University of Kentucky - Department of Chemistry
1. Which of the following is true at equilibrium?A. All reaction stops. B. Amounts of reactants and products are equal. C. Amounts of reactants and products are constant. D. The rate of the forward reaction is greater than the rate of the reverse reaction.
2. For the equilibrium
4 KO2(s) + 2 H2O(g) = 4 KOH(s) + 3 O2(g) the equilibrium constant expression is given by
A. Kc = [O2]3 / [H2O]2 B. Kc = [KOH]4[O2]3 / [KO2]4[H2O]2 C. Kc = [O2]1/3 / [H2O]1/2 D. Kc = [H2O] / [O2]
3. For a certain gaseous reaction at 1000 K, the value of Kp = 2.82 x 103, and that of Kc = 5.63 x 10-4. What is the value of delta n?A. 3.50 B. 0.227 C. -3.50 D. -0.227
4. Given Kp = 4.60 x 10-14 for
2 Cl2(g) + 2 H2O(g) = 4 HCl(g) + O2(g). What is Kp for
2 HCl(g) + 1/2 O2(g) = Cl2(g) + H2O(g) ? A. 2.17 x 1013 B. 4.66 x 106 C. 2.12 x 10-27 D. 2.14 x 10-7
5. In the following reaction,
H2(g) + I2(g) = 2 HI(g), if [H2] = [I2] = [HI] = 1.75 x 10-3 M and Kc = 50.2 at 445oC, which of the following statements is true?
A. The system is at equilibrium. B. All of the concentrations will increase as the system moves toward equilibrium. C. [H2] and [I2] will increase as the system moves toward equilibrium. D. [HI] will increase as the system moves toward equilibrium.
6. Some ammonia is sealed in a container and allowed to equilibrate at some constant temperature. The reaction is endothermic.
2 NH3(g) = N2(g) + 3 H2(g) Which of the following will cause the reaction to proceed to the right? 1. Some ammonia is added. 2. Some hydrogen is added. 3. The volume of the container is decreased. 4. The temperature is increased.
A. 1 and 2 B. 1 and 3 C. 1 and 4 D. 2 and 4
7. Predict the shift in equilibrium position that will occur for each of the following processes when the volume is decreased:1. P4(s) + 6 Cl2(g) = 4 PCl3(l) 2. PCl3(g) + Cl2(g) = PCl5(g) 3. PCl3(g) + 3 NH3(s) = P(NH2)3(g) + 3 HCl(s)
1 2 3 A. left right no shift B. right left left C. no shift right left D. right right no shift
8. Initially 0.656 moles of A and 0.433 moles of B were placed in a 1.00 L container. After equilibrium was reached the concentration of A was found to be 0.511 M. What is Kc for the reaction
2 A(g) + B(g) = C(g) at the temperature of the experiment?
A. 0.770 B. 1.93 C. 0.394 D. 2.74
9. 0.152 mol of phosphorus pentachloride is sealed in a 3.04 L container at 625 K. At this temperature, Kc for the equilibrium
PCl5(g) = PCl3(g) + Cl2(g) is 0.620. Calculate the concentration in moles per liter of all species present after equilibrium is attained.
[PCl5] [PCl3] [Cl2] A. 0.0123 0.0875 0.0875 B. 0.00350 0.0465 0.0465 C. 0.0875 0.0123 0.0875 D. 0.0465 0.00350 0.0465
10. What is the solubility product constant for silver phosphate if the solubility of Ag3PO4 is 4.4 x 10-5 M ?A. 3.7 x 10-18 B. 1.0 x 10-16 C. 5.8 x 10-9 D. 9.1 x 10-16
11. The solubility product for magnesium hydroxide (formula mass = 58.32 g mol-1) is 8.9 x 10-12 at 25oC. Calculate the solubility in g/L of magnesium hydroxide at 25oC.A. 1.2 x 10-2 g/L B. 1.3 x 10-4 g/L C. 7.6 x 10-3 g/L D. 3.0 x 10-6 g/L
12. What is the molar solubility of MgF2, Ksp = 8.0 x 10-8, in a 0.20 M solution of KF?A. 8.0 x 10-8 M B. 4.0 x 10-7 M C. 2.0 x 10-6 M D. 2.7 x 10-4 M
13. Which of the following are conjugate acid-base pairs?1. H2SO4, HSO3- 2. NH4+, NH3 3. H3PO4, HPO42- 4. CH3COOH, CH3COOH2+
A. 1 and 2 B. 2 and 4 C. 2 and 3 D. 1 and 3
14. At 37oC, Kw = 2.4 x 10-14. Calculate the pH and pOH for a neutral aqueous solution at this temperature.A. 7.00 each B. 6.81 each C. 6.81 and 7.19 D. 7.19 each
15. For the equilibrium
CH3COOH(aq) + H2O(l) = CH3COO-(aq) + H3O+(l) Ka = 1.70 x 10-4 at 250 K. What is the effect on the pH and on [H3O+] of adding 50 mL of 0.01 M CH3COONa to the solution?
1. pH value decreases 2. pH value increases 3. [H3O+] increases 4. [H3O+] decreases
A. 1 and 4 B. 2 and 4 C. 2 and 3 D. 1 and 3
16. What are the pH, pOH, and OH- ion concentration in moles per liter in a 0.25 M HCl solution?pH pOH [OH-] A. 0.60 13.40 4.0 x 10-14 B. 13.40 0.60 2.5 x 10-15 C. -0.60 14.60 2.5 x 10-15 D. 13.40 0.60 4.0 x 10-14
17. Calculate the pH of a 3.5 x 10-3 M Ba(OH)2 solution.A. 2.15 B. 3.50 C. 11.85 D. 10.50
18. A 0.017 M solution of a weak monoprotic acid has a pH of 3.89. Calculate the Ka of this acid.A. 1.0 x 10-6 B. 1.3 x 10-4 C. 1.7 x 10-8 D. 9.8 x 10-7
19. Calculate the molar concentration of the nitrite ion and the percentage ionization of a 0.15 M solution of nitrous acid, HNO2, whose Ka is 4.6 x 10-4.A. [NO2-] = 8.1 x 10-3 M, 5.4% B. [NO2-] = 0.15 M, 100% C. [NO2-] = 2.1 x 10-2 M, 14% D. [NO2-] = 8.1 x 10-3 M, 0.83%
20. Which of the following are strong acids?
HCl, CH3COOH, HClO4, H3PO4, HCN, HNO3 A. H3PO4, HCl, HCN B. H3PO4, HCl, HClO4 C. CH3COOH, H3PO4, HCN D. HCl, HClO4, HNO3
21. The equilibrium constant for the reaction with water of the acid HB+, conjugate to the base B, isA. Kw2/KaKb B. Kw/KaKb C. Kw/Ka D. Kw/Kb
22. Classify the following solutions as acidic (A), basic (B), or neutral (N).
1. KClO4(aq) 2. LiCN(aq) 3. NH4NO3(aq) 4. NaOCl(aq) A. 1A, 2B, 3B, 4B B. 1B, 2B, 3A, 4B C. 1A, 2B, 3N, 4N D. 1N, 2B, 3A, 4B
23. What is the pH of the solution prepared by dissolving 0.25 moles of KF in enough water to prepare 1.0 L of solution. Ka for HF is 3.5 x 10-4.A. 5.27 B. 7.00 C. 8.43 D. 10.54
24. In which of the following is the stronger acid listed first?A. H2SO3, H2SO4 B. HBr, HI C. H2O, H2S D. HClO2, HClO
25. Identify the Lewis acids in the following reactions
HNO2(aq) + OH-(aq) = NO2-(aq) + H2O(l) FeBr3(s) + Br-(aq) = FeBr4-(aq) Zn2+(aq) + 4 NH3(aq) = Zn(NH3)42+(aq) A. HNO2, FeBr3, NH3 B. OH-, Br-, NH3 C. HNO2, FeBr3, Zn2+ D. OH-, Br-, Zn2+