Assignment 2 (A)
CHAPTER 13
PHYSICAL PROPERTIES OF SOLUTIONS
1- Which of the following liquids would make a good solvent for iodine, I 2?
A. HCl
B. H2O C. CH3OH D. NH3
E. CS2
2- Which of the following compounds will be soluble in CCl4?
A. NaCl
B. H2O
C. NaOH
D. C8H18
E. none of these
3- Which of the following gives the molarity of a 17.0 % solution of sodium acetate, CH 3COONa (FM = 82.0 amu) in
water? Given the density 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
4- What is the percent CdSO4 by mass in a 1.0 molal aqueous solution (molar mass of CdSO 4 = 208.46 g/mol)?
A. 0.001 % B. 0.10 % C. 17.2 % D. 20.8 % E. 24.4 %
5- How many grams of water are needed to dissolve 27.8 g of ammonium nitrate NH 4NO3 in order to prepare a 0.452 m
solution?
A. 0.157 g B. 36.2 g C. 100 g D. 769 g E. 157 g
6- Calculate the molality of a 20.0 % by mass ammonium sulfate (NH 4)2SO4 solution. The density is 1.117 g/mL.
A. 0.15 m B. 1.51 m C. 1.70 m D. 1.89 m E. 2.10 m
7- The density of a 20.3 M CH3OH (methanol) solution is 0.858 g/mL. What is the molality of this solution? H 2O is
the solvent.
A. 17.4 m B. 20.8 m C. 23.7 m D. 70.0 m E. 97.5 m
8- The solubility of gases in water usually decreases with:
A. increased pressure
B. increased temperature
C. decreased temperature
9- The solubility of CO2 gas in water:
A. increases with increasing gas pressure.
B. increases with decreasing gas pressure.
C. decreases with increasing gas pressure.
D. is not dependent on pressure.
10- The vapor pressure of water at 20oC 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 mm Hg
B. 16.0 mm Hg
C. 17.0 mm Hg
D. 18.0 mm Hg
E. 19.4 mm Hg
11- What is the freezing point of a solution that contains 10.0 g of glucose (C 6H12O6) in 100 g of H2O?
A. ─0.186oC
B. +0.186oC
C. ─0.10oC
D. +0.10oC
E. ─1.03oC
Kf = 1.86oC/m.
12- Which of the following aqueous solutions has the highest boiling point? Given K b = 0.52oC/m.
A. 0.2 m KCl
B. 0.2 m Na2SO4
C. 0.2 m Ca(NO3)2
D. pure water
E. more than one of the above
13- Calculate the freezing point of a solution made from 22.0 g of octane (C8H18) dissolved in 148.0 g of benzene.
Benzene freezes at 5.50oC and its Kf is 5.12oC/m.
A. ─1.16oC
B. 0.98oC
C. 6.66oC
D. 12.2oC
E. 5.49oC
14- A solution that contains 55.0 g of ascorbic acid (Vitamin C) in 250 g of water freezes at ─2.34 oC. Calculate the
molar mass (g/mol) of the solute. Kf = 1.86oC/m.
A. 1.26
B. 10.9
C. 43.6
D. 175
E. 277
15- What mass of ethanol, C2H5OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at
─10.0oC? Assume the density of water is 1.0 g/mL. Kf = 1.86 oC/m
A. 85.7 kg
B. 24.8 kg
C. 5.38 kg
D. 2.48 kg
E. 1.17 kg
16- When 24.0 g of glucose (a nonelectrolyte) are dissolved in 500 g of water, the solution has a freezing point of
─0.47oC. What is the molar mass of glucose according to the data?
Kf = 1.86oC/m.
A. 41.9 g/mol
B. 47.5 g/mol
C. 54.9 g/mol D. 178 g/mol
E. 190 g/mol
17- What is the freezing point of an aqueous solution of a nonvolatile solute that has a boiling point of 102.5 oC? For
water Kf = 1.86oC/m and Kb = 0.52oC/m.
A. ─8.94oC
B. ─366oC
C. ─0.99oC
D. 0.99oC
E. 8.94oC
18- 0.102 g of an unknown compound dissolved in 100 mL of water has an osmotic pressure of 28.1 mmHg at 20 oC.
Calculate the molar mass of the compound.
A. 663 g/mol
B. 0.872 g/mol
C. 1.15 g/mol
D. 727 g/mol
E. 1.10  102 g/mol
19- Calculate the approximate freezing point of a solution made from 21.0 g NaCl and 1.00  102 g of H2O.
Kf = 1.86oC/m.
A. 3.59oC
B. 6.68oC
C. ─13.4oC
D. ─6.68oC
E. ─3.59oC
20- Which of the following aqueous solutions has the lowest freezing point?
Given K = 1.86oC/m.
A. 0.18 m KCl
B. 0.15 m Na2SO4
C. 0.12 m Ca(NO3)2
D. pure water
E. 0.20 m C2H6O2 (ethylene glycol)
21- Arrange the following aqueous solutions in order of increasing boiling points:
0.050 m Mg(NO3)2; 0.100 m ethanol; 0.090 m NaCl.
A. Mg(NO3)2 < NaCl < ethanol
B. ethanol < Mg(NO3)2 < NaCl
C. ethanol < NaCl < Mg(NO3)2
D. NaCl < ethanol < Mg(NO3)2
E. Mg(NO3)2 < ethanol < NaCl
22- The osmotic pressure of a 0.010 M MgSO4 solution at 25oC is 0.318 atm. Calculate i, the van't Hoff factor for
MgSO4.
A. 0.013
B. 1.3
C. 1.5
D. 2.0
E. 76.8
23- A solution of a non-electrolyte, X, contains 84 g per kg of water and freezes at –1.46 °C. What is the molar mass of
X? Kf for water = 1.86 °C/m
C. A. 228 g/mol
B. 107 g/mol
C. 66 g/mol
D. 0.32 g/mol
24- When one mole of naphthalene is dissolved in 1000 g of benzene, the freezing point changes from 5.51 °C to 0.41
°C. When 20 g of an unknown organic compound is dissolved in 500 g of benzene, the freezing point of this
solution is 5.00 °C. What is the molar mass of the unknown organic compound?
A. 40 g/mol
B. 200 g/mol
C. 100 g/mol
D. 400 g/mol
E. 128 g/mol
25- TRUE-FALSE QUESTIONS:
1- For dilute aqueous solutions, the two concentration units, molarity and molality, have almost the same value. T
2- The solubility of gases in water always decreases with increasing temperature.
T
3- water Kf = 1.86oC/m. Therefore the freezing points of 1.0 M aqueous KCl and C2H5OH (ethanol) solutions are the
same. F