Twenty Questions

AP AP ChemistryChemistry

Colligative Property ReviewChapter 11

Twenty Questions

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1. A solution is prepared by dissolving 85.0 grams of ammonia (NH3) in sufficient water to produce 1.00 liter of solution. This solution has a density of 0.960 g/ml.What is the percent ammonia by weight in this solution?

A) 8.50%; B) 8.85%; C) 9.71%; D) 7.83%; E) 9.29%

8.85%

2. A solution is prepared by dissolving 85.0 grams of ammonia (NH3) in sufficient water to produce 1.00 liter of solution. This solution has a density of 0.960 g/ml. W h a t is t h e m o le f r a c t io n o f a m m o n ia in t h e s o lu t io n ?

A) 0.093; B) 0.103; C) 0.086; D) 0.096; E) 0.089

A

3. A solution is prepared by dissolving 85.0 grams of ammonia (NH3) in sufficient water to produce 1.00 liter of solution. This solution has a density of 0.960 g/ml. The molality of ammonia in the solution is:

A) 5.21; B) 5.00; C) 5.71; D) 4.61; E) 4.78

A) 5.71;

4. A solution is prepared by dissolving 85.0 grams of ammonia (NH3) in sufficient water to produce 1.00 liter of solution. This solution has a density of 0.960 g/ml.What is the molarity of ammonia in the solution?

A) 5.21; B) 5.00; C) 5.71; D) 4.61; E) 4.78

B) 5.00;.

1. Which of the following is a weak electrolyte in aqueous solution?

A) ethyl alcohol; B) H2SO4; C) HCl; D) NaCl; E) HC2H3O2

E) HC2H3O2.

6. Dissolving a solute such as NaCl in a solvent at 25oC results in:

A) an increase in the kinetic energy of the solvent molecules;

B) a decrease in the kinetic energy of the solvent molecules;

C) a decrease in the boiling point of the liquid;

D) an increase in the melting point of the liquid;

E) a decrease in the vapor pressure over the solution.

E) a decrease in the vapor pressure over the solution.

7. Which of the following solutions would have the lowest freezing point?A) 0.1 m Ca(NO3) 2; B) 0.1 m KNO3; C) 0.2 m sucrose (sugar);D) 0.1 m HCl; E) 0.1 m sucrose (sugar)..

A) 0.1 m Ca(NO3) 2;

8. Which of the following nonelectrolytes would produce the solution having the lowest freezing point if 10.0 grams of the respective compounds were dissolved in 1000 grams of water?A) alcohol, C2H6O; B) glycerin, C3H8O3; C) glucose, C6H12O6;D) methanol, CH4O; E) all produce the same effect.

D) methanol, CH4O;

9. A solution made from water and a nondissociating solute contains 10.0 grams of solute X and 800 grams of water. The freezing point of the solution is -0.31oC. What is the molecular weight of X? (kf for water = 1.86oC/m)

A) 40; B) 50; C) 80; D) 75; E) 60.

D) 75

10. The following experimental data were obtained for pure solvent S and solutions of solute X (MW = 100.) in this solvent. Solute X neither associates nor dissociates in solvent S.

Experiment Grams S Grams X Freezing point, oC

I. 100.0 0.000 16.605 II. 100.0 1.000 16.200 III. 100.0 1.750 15.907 IV. 100.0 2.200 15.710 V. 100.0 4.200 14.960

11. What is the molality of X for the solution of Experiment V?A) 0.0420 m; B) 0.420 m; C) 4.20 m; D) 0.0403 m; E) 0.104 m

B) 0.420 m;.

11.The following experimental data were obtained for pure solvent S and solutions of solute X (MW = 100.) in this solvent. Solute X neither associates nor dissociates in solvent S.

Experiment Grams S Grams X Freezing point, oC

I. 100.0 0.000 16.605 II. 100.0 1.000 16.200 III. 100.0 1.750 15.907 IV. 100.0 2.200 15.710 V. 100.0 4.200 14.960For Solutions II - V, one would need to know the (__α__) in order to determine the mole fraction of X; one would need to know (__β__) in order to calculate the molarity of X.

α βA)MW of X; density of SB) MW of S; density of XC)MW of S; density of SD) MW of X; density of the solutionE) MW of S; density of the solution

E) MW of S; density of the solution

12. The following experimental data were obtained for pure solvent S and solutions of solute X (MW = 100.) in this solvent. Solute X neither associates nor dissociates in solvent S.

Experiment Grams S Grams X Freezing point, oC

I. 100.0 0.000 16.605 II. 100.0 1.000 16.200 III. 100.0 1.750 15.907 IV. 100.0 2.200 15.710 V. 100.0 4.200 14.960

From these data, what is the molal freezing point depression constant, Kf, characteristic of solvent S?

A) 1.86oC/m; B) 2.98oC/m; C) 3.73oC/m; D) 4.01oC/m; E) 5.12oC/m.

D) 4.01oC/m;.

13. Barium phosphate is insoluble in water. If equal volumes of 0.50 M Ba(ClO4)2 and 0.20 M K3PO4 are mixed, what is the concentration of Ba2+ ions in the resulting solution?

A) 0.20 M; B) 0.00 M; C) 0.37 M; D) 0.10 M; E) 0.25 M.

E) 0.1

14. Assuming that the volumes are additive, how much water would need to be added to 30.0 ml of a 12.0 M HCl solution in order to prepare a 2.0 M HCl solution?

A) 180 ml; B) 150 ml; C) 120 ml; D) 90 ml; E) 60 ml

A) 150 ml;.

15. If 28.6 grams of "washing soda", Na2CO3

.10 H2O (FW = 286) is dissolved in 130. grams of water, what is the molality of Na2CO3 in the resulting solution?A) 0.676; B) 0.220; C) 0.893; D) 0.459; E) 0.769.

E) 0.769.

16. If the dissolution of an ionic solid in water is endothermic, then it can be concluded that:

A) the solubility of the solid will decrease with increasing temperature;

B) the solubility of the solid will increase with increasing temperature;

C) the solution process releases heat;D) the solubility of the solid is

independent of temperature;E) the hydration energy exceeds the

lattice energy.

B) the solubility of the solid will increase with increasing temperature;

17. What is the osmotic pressure (in atm.) at 0.0oC of a solution containing 1.00 gram per liter of sucrose, C12H22O11?

A) 0.066; B) 0.11; C) 0.24; D) 0.29; E) 0.48.

A) 0.066;.

18. Pure cyclohexane (C6H12, FW = 84.16) freezes at 6.55oC and has a molal freezing point depression constant, Kf, of 20.0 oC/molal. A solution of a molecular unknown X, made by dissolving 5.00 grams of X in 100.0 grams of cyclohexane, has a freezing point of 3.00oC. What is the molecular weight of X?

A) 8.88; B) 153; C) 282; D) 333; E) 747.

C) 282;.

19. What is the van't Hoff factor, i, of a 0.220-molal aqueous solution of a nonvolatile, weak electrolyte if the freezing point is -0.63oC?

A) 1.22; B) 2.05; C) 1.78; D) 3.04; E) 1.54.

E) 1.54.

20. Which substance would raise the boiling point of water the LEAST?a) HClO4

b) Mg(NO3) 3

c) CaCl2

d) LiOH e) HC2H3O2.

e) HC2H3O2.