Question 1

Which of the following factors does NOT affect the rate of a chemical reaction?

Accepted Answer

Color of the reactants

Question 2

Given the reaction $$2A + B ightarrow C$$, the rate law is found to be $$	ext{rate} = k[A]^2[B]. $$What is the overall order of the reaction?

Accepted Answer

Third order

Question 3

Which of the following best describes the rate constant $$k in $$the rate law $$	ext{rate} = k[A][B]^2$$?

Accepted Answer

It is specific to a given reaction at a specific temperature.

Question 4

A reaction is found to be first order in $$A$$ and zero order in $$B. If $$the concentration of $$A is $$doubled and $$B is $$tripled, how does the rate change?

Accepted Answer

It doubles.

Question 5

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

Accepted Answer

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

Question 6

A student measures the half-life of a reaction and finds it remains constant as the initial concentration changes. What is the order of the reaction?

Accepted Answer

First order

Question 7

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

Accepted Answer

The rate constant $$k$$ decreases as activation energy $$E_a$$ increases.

Question 8

The frequency factor $$A in $$the Arrhenius equation $$k = Ae$$^{-E_a/RT}$$ represents:

Accepted Answer

The number of collisions with proper orientation per unit time.

Question 9

Which of the following best explains why a catalyst increases the rate of a reaction?

Accepted Answer

It lowers the activation energy, allowing more molecules to react.

Question 10

For a reaction mechanism, which step determines the overall rate of the reaction?

Accepted Answer

The slowest step

Question 11

Why can't you generally write the rate law for a reaction from its balanced equation?

Accepted Answer

Because the rate law depends on the mechanism, not just stoichiometry.

Question 12

A reaction has the following mechanism:
Step 1: $$A + B \rightarrow C ($$slow)
Step 2: $$C + D \rightarrow E ($$fast)
What is the rate law for the overall reaction?

Accepted Answer

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

Question 13

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

Accepted Answer

A substance that is formed and consumed during the reaction.

Question 14

If a reaction is second order in $$A$$ and first order in $$B$$, what is the effect on the rate if $$[A] is $$doubled and $$[B] is $$halved?

Accepted Answer

The rate increases by a factor of 2.

Question 15

Which of the following is a correct statement about catalysts?

Accepted Answer

They lower the activation energy and are regenerated at the end.

Question 16

The half-life of a first-order reaction is given by:

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

A plot of $$\ln k$$ versus $$1/T$$ yields a straight line for a reaction. The slope of this line is:

Accepted Answer

$$-E_a/R$$

Question 19

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

Accepted Answer

It increases the number of molecules with energy greater than $$E_a.$$

Question 20

In a real-world scenario, why is it important for pharmaceutical companies to understand reaction mechanisms when designing drugs?

Accepted Answer

To predict and control the rate and selectivity of drug synthesis.

Chapter 14: Chemical Kinetics – Key Concepts and Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards