Name
No:
Homework 3
1- Which of the following gives the molarity of a 17.0% by mass solution of sodium
acetate, CH3COONa (molar mass = 82.0 g/mol) in water? The density of the
solution is 1.09 g/mL.
A. 2.26  10-6 M
B. 0.207 M
C. 2.07 M
D. 2.26 M
E. 2.72 M
2- What is the molarity of a solution that is 26.0% by mass phosphoric acid (H3PO4)
and that has a density of 1.155 g/mL?
A. 2.30  10-3 M
B. 0.30 M
C. 2.30 M
D. 3.06 M
E. 300 M
3- What is the percent CdSO4 by mass in a 1.0 molal aqueous CdSO4 solution?
A. 0.001 %
B. 0.10 %
C. 17.2 %
D. 20.8 %
E. 24.4 %
4- What is the percent CsCl by mass in a 0.711 M CsCl solution that has a density of
1.091 g/mL?
A. 3.87  10-4 %
B. 3.87  10-1 %
C. 11.0 %
D. 1.1 %
E. 6.5  10-2 %
5- How many grams of water are needed to dissolve 27.8 g of ammonium nitrate
NH4NO3 in order to prepare a 0.452 m solution?
A. 769 g
B. 36.2 g
C. 100. g
D. 0.157 g
E. 157 g
6- The solubility of gases in water usually decreases with
A.
B.
C.
increasing pressure.
increasing temperature.
decreasing temperature.
1
Name
No:
Homework 3
7- The vapor pressure of water at 20C is 17.5 mmHg. What is the vapor pressure of
water over a solution prepared from 2.00  102 g of sucrose (C12H22O11) and
3.50  102 g water?
A. 0.51 mmHg
B. 16.0 mmHg
C. 17.0 mmHg
D. 18.0 mmHg
E. 19.4 mmHg
8- A solution is 40.0% by volume benzene (C6H6) in carbon tetrachloride at 20C.
The vapor pressure of pure benzene at this temperature is 74.61 mmHg and its
density is 0.87865 g/cm3; the vapor pressure of pure carbon tetrachloride is
91.32 mmHg and its density is 1.5940 g/cm3. If this solution is ideal, its total
vapor pressure at 20C is
A. 84.64 mmHg.
B. 84.30 mmHg.
C. 82.96 mmHg.
D. 81.63 mmHg.
E. 165.93 mmHg.
9- Dissolving a solute such as KOH in a solvent such as water results in
A. an increase in the melting point of the liquid.
B. a decrease in the boiling point of the liquid.
C. a decrease in the vapor pressure of the liquid.
D. no change in the boiling point of the liquid.
10- What is the freezing point of a solution that contains 10.0 g of glucose (C6H12O6)
in 100. g of H2O? Kf for water is 1.86C/m.
A.
B.
C.
D.
E.
-0.186C
+0.186C
-0.10C
+0.10C
-1.03C
11. Which of the following aqueous solutions has the highest boiling point?
Kb for water is 0.52C/m.
A.
B.
C.
D.
E.
0.2 m KCl
0.2 m Na2SO4
0.2 m Ca(NO3)2
0.2 m KCl AND 0.2 m Na2SO4
0.2 m Na2SO4 AND 0.2 m Ca(NO3)2
2