Kinetics Multiple Choice Review Questions for AP Chemistry (page 2)

Review the following concepts if necessary:

• Rates of Reaction for AP Chemistry
• Integrated Rate Laws for AP Chemistry
• Reaction Mechanisms for AP Chemistry
• Activation Energy and Catalysts for AP Chemistry

Problems

You have 15 minutes. You may not use a calculator. You may use the periodic table at the back of the book. For each question, circle the letter of your choice.

1. A reaction follows the rate law: Rate = k[A]². Which of the following plots will give a straight line?
   1. 1/[A] versus 1/time
   2. [A]² versus time
   3. 1/[A] versus time
   4. ln[A] versus time
   5. [A] versus time
2. For the following reaction: NO₂(g) + CO(g) → NO(g) + CO₂(g), the rate law is: Rate = k[NO₂]². If a small amount of gaseous carbon monoxide (CO) is added to a reaction mixture that was 0.10 molar in NO₂ and 0.20 molar in CO, which of the following statements is true?
   1. Both k and the reaction rate remain the same.
   2. Both k and the reaction rate increase.
   3. Both k and the reaction rate decrease.
   4. Only k increases, the reaction rate remains the same.
   5. Only the reaction rate increases; k remains the same.
3. The specific rate constant, k, for radioactive beryllium–11 is 0.049 s^–1. What mass of a 0.500 mg sample of beryllium–11 remains after 28 seconds?
   1. 0.250 mg
   2. 0.125 mg
   3. 0.0625 mg
   4. 0.375 mg
   5. 0.500 mg
4. The slow rate of a particular chemical reaction might be attributed to which of the following?
   1. a low activation energy
   2. a high activation energy
   3. the presence of a catalyst
   4. the temperature is high
   5. the concentration of the reactants are high
5. The steps below represent a proposed mechanism for the catalyzed oxidation of CO by O₃.
   Step 1: NO₂(g) + CO(g) → NO(g) + CO₂(g)
   Step 2: NO(g) + O₃(g) → NO₂(g) + O₂(g)

What are the overall products of the catalyzed reaction?

1. CO₂ and O₂
2. NO and CO₂
3. NO₂ and O₂
4. NO and O₂
5. NO₂ and CO₂
6. The decomposition of ammonia to the elements is a first–order reaction with a half–life of 200 s at a certain temperature. How long will it take the partial pressure of ammonia to decrease from 0.100 atm to 0.00625 atm?
   1. 200 s
   2. 400 s
   3. 800 s
   4. 1000 s
   5. 1200 s
7. The energy difference between the reactants and the transition state is
   1. the free energy
   2. the heat of reaction
   3. the activation energy
   4. the kinetic energy
   5. the reaction energy
8. The purpose of striking a match against the side of a box to light the match is
   1. to supply the free energy for the reaction
   2. to supply the activation energy for the reaction
   3. to supply the heat of reaction
   4. to supply the kinetic energy for the reaction
   5. to catalyze the reaction
9. The table below gives the initial concentrations and rate for three experiments.



The reaction is CO(g) + Cl₂(g) → COCl₂(g). What is the rate law for this reaction?

1. Rate = k[CO]
2. Rate = k[CO]²[Cl₂]
3. Rate = k[Cl₂]
4. Rate = k[CO][Cl₂]²
5. Rate = k[CO][Cl₂]
10. The reaction (CH₃)₃CBr(aq) + H₂O(l) → (CH₃)₃COH(aq) + HBr(aq) follows the rate law: Rate = k[(CH₃)₃CBr]. What will be the effect of decreasing the concentration of (CH₃)₃CBr?
    1. The rate of the reaction will increase.
    2. More HBr will form.
    3. The rate of the reaction will decrease.
    4. The reaction will shift to the left.
    5. The equilibrium constant will increase.
11. When the concentration of H⁺(aq) is doubled for the reaction H₂O₂(aq) + 2 Fe²⁺(aq) + 2 H⁺(aq) → 2 Fe³⁺(aq) + 2 H₂O(g), there is no change in the reaction rate. This indicates
    1. the H⁺ is a spectator ion
    2. the rate-determining step does not involve H⁺
    3. the reaction mechanism does not involve H⁺
    4. the H⁺ is a catalyst
    5. the rate law is first order with respect to H⁺
12. The mechanism below has been proposed for the reaction of CHCl₃ with Cl₂.
    Step l: Cl₂ 2 Cl(g) fast
    Step 2: Cl(g) + CHCl₃(g) → CCl₃(g) + HCl(g) slow
    Step 3: CCl₃(g) + Cl(g) → CCl₄(g) fast

Which of the following rate laws is consistent with this mechanism?

1. Rate = k[Cl₂]
2. Rate = k[CHCl₃][Cl₂]
3. Rate = k[CHCl₃]
4. Rate = k[CHCl₃]/[Cl₂]
5. Rate = k[CHCl₃][Cl₂]^1/2