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

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

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

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

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

13. Choose the correct statement. (A) exothermic reactions are always spontaneous (B) free energy is independent of temperature (C) a reaction that exhibits a negative value of AS cannot be spontaneous (D) at constant pressure and temperature, a decrease in free energy ensures an increase in the entropy of the system (E) none of these

14. When the equation for the following reaction in basic solution is balanced, what is the sum of the coefficients? (A) 11 (B) 31 (C) 14 (D) 9 (E) 18

15. From the following list of observations, choose the one that most clearly supports the conclusion that electrons have wave properties. (A) the emission spectrum of hydrogen (B) the photoelectric effect (C) the scattering of alpha particles by metal foil (D) diffraction (E) cathode "rays"