Q: For a reaction with the rate law $$\text{rate} = k[\text{A}]^2$$, which of the following statements is true?

Doubling $$[\text{A}]$$ will quadruple the rate.

Question 1

Which of the following best describes the effect of a catalyst on a chemical reaction?

Accepted Answer

A catalyst lowers the activation energy $$E_a$$ and increases the reaction rate.

Question 2

For a reaction with the rate law $$	ext{rate} = k[	ext{A}]^2$$, which of the following statements is true?

Accepted Answer

Doubling $$[	ext{A}]$$ will quadruple the rate.

Question 3

A reaction is found to be first order in $$	ext{A}$$ and zero order in $$	ext{B}. $$Which is the correct rate law?

Accepted Answer

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

Question 4

Which of the following is true for a zero-order reaction?

Accepted Answer

The rate is independent of the concentration of reactant.

Question 5

The half-life for a first-order reaction is given by which equation?

Accepted Answer

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

Question 6

Which of the following statements about the Arrhenius equation is correct?

Accepted Answer

The Arrhenius equation relates the rate constant $$k to $$temperature and activation energy.

Question 7

A reaction mechanism consists of the following steps:
Step 1: $$	ext{A} + 	ext{B} ightarrow 	ext{C} ($$slow)
Step 2: $$	ext{C} ightarrow 	ext{D} ($$fast)
What is the rate-determining step?

Accepted Answer

Step 1

Question 8

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

Accepted Answer

It increases the number of molecules with sufficient energy to overcome the activation barrier.

Question 9

Which of the following is a valid reason for a proposed reaction mechanism to be rejected?

Accepted Answer

The sum of the elementary steps does not match the overall reaction.

Question 10

A student observes that the plot of $$\ln[	ext{A}]$$ versus time is a straight line for a reaction. What is the order of the reaction?

Accepted Answer

First order

Question 11

Which of the following is true about the molecularity of an elementary reaction?

Accepted Answer

It refers to the number of molecules involved in a single step.

Question 12

Which of the following best describes a reaction intermediate?

Accepted Answer

A species that is formed and consumed during the reaction mechanism.

Question 13

The rate law for a reaction is $$	ext{rate} = k[	ext{A}]^1[	ext{B}]^2. If$$ $$[	ext{A}] is $$doubled and $$[	ext{B}] is $$tripled, by what factor does the rate increase?

Accepted Answer

18

Question 14

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

Accepted Answer

It increases the yield of product at equilibrium.

Question 15

Which of the following best describes the effect of a biological enzyme on a reaction?

Accepted Answer

It increases the rate by lowering $$E_a$$ without altering $$\Delta H.$$

Question 16

A reaction has a rate constant $$k$$ that increases from $$1.0 	imes 10$$^{-3}$$ \ 	ext{s}^{-1} to$$ $$4.0 	imes 10$$^{-3}$$ \ 	ext{s}^{-1}$$ when the temperature is raised from $$300\ 	ext{K} to$$ $$310\ 	ext{K}. $$Which equation would you use to calculate the activation energy $$E_a$$?

Accepted Answer

$$\ln\left(\frac{k_2$}{k_1$}\right) = -\frac{E_a}{R}\left(\frac{1}{T_2$} - \frac{1}{T_1$}\right)$$

Question 17

Which of the following is a correct statement about the collision model for reaction rates?

Accepted Answer

Only collisions with energy greater than or equal to $$E_a$$ can lead to reaction.

Question 18

Which of the following is true for a second-order reaction with respect to $$	ext{A}$$?

Accepted Answer

A plot of $$1/[	ext{A}]$$ versus time is linear.

Question 19

Which of the following is a valid method for determining the order of a reaction experimentally?

Accepted Answer

Measuring the initial rate at different concentrations of reactant.

Question 20

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.

Chemical Kinetics: Reaction Rates and Mechanisms (AP Chemistry Unit 5 Study Guide)

Study Guide - Practice Questions

Study Guide - Flashcards