Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
| 1. | What
is the definition of molality? a. | moles of solute per liter of solution | b. | grams of solute
per kg of solution | c. | milligrams of solute per liter of
solution | d. | moles of solute per liter of solvent | e. | moles of solute
per kg of solvent | | |
|
|
| 2. | The
weight percent of concentrated H2SO4 is 96.0% and its density is 1.84 g/mL.
What is the molarity of concentrated H2SO4? a. | 9.79
M | b. | 12.0
M | c. | 18.0
M | d. | 53.2
M | e. | 245
M | | |
|
|
| 3. | 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 | | |
|
|
| 4. | If
the concentration of potassium chloride in water is 113 ppm, what is the molarity of potassium
chloride in water? The molar mass of KCl is 74.55 g/mol. Assume the density of the solution is 1.00
g/mL. a. | 1.52
´ 10-9
M | b. | 1.19
´ 10-4
M | c. | 1.52
´ 10-3
M | d. | 8.42
´ 10-3
M | e. | 0.660
M | | |
|
|
| 5. | Which
of the following statements are CORRECT?
1. | Solubility is the concentration of solute in equilibrium with
undissolved solute in a saturated solution. | 2. | If two liquids mix to an appreciable extent to form a solution,
they are immiscible. | 3. | If two liquids mix completely in any proportion to form a
solution, the resulting solution is supersaturated. | | |
a. | 1 only | b. | 2
only | c. | 3
only | d. | 1 and
2 | e. | 2 and
3 | | |
|
|
| 6. | Two
nonpolar solvents, such as hexane and carbon tetrachloride, may be miscible even though the enthalpy
of mixing of these liquids might be small. A reason that mixing occurs is that mixtures have greater
disorder than pure solvents. The tendency toward disorder is a thermodynamic function called
____. a. | entropy | b. | enthalpy | c. | saturation | d. | adhesion | e. | cohesion | | |
|
|
| 7. | Which
substance will most likely NOT quantitatively follow Henry's law when dissolved in
water?
|
|
| 8. | Which
action(s) will decrease the equilibrium concentration of a non-reacting gas in
water?
1. | decreasing the temperature of the
water | 2. | decreasing the
volume of water | 3. | decreasing the pressure of the gas above the
liquid | | |
a. | 1
only | b. | 2
only | c. | 3
only | d. | 1 and
3 | e. | 1, 2, and
3 | | |
|
|
| 9. | The
Henry's law constant for O2 in water at 25 °C is 1.66 ´ 10-6 M/mm Hg. What partial pressure of
O2 is necessary to achieve an equilibrium concentration of 0.150 M
O2? a. | 2.49
´ 10-7
mm Hg | b. | 6.23 ´ 10-6 mm Hg | c. | 1.11
´ 10-5
mm Hg | d. | 9.04 ´ 104 mm Hg | e. | 4.02
´ 106
mm Hg | | |
|
|
| 10. | Ideally, colligative properties depend only on the a. | concentration of
solute particles in a solution. | b. | identity of the solute particles in a
solution. | c. | color of a solution. | d. | hydrated radii
of the molecules or ions dissolved in a solution. | e. | partial pressure
of the gases above the surface of a solution. | | |
|
|
| 11. | What
is the equilibrium partial pressure of water vapor above a mixture of 24.0 g H2O and 48.0
g CH3CH2OH at 25 °C. The partial pressure of pure water at 25.0 °C is 23.8 mm Hg.
Assume ideal behavior for the solution. a. | 0.561 mm Hg | b. | 7.93 mm
Hg | c. | 10.4 mm
Hg | d. | 11.9 mm
Hg | e. | 13.4 mm
Hg | | |
|
|
| 12. | 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 | | |
|
|
| 13. | 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 | | |
|
|
| 14. | 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 | | |
|
|
| 15. | What
is the freezing point of a solution containing 4.78 grams naphthalene (molar mass = 128.2 g/mol)
dissolved in 32.0 grams paradichlorobenzene? The freezing point of pure paradichlorobenzene is 53.0
°C and the
freezing point depression constant, Kfp, is -7.10 °C/m. a. | -1.63 °C | b. | 44.7 °C | c. | 46.9 °C | d. | 51.9 °C | e. | 52.1 °C | | |
|
|
| 16. | 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 | | |
|
|
| 17. | A
0.561 m solution of an unknown electrolyte depresses the freezing point of water by 2.93
°C. What is the
van't Hoff factor for this electrolyte? The freezing point depression constant,
Kfp, for water is -1.86 °C/m. a. | 0.103 | b. | 1.92 | c. | 2.81 | d. | 3.05 | e. | 3.99 | | |
|
|
| 18. | What
concentration unit is used in the calculation of osmotic pressure for a dilute
solution? a. | molality | b. | weight percent | c. | mass
fraction | d. | mole fraction | e. | molarity | | |
|
|
| 19. | A
solution is prepared by dissolving 4.78 g of an unknown nonelectrolyte in enough water to make 0.500
L of solution. The osmotic pressure of the solution is 1.98 atm at 27 °C. What is the
molar mass of the solute? (R = 0.08206 L·atm/mol·K) a. | 24.9
g/mol | b. | 59.4 g/mol | c. | 119
g/mol | d. | 233 g/mol | e. | 466
g/mol | | |
|
|
| 20. | All
of the following are colloidal dispersions EXCEPT a. | ice cubes. | b. | cheese. | c. | butter. | d. | clouds. | e. | shaving cream. | | |
|