy |
|
b) |
the heat of
solution is positive |
|
c) |
the
dissolution process is endothermic |
|
d) |
the hydration
process is endothermic |
|
e) |
the hydration
energy is greater than the lattice
energy |
___ 26. A solution contains 10.0 g pentane, C5H12,
10.0 g hexane, C6H14 and 10.0 g benzene, C6H6.
What is the mole fraction of hexane?
|
a) |
0.116 |
|
b) |
0.333 |
|
c) |
0.362 |
|
d) |
0.335 |
|
e) |
0.303 |
___ 27. Calculate the boiling point of a solution
prepared by dissolving 70.0 g of naphthalene, C10H8 (a
nonvolatile nonelectrolyte), in 220.0 g of benzene, C6H6.
The Kb for benzene = 2.53oC/m. The boiling
point of pure benzene is 80.1oC.
|
a) |
73.8oC |
|
b) |
83.2oC |
|
c) |
86.4oC |
|
d) |
106.3oC |
|
e) |
87.8oC |
___ 28. What is the vapor pressure of a aqueous
solution containing 10 %(by weight) ethylene glycol (62 g/mol) at 25 oC.
PH2O= 24.3 torr at 25 oC.
|
a) |
21.9 torr |
|
b) |
23.5 torr |
|
c) |
18.9 torr |
|
d) |
0.761 torr |
|
e) |
25.1 torr |
___ 29. A colloid can be easily distinguished from a
“true solution” because a colloidal
dispersion….
|
a) |
tends to
exhibit a lower boiling point than the pure solvent |
|
b) |
will scatter
light, producing a non-transparent medium |
|
c) |
will be
repelled by an electric field |
|
d) |
will form even
if DHsoln is endothermic |
|
e) |
is transparent |
___ 30. Which of the following statements regarding
a 1 M sucrose solution is not correct?
|
a) |
The freezing
point is less than that of a 1 M NaCl solution. |
|
b) |
The freezing
point is less than 0.0oC. |
|
c) |
The boiling
point is less than that of a 1 M NaCl solution. |
|
d) |
The vapor
pressure at 100oC is less than 760 torr. |
|
e) |
The boiling
point is greater than 100oC. |
___ 31. Iodine (I2) is more soluble in
carbon tetrachloride (CCl4) than water because…
|
a) |
iodine and CCl4
are both nonpolar while water is polar |
|
b) |
iodine and
water exhibit similar intermolecular attractions |
|
c) |
both iodine and
CCl4 contain halogens |
|
d) |
iodine and CCl4
are both polar while water is
nonpolar |
|
e) |
iodine and CCl4
possess similar molecular weights |
___ 32. What is the molecular weight of a polymer if
1.55 g of it dissolved in 100 mL of water generates osmotic pressure equal to
15.2 torr at 25oC?
|
a) |
24.3 g/mol |
|
b) |
624 g/mol |
|
c) |
19.0 g/mol |
|
d) |
19,000 g/mol |
|
e) |
24,100 g/mol |
___ 33. The freezing point of an aqueous solution
containing 15 g of a nonelectrolyte in 150 mL water is -5.4oC. What
is the molecular weight of the compound ?
Kf = 1.86oC/m for water.
|
a) |
2.78 g/mol |
|
b) |
34.4 g/mol |
|
c) |
41.2 g/mol |
|
d) |
53.8 g/mol |
|
e) |
121 g/mol |
CHEM 1120-002
Quiz 2 Keys
(See Form A to correlate with questions on other forms.)
|
|
Test Form |
|
|
Question # |
A
|
B |
|
19 |
e |
e |
|
20 |
a |
a |
|
21 |
d |
b |
|
22 |
c |
c |
|
23 |
d |
d |
|
24 |
b |
e |
|
25 |
e |
a |
|
26 |
e |
a |
|
27 |
c |
c |
|
28 |
b |
d |
|
29 |
b |
b |
|
30 |
a |
c |
|
31 |
a |
e |
|
32 |
d |
a |
|
33 |
b |
b |