Question 1

Which of the following best describes the rate law for a zero-order reaction?

Accepted Answer

Rate = k

Question 2

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

Accepted Answer

First-order

Question 3

For a second-order reaction, which of the following expressions gives the half-life ($$t_{1/2}) in $$terms of the initial concentration $$[A]_0$$ and the rate constant $$k$$?

Accepted Answer

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

Question 4

Which factor in the Arrhenius equation $$k = Ae$$^{-E_a/RT}$$ is most affected by increasing the temperature?

Accepted Answer

Exponential factor ($$e^{-E_a/RT})$$

Question 5

A reaction has a rate constant $$k$$ that increases when the temperature is raised. According to the Arrhenius equation, what is the primary reason for this increase?

Accepted Answer

The exponential factor increases

Question 6

In a reaction mechanism, what is a reaction intermediate?

Accepted Answer

A substance that is produced in one step and consumed in a later step

Question 7

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

Accepted Answer

It determines the overall rate law of the reaction

Question 8

For the elementary step $$A + B \rightarrow$$ products, what is the rate law?

Accepted Answer

Rate = k \left[ A \right] \left[ B \right]

Question 9

Which of the following best explains why catalysts increase the rate of a chemical reaction?

Accepted Answer

They provide an alternative pathway with a lower activation energy

Question 10

A reaction is found to be first-order in $$A. If $$the concentration of $$A is $$doubled, what happens to the rate?

Accepted Answer

The rate doubles

Question 11

Which of the following is true about the orientation factor ($$p) in $$collision theory?

Accepted Answer

It is generally less than 1 for complex molecules

Question 12

In the energy diagram for a catalyzed reaction, what is the main difference compared to the uncatalyzed pathway?

Accepted Answer

The catalyzed pathway has a lower activation energy

Question 13

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

Accepted Answer

$$\ln [A]_t = -k t + \ln [A]_0$$

Question 14

Which of the following best describes the effect of increasing temperature on the fraction of molecules with enough energy to overcome the activation energy barrier?

Accepted Answer

The fraction increases

Question 15

In the Arrhenius equation, what does the exponential factor $$e^{-E_a/RT}$$ represent?

Accepted Answer

The fraction of molecules with sufficient energy to react

Question 16

Which of the following is a characteristic of a reaction mechanism?

Accepted Answer

It consists of a series of elementary steps

Question 17

For the reaction $$2 	ext{NO}_2 (g) + 	ext{CO} (g) ightarrow 2 	ext{NO} (g) + 	ext{CO}_2 (g)$$, the observed rate law is $$	ext{Rate} = k [	ext{NO}_2]^2. $$What does this suggest about the mechanism?

Accepted Answer

The rate-determining step involves two NO$$_2$$ molecules

Question 18

Which of the following is true about enzymes as biological catalysts?

Accepted Answer

They orient the substrate for reaction at the active site

Question 19

If a reaction has a rate law $$	ext{Rate} = k [A][B]$$, what is the molecularity of the elementary step?

Accepted Answer

Bimolecular

Question 20

Which of the following is NOT a plausible effect of a catalyst on a reaction?

Accepted Answer

Changing the energy of reactants and products

Chapter 15: Chemical Kinetics – Mini-Textbook Study Notes

Study Guide - Practice Questions

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