CHEM 1412- Home-Work 1
1.
The solubility of 1-hexanol in water is 0.60 g per 100 g of water at 25°C. What is the maximum amount of 1-hexanol
that will dissolve in 7.9 g of water at 25°C?
a)
0.60 g
b)
4.7 g
c)
0.047 g
d)
0.076 g
e)
0.00076 g
2.
The solubility of O2 in water is 0.590 g/L at an oxygen pressure of around 15.0 atm. What is the Henry's law constant
for O2 (in units of L · atm/mol)?
a)
3.93 × 10-2
b)
1.23 × 10-3
c)
8.14 × 102
d)
2.77 × 10-1
e)
None of the above are within 5% of the correct answer.
3.
A 3.140 molal solution of NaCl is prepared. How many grams of NaCl are present in a sample containing 2.963 kg of
water?
a)
930.4 g
b)
159.2 g
c)
329.8 g
d)
543.7 g
e)
none of these
4.
Which of the following is not a colligative property?
a)
freezing-point lowering
b)
boiling-point elevation
c)
solute solubility
d)
osmotic pressure
e)
vapor-pressure lowering
5.
What is the mass of H2SO4 in a 45.0-cm3 sample of concentrated sulfuric acid that has a density of 1.84 g/cm3 and
consists of 98.3% H2SO4?
a)
24.0 g
b)
4.02 g
c)
81.4 g
d)
1.81 g
e)
44.2 g
6.
A sulfuric acid solution that is 65.0% H2SO4 by mass has a density of 1.55 g/mL at 20°C. What is the mass of H 2SO4
per liter of solution?
a)
1.01 kg
b)
0.550 kg
c)
1.55 kg
d)
7.50 g
e)
65.0 g
7.
What is the mass percent of an aqueous sodium hydroxide solution in which the molarity of NaOH is 19.1 M? The
density of the solution is 1.5290 g/mL.
a)
68.9%
b)
29.2%
c)
50.0%
d)
1.74%
e)
0.0800%
8.
The volume of a 15.6% (by mass) solution is 79.2 mL. The density of the solution is 1.480 g/mL. What is the mass of
the solution?
a)
183 g
b)
53.5 g
c)
d)
e)
18.3 g
117 g
1830 g
9.
What is the molarity of a 40.0% by mass hydrochloric acid solution? The density of the solution is 1.1980 g/mL.
a)
18.3 M
b)
13.1 M
c)
0.0479 M
d)
0.400 M
e)
13.9 M
10.
What mass of a 33.0% by mass glucose, C6H12O6, solution contains 54.0 g of glucose?
a)
17.8 g
b)
54.0 g
c)
59.4 g
d)
99.0 g
e)
164 g
11.
How many moles of urea (60. g/mol) must be dissolved in 71.6 g of water to give a 2.4 m solution?
a)
8.4 × 102 mol
b)
1.4 × 102 mol
c)
2.4 mol
d)
0.17 mol
e)
0.0024 mol
12.
What is the mole fraction of urea, CH4N2O, in an aqueous solution that is 46% urea by mass?
a)
0.20
b)
0.80
c)
0.45
d)
0.74
e)
0.46
13.
What is the vapor pressure at 20°C of an ideal solution prepared by the addition of 2.19 g of the nonvolatile solute
urea, CO(NH2)2, to 43.5 g of methanol, CH3OH? The vapor pressure of pure methanol at 20°C is 89.0 mmHg.
a)
2.33 mmHg
b)
84.7 mmHg
c)
81.3 mmHg
d)
7.68 mmHg
e)
86.7 mmHg
14.
What is the freezing point of a 0.19 m solution of glucose, C6H12O6, in water? (Kf for water is 1.858°C/m.)
a)
0.35°C
b)
0.18°C
c)
–0.18°C
d)
–0.35°C
e)
–0.71°C
15.
What is the boiling-point change for a solution containing 0.347 mol of naphthalene (a nonvolatile, nonionizing
compound) in 250. g of liquid benzene? (Kb = 2.53°C/m for benzene)
a)
3.51 °C
b)
1.82 °C
c)
7.29 °C
d)
0.878 °C
e)
0.219 °C
16.
When a 41.7-g sample of an unknown compound is dissolved in 500. g of benzene, the freezing point of the resulting
solution is 3.77°C. The freezing point of pure benzene is 5.48°C, and Kf for benzene is 5.12°C/m. Calculate the molar
mass of the unknown compound.
a)
124.9 g/mol
b)
24.4 g/mol
c)
214 g/mol
d)
499 g/mol
e)
250. g/mol
17.
Determine the osmotic pressure of a solution that contains 0.042 g of a hydrocarbon solute (molar mass = 340 g/mol)
dissolved in benzene to make a 350-mL solution. The temperature is 20.0°C.
a)
0.44 torr
b)
2.2 torr
c)
2.9 torr
d)
6.4 torr
e)
6.0 torr
18.
A compound containing sulfur, nitrogen, and hydrogen has a composition of 86.6% sulfur, 12.6% nitrogen, and 0.91%
hydrogen by mass. A solution prepared by dissolving 2.705 g of this compound in 20.00 g of bromoform, CHBr 3,
produces a solution that freezes at –0.96°C. What is the molecular formula of the compound? (Kf for bromoform is
14.4°C/m, and pure bromoform has a freezing point of 7.8°C.)
a)
SNH
b)
S3NH
c)
S2N2H2
d)
S3N2H2
e)
S6N2H2
19.
A cucumber is placed in a concentrated salt solution. What is most likely to happen?
a)
Water will flow from the cucumber to the solution.
b)
Water will flow from the solution to the cucumber.
c)
Salt will flow into the cucumber.
d)
Salt will precipitate out.
e)
No change will occur.
20.
A 2.2-g sample of a small protein having a molecular weight of 42,000 g/mol is dissolved in 45.6 mL of water at
23°C. What is the osmotic pressure of the solution? (R = 0.0821 L · atm/(K · mol))
a)
0.028 mmHg
b)
1.6 mmHg
c)
21 mmHg
d)
27000 mmHg
e)
890 mmHg