6. Balance the reaction below in acidic aqueous solution, using the oxidation number method. In the balanced equation, what is the coefficient of ? 

(A) 1
(B) 4
(C) 5
(D) 7
(E) 8

2. The value of the equilibrium constant K depends on: I: the initial concentrations of the reactants； II: the initial concentrations of the products, III: the final concentrations of the reactants, IV: the final concentrations of the products. (A) I and II only (B) II and III only (C) III and IV only (D) three of these (E) none of these

3. The number of wall impacts per second versus the square root of Kelvin temperature for 1 mol of an ideal gas at constant volume. Which graph represents the plot? (A) (B) (C) (D) (E) none of these

4. Which statement about kinetic energy (K.E.) is true? (A) all objects moving with the same velocity have the same KE (B) as the velocity of a body increases, its K.E. decreases (C) the K.E. of a body will double if its velocity doubles (D) the K.E. of a body is independent of its mass (E) none of these statements is true

5. Aqueous solutions of lead nitrate and potassium chloride are mixed and a precipitate forms. Which pair of ions are spectator ions? (A) (B) (C) (D) (E) all of above

7. You have separate aqueous solutions of NaOH and Ca(OH)2 with the same concentrations. You wish to neutralize an aqueous solution of HCl. Which basic solution would require more volume to neutralize the acid? (A) the NaOH solution (B) the Ca(OH)2 solution (C) you need to know the concentrations of the basic solutions to answer this question (D) you need to know the volume and concentration of the HCl solution to answer this question (E) you need to know the concentrations of the acid and bases and the volume of the acid to answer this question

8. As water is heated, its pH decreases. This means that (A) the water is no longer neutral (B) (C) two of these are correct (D) none of these is correct

9. The acids HC2H3O2 and HF are both weak, but HF is a stronger acid than HC2H3O2. HCl is a strong acid. Order the following according to base strength. (A) (B) (C) (D) F¯ ＞ (E) none of these

10. For which of the following reaction(s) is the enthalpy change for the reaction not equal to of the product? I: 2H(g) → H2(g), II: H2(g) + O2(g) → H2O2(1), III: H2O(l) + O(g) → H2O2(1) (A) I only (B) II only (C) III only (D) I and III (E) II and III

11. For a particular process q = -10 kJ and w = 25 kJ. Which of the following statements is true? (A) heat flows from the surroundings to the system (B) the system does work on the surroundings (C) ΔΕ = −35 kJ (D) all of these are true (E) none of these is true

12. For a spontaneous endothermic process, which conditions must hold? (1)  = △G (2)  ＞ 0 (3) △S cannot be negative (4) △S is positive. (A) all (B) none (C) 1 and 3 only (D) 1, 2, and 4 only (E) 3 and 4 only