AP Chemistry Practice Test 9

Questions 1-4 refer to the following information.

Consider the Lewis structures for the following molecules:

CO2, CO32-, NO2-, and NO3-

1. Which molecule would have the shortest bonds?

2. Which molecules are best represented by multiple resonance structures?

3. Which molecule or molecules exhibit sp2 hybridization around the central atom?

4. Which molecule would have the smallest bond angle between terminal atoms?

5. NH4+(aq) + NO2- (aq) → N2(g) + 2H2O(l)

Increasing the temperature of the above reaction will increase the rate of reaction. Which of the following is NOT a reason that increased temperature increases reaction rate?

6. Which of the following diagrams best represents what is happening on a molecular level when NaCl dissolves in water?

7. Nitrous acid, HNO2, has a pKa value of 3.3. If a solution of nitrous acid is found to have a pH of 4.2, what can be said about the concentration of the conjugate acid/base pair found in solution?

8. Which of the following processes is an irreversible reaction?

Questions 9-13 refer to the following information.

A sample of H2S gas is placed in an evacuated, sealed container and heated until the following decomposition reaction occurs at 1000 K:

2H2S(g) → 2H2(g) + S2(g) Kc = 1.0 × 10-6

9. Which of the following represents the equilibrium constant for this reaction?

10. Which of the following graphs would best represent the change in concentration of the various species involved in the reaction over time?

11. Which option best describes what will immediately occur to the reaction rates if the pressure on the system is increased after it has reached equilibrium?

12. If, at a given point in the reaction, the value for the reaction quotient Q is determined to be 2.5 × 10-8, which of the following is occurring?

13. As the reaction progresses at a constant temperature of 1,000K, how does the value for the Gibbs free energy constant for the reaction change?