Q: For the reaction $$2\,\text{O}_3 \rightarrow 3\,\text{O}_2$$, if the rate of ozone consumption is $$2.5 \times 10$$^{-5}$$\,\text{mol}\,\text{L}^{-1}\,\text{s}^{-1}$$, what is the rate of $$\text{O}_2$$ production?

$$3.8 \times 10$$^{-5}$$\,\text{mol}\,\text{L}^{-1}\,\text{s}^{-1}$$

Question 1

Which of the following best describes the rate of a chemical reaction?

Accepted Answer

The ratio of the change in concentration of a reactant or product to the elapsed time, $$	ext{Rate} = \frac{\Delta [	ext{substance}]}{\Delta t}$$

Question 2

For the reaction $$2\,	ext{O}_3 ightarrow 3\,	ext{O}_2$$, if the rate of ozone consumption is $$2.5 	imes 10$$^{-5}$$\,	ext{mol}\,	ext{L}^{-1}\,	ext{s}^{-1}$$, what is the rate of $$	ext{O}_2$$ production?

Accepted Answer

$$3.8 	imes 10$$^{-5}$$\,	ext{mol}\,	ext{L}^{-1}\,	ext{s}^{-1}$$

Question 3

Which of the following statements about the rate law $$	ext{Rate} = k[	ext{A}]^2[	ext{B}] is $$correct?

Accepted Answer

The reaction is second order with respect to A, first order with respect to B, and third order overall.

Question 4

A reaction has a rate law $$	ext{Rate} = k[	ext{A}]. If $$the concentration of A is tripled, what happens to the rate?

Accepted Answer

The rate triples.

Question 5

Given the following data for the decomposition of $$	ext{N}_2	ext{O}_5$$: 
Experiment 1: $$[	ext{N}_2	ext{O}_5] = 3.0 	imes 10$$^{-2}$$\,	ext{mol}\,	ext{L}^{-1}$$, Rate $$= 9.0 	imes 10$$^{-5}$$\,	ext{mol}\,	ext{L}^{-1}\,	ext{s}^{-1}$$
Experiment 2: $$[	ext{N}_2	ext{O}_5] = 9.0 	imes 10$$^{-2}$$\,	ext{mol}\,	ext{L}^{-1}$$, Rate $$= 2.7 	imes 10$$^{-4}$$\,	ext{mol}\,	ext{L}^{-1}\,	ext{s}^{-1}$$
What is the order of the reaction with respect to $$	ext{N}_2	ext{O}_5$$?

Accepted Answer

First order

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

First order

Question 8

The rate constant $$k$$ for a reaction is found to increase with temperature. Which equation best describes this relationship?

Accepted Answer

$$k = Ae$$^{-E_a/(RT)}$$

Question 9

In a laboratory experiment, ozone ($$	ext{O}_3) is $$exposed to UV radiation with a first-order rate constant $$k = 0.10\,	ext{day}^{-1}. If $$the initial concentration is $$5.0\,	ext{mM}$$, what is the concentration after 1.0 day?

Accepted Answer

$$2.1\,	ext{mM}$$

Question 10

Which of the following statements about the activation energy ($$E_a) of a $$reaction is correct?

Accepted Answer

It is the minimum energy that reactant molecules must possess for a reaction to occur.

Question 11

Which of the following is a property of a catalyst in a chemical reaction?

Accepted Answer

It increases the rate of reaction by providing an alternative pathway with lower activation energy.

Question 12

A reaction mechanism consists of the following steps:
1. $$	ext{A} ightarrow 	ext{B} ($$slow)
2. $$	ext{B} + 	ext{C} ightarrow 	ext{D} ($$fast)
What is the rate law for the overall reaction?

Accepted Answer

$$	ext{Rate} = k[	ext{A}]$$

Question 13

Which of the following best describes a reactive intermediate in a reaction mechanism?

Accepted Answer

A species that is formed in one step and consumed in a subsequent step of the mechanism.

Question 14

For a second-order reaction with rate law $$	ext{Rate} = k[	ext{A}]^2$$, which of the following plots will yield a straight line?

Accepted Answer

$$\frac{1}{[A]}$$ versus time

Question 15

Which of the following is NOT a characteristic of a homogeneous catalyst?

Accepted Answer

It is in a different phase than the reactants.

Question 16

In the context of atmospheric chemistry, what is the primary role of NO in the formation of tropospheric ozone?

Accepted Answer

It reacts with ozone, preventing its accumulation.

Question 17

Which of the following best explains why increasing temperature generally increases the rate of a chemical reaction?

Accepted Answer

A greater fraction of molecules have sufficient kinetic energy to overcome the activation energy barrier.

Question 18

A plot of $$\ln k$$ versus $$1/T$$ for a reaction yields a straight line with a negative slope. What does the magnitude of the slope represent?

Accepted Answer

$$-E_a/R$$, where $$E_a is $$the activation energy and $$R is $$the gas constant.

Question 19

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

Accepted Answer

It is the slowest step and determines the overall rate law of the reaction.

Chemical Kinetics: Principles, Atmospheric Applications, and Ozone Depletion

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