Question 1

Which of the following best describes the rate law for a reaction that is first order in A and second order in B?

Accepted Answer

$$	ext{Rate} = k[A][B]^2$$

Question 2

Given the reaction $$	ext{NH}_4^+ (aq) + 	ext{NO}_2^- (aq) ightarrow 	ext{N}_2 (g) + 2	ext{H}_2O (l)$$ and the initial rates in Table 12.4, what is the order of the reaction with respect to $$	ext{NO}_2^-$$?

Accepted Answer

First order

Question 3

Which integrated rate law would produce a straight line when plotting $$\ln[A]$$ versus time?

Accepted Answer

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

Question 4

A reaction is found to be zero order in reactant A. Which of the following statements is true?

Accepted Answer

The rate of reaction does not depend on the concentration of A.

Question 5

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

Accepted Answer

The sum of the elementary steps must equal the overall balanced equation.

Question 6

For a first-order reaction, which of the following is true about the half-life?

Accepted Answer

It is independent of the initial concentration.

Question 7

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 energy equal to or greater than the activation energy.

Question 8

A catalyst increases the rate of a reaction by:

Accepted Answer

Lowering the activation energy of the reaction.

Question 9

Which plot would be linear for a second-order reaction with respect to A?

Accepted Answer

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

Question 10

In the catalytic hydrogenation of ethylene on a metal surface (as shown in the images), what is the role of the metal?

Accepted Answer

It provides a surface for the reactants to adsorb and react, lowering the activation energy.

Question 11

Which of the following is true about the enzyme-substrate complex shown in the last image?

Accepted Answer

The enzyme is not consumed and can catalyze multiple reactions.

Question 12

Given the Arrhenius equation $$k = Ae$$^{-E_a/RT}$$, what does the parameter A represent?

Accepted Answer

The frequency factor, related to the frequency and orientation of collisions.

Question 13

If a reaction is first order in both $$	ext{NH}_4^+$$ and $$	ext{NO}_2^-$$, what is the overall order of the reaction?

Accepted Answer

Second order

Question 14

Which of the following statements about reaction intermediates is correct?

Accepted Answer

They are formed in one step and consumed in a subsequent step of the mechanism.

Question 15

A reaction has a rate law $$	ext{Rate} = k[A]^0. If $$the initial concentration of A is doubled, what happens to the rate?

Accepted Answer

It remains unchanged.

Question 16

Which of the following is a correct statement about the collision model of chemical reactions?

Accepted Answer

Molecules must collide with sufficient energy and proper orientation to react.

Question 17

If the rate constant $$k$$ for a reaction increases with temperature, what can be inferred about the activation energy $$E_a$$?

Accepted Answer

The reaction has a positive activation energy.

Question 18

Which of the following is a characteristic of a heterogeneous catalyst?

Accepted Answer

It is in a different phase than the reactants.

Question 19

For the reaction $$2N_2O_5 (soln) \rightarrow 4NO_2 (soln) + O_2$ (g)$$, the plot of $$\ln[N_2O_5]$$ versus time is linear. What is the order of the reaction with respect to $$N_2O_5$$?

Accepted Answer

First order

Question 20

Which of the following best describes the effect of a catalyst on the activation energy diagram of a reaction?

Accepted Answer

It lowers the height of the energy barrier between reactants and products.

Chapter 12: Chemical Kinetics – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards