$$\text{Rate} = -\frac{1}{2} \frac{\Delta [N_2O_5]}{\Delta t}$$

Question 1

Which of the following best describes the rate of a chemical reaction?

Accepted Answer

The change in the amount of a reactant or product per unit time.

Question 2

Given the reaction $$2N_2O_5(g) \rightarrow 4NO_2(g) + O_2$(g)$$, which is the correct rate expression in terms of $$[N_2O_5]$$?

Accepted Answer

$$	ext{Rate} = -\frac{1}{2} \frac{\Delta [N_2O_5]}{\Delta t}$$

Question 3

Which factor does NOT generally increase the rate of a chemical reaction?

Accepted Answer

Decreasing the temperature.

Question 4

According to collision theory, which of the following is necessary for a reaction to occur?

Accepted Answer

Reactant molecules must collide with sufficient energy and proper orientation.

Question 5

For a first-order reaction, which of the following is the correct integrated rate law?

Accepted Answer

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

Question 6

Which statement about the rate constant $$k is $$correct?

Accepted Answer

$$k is $$specific for a particular reaction at a particular temperature.

Question 7

A reaction is found to be second order with respect to $$A. If $$the concentration of $$A is $$doubled, what happens to the reaction rate?

Accepted Answer

The rate increases by a factor of 4.

Question 8

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

Accepted Answer

It provides an alternate pathway with a lower activation energy.

Question 9

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

Accepted Answer

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

Question 10

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

Accepted Answer

The rate is independent of the concentration of the reactant.

Question 11

Which of the following is the correct two-point form of the Arrhenius equation?

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 12

Which of the following is an example of a heterogeneous catalyst?

Accepted Answer

Platinum in a catalytic converter for automobile exhaust.

Question 13

A reaction has the rate law $$	ext{Rate} = k[A][B]^2. $$What is the overall order of the reaction?

Accepted Answer

3

Question 14

Which of the following statements about the activation energy ($$E_a) is $$correct?

Accepted Answer

It is the minimum energy required for a reaction to occur.

Question 15

If a reaction is first order in $$A$$ and zero order in $$B$$, how does doubling $$[B]$$ affect the rate?

Accepted Answer

The rate remains unchanged.

Question 16

Which of the following best describes the effect of increasing temperature on a reaction rate?

Accepted Answer

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

Question 17

Which of the following is true about enzymes?

Accepted Answer

They are biological catalysts that speed up reactions in living systems.

Question 18

Which of the following is a correct statement about the half-life of a second-order reaction?

Accepted Answer

It depends on the initial concentration of the reactant.

Question 19

Which of the following is NOT a postulate of collision theory?

Accepted Answer

Reactant molecules must have the same mass.

Question 20

A reaction is monitored and the plot of $$\ln [A]$$ versus time is linear. What is the order of the reaction with respect to $$A$$?

Accepted Answer

First order

Chemical Kinetics: Reaction Rates, Rate Laws, and Catalysis

Study Guide - Practice Questions