CHEM 1412 Test Review
Name: ______Date: ______
1. / In which of the following solvents would you expect KBr to be most soluble?A) / C6H14 (hexane)
B) / CH3CH2OH (ethanol)
C) / C6H6 (benzene)
D) / CCl4 (carbon tetrachloride)
E) / C6H12 (cyclohexane)
2. / A 20.0 % by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?
A) / 0.0114 M
B) / 0.0568 M
C) / 0.114 M
D) / 2.27 M
E) / 11.4 M
3. / What is the molarity of a solution of 10% by mass cadmium sulfate, CdSO4 (molar mass = 208.46 g/mol) by mass? The density of the solution is 1.10 g/mL.
A) / 0.528 M
B) / 0.436 M
C) / 0.479 M
D) / 0.048 M
E) / 22.9 M
4. / Calculate the percent by mass of potassium nitrate in a solution made from 45.0 g KNO3 and 295 mL of water. The density of water is 0.997 g/mL.
A) / 1.51 %
B) / 7.57 %
C) / 13.3 %
D) / 15.2 %
E) / None of these
5. / The solubility of gases in water usually decreases with
A) / increasing pressure.
B) / increasing temperature.
C) / decreasing temperature.
6. / Oxygen gas makes up 21 % of the atmosphere by volume. What is the solubility of O2(g) in water at 25°C if the atmospheric pressure is 741 mmHg? The Henry's law constant for oxygen gas at 25°C is 1.3 ´ 10–3 mol/L·atm.
A) / 2.7 ´ 10–4 M
B) / 1.3 ´ 10–3 M
C) / 6.2 ´ 10–3 M
D) / 9.6 ´ 10–3 M
E) / 0.96 M
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. / 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) / –0.186°C
B) / +0.186°C
C) / –0.10°C
D) / +0.10°C
E) / –1.03°C
9. / Which of the following aqueous solutions has the highest boiling point? Kb for water is 0.52°C/m.
A) / 0.2 m KCl
B) / 0.2 m Na2SO4
C) / 0.2 m Ca(NO3)2
D) / A and B.
E) / B and C.
10. / What is the osmotic pressure of a solution prepared from 13.7 g of the electrolyte HCl and enough water to make 0.500 L of solution at 18°C?
A) / 0.55 atm
B) / 1.10 atm
C) / 8.95 atm
D) / 17.9 atm
E) / 35.9 atm
11. / Chlorine dioxide reacts in basic water to form chlorite and chlorate according to the following chemical equation:
2ClO2(aq) + 2OH–(aq) ® ClO2–(aq) + ClO3–(aq) + H2O(l)
Under a certain set of conditions, the initial rate of disappearance of chlorine dioxide was determined to be 2.30 x 10–1 M/s. What is the initial rate of appearance of chlorite ion under thos same conditions?
A) / 5.75 x 10–2 M/s
B) / 1.15 x 10–1 M/s
C) / 2.30 x 10–1 M/s
D) / 4.60 x 10–1 M/s
E) / 9.20 x 10–1 M/s
12. / The reaction A + 2B ® products has been found to have the rate law, rate = k[A] [B]2. While holding the concentration of A constant, the concentration of B is increased from x to 3x. Predict by what factor the rate of reaction increases.
A) / 3
B) / 6
C) / 9
D) / 27
E) / 30
13. / Use the following data to determine the rate law for the reaction shown below.
2NO + H2 ® N2O + H2O
Expt. # / [NO]0 / [H2]0 / Initial rate
1 / 0.
21 / 0.065 / 1.46 M/min
2 / 0.021 / 0.260 / 1.46 M/min
3 / 0.042 / 0.065 / 5.84 M/min
A) / rate = k[NO]
B) / rate = k[NO]2
C) / rate = k[NO][H2]
D) / rate = k[NO]2[H2]
E) / rate = k[NO]2[H2]2
14. / At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 ´ 10–3 min–1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25°C?
A) / 1.14 ´ 10–1 M
B) / 47.4 M
C) / –8.72.0 M
D) / 2.11 ´ 10–2 M
E) / 2.68 ´ 10–2 M
15. / The activation energy of a certain uncatalyzed reaction is 64 kJ/mol. In the presence of a catalyst, the Ea is 55 kJ/mol. How many times faster is the catalyzed than the uncatalyzed reaction at 400°C? Assume that the frequency factor remains the same.
A) / 5.0 times
B) / 1.16 times
C) / 15 times
D) / 2.0 times
E) / 0.2 times
16. / With respect to the figure below, which choice correctly identifies all the numbered positions?
17. / For the reaction X2 + Y + Z ® XY + XZ, it is found that the rate equation is rate = k [X2][Y]. Why does the concentration of Z have no effect on the rate?
A) / The concentration of Z is very small and the others are very large.
B) / Z must react in a step after the rate determining step.
C) / Z is an intermediate.
D) / The fraction of molecules of Z that have very high energies is zero.
E) / The activation energy for Z to react is very high.
18. / Complete the following statement: A catalyst
A) / increases the activation energy.
B) / alters the reaction mechanism.
C) / increases the average kinetic energy of the reactants.
D) / increases the concentration of reactants.
E) / increases the collision frequency of reactant molecules.
19. / The activation energy for the following reaction is 60. kJ/mol.
Sn2+ + 2Co3+ ® Sn4+ + 2Co2+
By what factor (how many times) will the rate constant increase when the temperature is raised from 10°C to 28°C?
A) / 1.002
B) / 4.6
C) / 5.6
D) / 2.8
E) / 696
20. / A certain first-order reaction A ® B is 25% complete in 42 min at 25°C. What is the half-life of the reaction?
A) / 21 min
B) / 42 min
C) / 84 min
D) / 20 min
E) / 101 min
Answer Key
2. / D
3. / A
4. / C
5. / B
6. / A
7. / C
8. / E
9. / E
10. / E
11. / B
12. / C
13. / B
14. / D
15. / A
16. / D
17. / B
18. / B
19. / B
20. / E
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