Q: For the reaction $$2O_3(g) \rightarrow 3O_2(g)$$, which expression correctly relates the rate of disappearance of $$O_3 to $$the rate of appearance of $$O_2$$?

$$\text{Rate} = -\frac{1}{2}\frac{\Delta[O_3$]}{\Delta t} = \frac{1}{3}\frac{\Delta[O_2$]}{\Delta t}$$

Question 1

Which of the following best describes the effect of increasing the temperature on the rate of a chemical reaction?

Accepted Answer

It increases the kinetic energy of the molecules, resulting in more frequent and energetic collisions.

Question 2

A reaction is found to be first order in $$[A]$$ and second order in $$[B]. $$What is the correct rate law for this reaction?

Accepted Answer

$$	ext{Rate} = k[A][B]^2$$

Question 3

Which of the following statements about catalysts is TRUE?

Accepted Answer

Catalysts provide an alternative reaction pathway with a lower activation energy.

Question 4

For the reaction $$2O_3(g) \rightarrow 3O_2(g)$$, which expression correctly relates the rate of disappearance of $$O_3 to $$the rate of appearance of $$O_2$$?

Accepted Answer

$$	ext{Rate} = -\frac{1}{2}\frac{\Delta[O_3$]}{\Delta t} = \frac{1}{3}\frac{\Delta[O_2$]}{\Delta t}$$

Question 5

Which of the following is a characteristic of a zero-order reaction?

Accepted Answer

The rate is independent of the concentration of the reactant.

Question 6

The half-life of a first-order reaction is given by which of the following equations?

Accepted Answer

$$t_{1/2} = \frac{0.693}{k}$$

Question 7

Which of the following best explains why a fine powder reacts faster than a solid chunk of the same substance?

Accepted Answer

The powder has a greater surface area, allowing more collisions to occur.

Question 8

A plot of $$\ln[A]$$ versus time yields a straight line for a reaction. What is the order of the reaction with respect to $$A$$?

Accepted Answer

First order

Question 9

Which of the following is NOT a factor that affects the rate of a chemical reaction?

Accepted Answer

The color of the reactants

Question 10

For a reaction with the rate law $$	ext{Rate} = k[A]^2$$, what are the units of the rate constant $$k$$?

Accepted Answer

$$	ext{M}^{-1}	ext{s}^{-1}$$

Question 11

Which statement about the transition state (activated complex) is correct?

Accepted Answer

It is the highest energy state along the reaction pathway.

Question 12

Which of the following best describes the collision model for chemical reactions?

Accepted Answer

Molecules must collide with sufficient energy and proper orientation to react.

Question 13

A reaction has a rate law $$	ext{Rate} = k[A][B]. If $$the concentration of $$A is $$doubled and $$B is $$tripled, by what factor does the rate increase?

Accepted Answer

6

Question 14

Which of the following is true about the rate-determining step in a reaction mechanism?

Accepted Answer

It is the slowest step and limits the overall reaction rate.

Question 15

Which of the following is a correct statement about the effect of a catalyst on a reaction coordinate diagram?

Accepted Answer

It lowers the activation energy ($$E_a) of $$the reaction.

Question 16

For a second-order reaction, which of the following plots yields a straight line?

Accepted Answer

$$\frac{1}{[A]}$$ \, vs. \, t$

Question 17

Which of the following best explains why enzymes are effective biological catalysts?

Accepted Answer

They provide an alternative pathway with lower activation energy for the reaction.

Question 18

If a reaction is zero order in $$[A]$$, what will happen to the rate if $$[A] is $$doubled?

Accepted Answer

The rate will remain the same.

Question 19

Which of the following is the correct integrated rate law for a first-order reaction?

Accepted Answer

$$\ln[A] = -kt + \ln[A]_0$$

Question 20

Which of the following statements about reaction mechanisms is correct?

Accepted Answer

A plausible mechanism must be consistent with the experimentally determined rate law.

Chapter 14: Chemical Kinetics – Study Notes

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