$$t_{1/2} = \frac{1}{0.50 \times 0.10}$$

Question 1

Which of the following statements best describes the half-life of a first-order reaction?

Accepted Answer

The half-life is constant and independent of the initial concentration.

Question 2

For a reaction following second-order kinetics, what is the correct integrated rate law for a single reactant?

Accepted Answer

$$\frac{1}{[A]_t} = kt + \frac{1}{[A]_0}$$

Question 3

A plot of $$\ln[A]_t$$ versus time yields a straight line for which type of reaction?

Accepted Answer

First order

Question 4

If the initial concentration of a reactant in a zeroth-order reaction is doubled, what happens to the rate?

Accepted Answer

The rate remains the same.

Question 5

Which equation correctly expresses the half-life for a second-order reaction?

Accepted Answer

$$t_{1/2} = \frac{1}{k[A]_0}$$

Question 6

Radioactive decay of $$^{14}C is an $$example of which order of reaction?

Accepted Answer

First order

Question 7

For a first-order reaction, what is the unit of the rate constant $$k$$?

Accepted Answer

$$s^{-1}$$

Question 8

In a second-order reaction, what happens to the rate if the concentration of the reactant is doubled?

Accepted Answer

The rate quadruples.

Question 9

Which plot is diagnostic for a zeroth-order reaction?

Accepted Answer

A plot of $$[A]_t vs. $$time yields a straight line.

Question 10

A reaction has a rate law $$	ext{Rate} = k[A]^2. If$$ $$[A]_0 = 0.10 M $$and $$k = 0.50 M$^{-1}s$^{-1}$$, what is the half-life?

Accepted Answer

$$t_{1/2} = \frac{1}{0.50 	imes 0.10}$$

Question 11

For a zeroth-order reaction, which of the following statements is true about the half-life as the reaction proceeds?

Accepted Answer

Each subsequent half-life becomes shorter than the previous one.

Question 12

A student is analyzing a reaction and finds that a plot of $$1/[A]_t vs. $$time is linear. What is the order of the reaction?

Accepted Answer

Second order

Question 13

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

Accepted Answer

$$[A]_t = -kt + [A]_0$$

Question 14

The decomposition of ozone in the atmosphere is catalyzed by atomic chlorine and follows which order of kinetics?

Accepted Answer

First order

Question 15

If a reaction follows first-order kinetics and the rate constant $$k is 0.271 s$^{-1}$$, what is the half-life?

Accepted Answer

$$t_{1/2} = \frac{0.693}{0.271}$$

Question 16

Which of the following best describes the change in half-life for a second-order reaction as the concentration decreases?

Accepted Answer

The half-life increases.

Question 17

A reaction has a rate law $$	ext{Rate} = k. $$What is the order of the reaction?

Accepted Answer

Zeroth order

Question 18

Which of the following is a real-world example of a first-order reaction?

Accepted Answer

Radioactive decay of carbon-14

Question 19

For a zeroth-order reaction, what is the correct expression for half-life?

Accepted Answer

$$t_{1/2} = \frac{[A]_0}{2k}$$

Question 20

Which of the following is NOT a characteristic of a first-order reaction?

Accepted Answer

The rate quadruples if the concentration is doubled.

Integrated Rate Laws and Half-Life in Chemical Kinetics

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