Name:    Colligative Properties

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

1.

To prepare 1.000 kg of 5.5% by mass KCl(aq), one may dissolve
 a. 994.5 g KCl in 5.5 g of water. b. 5.5 g KCl in 994.5 g of water. c. 5.5 g KCl in 1000.0 g of water. d. 55 g KCl in 945 g of water. e. 55.0 g KCl in 1000.0 g of water.

2.

What is the molality of 13.82% by mass sulfuric acid? The molar mass of H2SO4 is 98.08 g/mol.
 a. 0.1409 m b. 1.409 m c. 1.635 m d. 13.55 m e. 15.73 m

3.

What is the weight percent of ammonia in 3.33 m NH3(aq)?
 a. 0.332% b. 5.37% c. 5.67% d. 6.01% e. 56.7%

4.

A solution is prepared by mixing 66.7 g H2O with 33.3 g HOCH2CH2OH (ethylene glycol). What is the concentration of ethylene glycol in units of molality? The molar masses of water and ethylene glycol are 18.02 g/mol and 62.07 g/mol, respectively.
 a. 0.127 m b. 0.333 m c. 4.99 m d. 5.36 m e. 8.04 m

5.

Which of the following aqueous solutions should have the lowest freezing point?
 a. pure H2O b. 1 m NaBr c. 1 m Ca(NO3)2 d. 1 m NH3 e. 1 m C6H12O6

6.

Which of the following aqueous solutions should have the lowest boiling point?
 a. 0.50 m KCl b. 0.50 m Na2SO4 c. 0.50 m CaBr2 d. 1.5 m KI e. 2.0 m C6H12O6

7.

The freezing point depression constant for water is -1.86 °C/m. At what temperature will a solution containing 7.99 g BaCl2 and 52.0 g H2O begin to freeze? Assume that no ion-pairing occurs between Ba2+ and Cl-.
 a. -4.12 °C b. -2.75 °C c. -1.37 °C d. -0.857 °C e. -0.248 °C

8.

What is the molar mass of a nonpolar molecular compound if 5.52 grams dissolved in 36.0 grams of benzene begins to freeze at -1.87 °C? The freezing point of pure benzene is 5.50 °C and the freezing point depression constant, Kfp, is -5.12 °C/m.
 a. 46.1 g/mol b. 107 g/mol c. 216 g/mol d. 221 g/mol e. 419 g/mol

9.

What is the boiling point of a solution containing 2.33 g of caffeine, C8H10N4O2, dissolved in 15.0 g of benzene? The boiling point of pure benzene is 80.1 °C and the boiling point elevation constant, Kbp, is 2.53 °C/m.
 a. 2.02 °C b. 78.1 °C c. 80.2 °C d. 82.1 °C e. 83.3 °C

10.

What is the change in the freezing point of a solution made by dissolving 14.7 g of C6H12O6 into 150.0 mL of water? The density of water is 1.00 g/mL and Kf = 1.86°C/m.
 a. 0.152 °C b. 1.01 °C c. 18.9 °C d. 1.82 °C e. none of the above

11.

Given that the solubility of sodium acetate (Molar mass = 82 g/mol) is 76 grams per 100 grams of water. Which of the following solutions would be considered supersaturated?
 a. 8.5 moles of sodium acetate dissolved in 1 L of water b. 5.5 moles of sodium acetate dissolved in 500 mL of water c. 1.8 moles of sodium acetate dissolved in 300 mL of water d. 1.2 moles of sodium acetate dissolved in 200 mL of water e. None of the above

12.

Given that the solubility of sodium chloride is 36 grams per 100 grams of water. Which of the following solutions would be considered unsaturated?
 a. dissolve 5.80 moles of NaCl in 1 L of water b. dissolve 3.25 moles of NaCl in 500 ml of water c. dissolve 1.85 moles of NaCl in 300 ml of water d. dissolve 4.95 moles of NaCl in 750 mL of water e. none of the above

13.

When an ionic compound dissolves in water
 a. the solvent-solute attractive forces overcome the solute-solute attractions. b. the positive end of water dipoles attract the negative ions. c. the negative end of water dipoles attract the positive ions d. each of the above (A, B, and C) occurs. e. none of the above (A, B, or C) occurs.

14.

The solubility of a gas in a liquid can always be increased by
 a. increasing the temperature of the solvent. b. decreasing the polarity of the solvent. c. decreasing the pressure of the gas above the solvent. d. increasing the pressure of the gas above the solvent. e. none of the above

15.

When preparing sodium hydroxide solution, it is best to use water that does not contain any dissolved carbon dioxide as it reacts with the sodium hydroxide. Removing the carbon dioxide can be accomplished by:
 a. vigorously stirring the solution. b. using water fresh out of the purification system. c. boiling the water. d. Nothing can be done to remove dissolved gases. e. none of the above

16.

A solution contains 100.0 g water, 10.0 g NaCl, and 15.0 g methanol. What is the weight percent of methanol in the solution?
 a. 8.00% b. 10.0%. c. 12.0% d. 15.0% e. none of the above

17.

What is the mass percent of a solution prepared by dissolving 18.9 grams of solid into 39.5 grams of water?
 a. 47.8% b. 58.4% c. 32.4% d. The identity of the compound must be known. e. none of the above

18.

What is the molality of a solution made by dissolving 14.7 g of C6H12O6 into 150.0 mL of water? Assume the density of water is 1.00 g/mL.
 a. 0.544 m b. 0.0816 m c. 10.2 m d. 0.980 m e. none of the above

19.

Why is not a good idea to drink seawater when people are lost at sea?
 a. The high concentration of salt forces water out of the cells lining your stomach and intestine. b. The osmotic pressure builds up in the cells of your intestine until they potentially rupture. c. The semipermeable membrane protecting your stomach is ruptured during osmosis. d. The seawater has fish crap in it and who wants to drink that? e. none of the above

20.

Solution A has a concentration of 0.10 M sugar and Solution B has a concentration of 0.20 M sugar. If the two solutions are separated by a semipermeable membrane, which of the following occurs during osmosis?
 a. Solvent molecules move from B into A. b. Sugar molecules move from B into A. c. The molarity of A increases. d. The molarity of B increases. e. none of the above