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

A reaction has the following rate law: $$	ext{rate} = k[NO_2$]^2. If $$the concentration of $$NO_2 is $$doubled, what happens to the rate?

Accepted Answer

The rate increases by a factor of four.

Question 3

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

Accepted Answer

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

Question 4

For a reaction $$A \rightarrow B$$, the half-life for a first-order process is given by:

Accepted Answer

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

Question 5

Which of the following statements about the effect of temperature on reaction rate is correct?

Accepted Answer

Increasing temperature increases the rate constant $$k.$$

Question 6

The Arrhenius equation relates the rate constant $$k to $$temperature $$T as $$follows:

Accepted Answer

$$k = Ae$$^{-E_a/RT}$$

Question 7

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

Accepted Answer

The rate is constant and independent of [A].

Question 8

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

Accepted Answer

It decreases the activation energy.

Question 9

For the reaction $$2NO_2(g) ightarrow 2NO(g) + O_2$(g)$$, the rate law is $$	ext{rate} = k[NO_2$]^2. If $$the initial concentration of $$NO_2 is 0.10 M $$and $$k = 0.54\ 	ext{M}^{-1}	ext{s}^{-1}$$, what is the initial rate?

Accepted Answer

$$0.0054\ 	ext{M s}^{-1}$$

Question 10

Which of the following is the correct expression for the equilibrium constant $$K_c$$ for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

$$K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$$

Question 11

If the equilibrium constant $$K_c$$ for a reaction is much greater than 1, what does this indicate about the reaction at equilibrium?

Accepted Answer

Products are favored.

Question 12

Le Châtelier's Principle predicts that increasing the pressure on the following equilibrium will shift the reaction in which direction? $$N_2(g) + 3H_2(g$$) \rightleftharpoons 2NH_3(g)$$

Accepted Answer

Toward the products

Question 13

Which of the following is true for a reaction at equilibrium?

Accepted Answer

The rates of the forward and reverse reactions are equal.

Question 14

For the reaction $$A ightleftharpoons B$$, if $$K_c = 1.5 	imes 10$$^{-5}$$, which of the following statements is correct?

Accepted Answer

At equilibrium, [A] is much greater than [B].

Question 15

Which of the following changes will increase the value of the equilibrium constant $$K$$ for an exothermic reaction?

Accepted Answer

Decreasing the temperature

Question 16

A reaction mixture initially contains 1.0 M A and 1.0 M B. At equilibrium, 0.4 M of A remains. What is the equilibrium concentration of B if the reaction is $$A + B \rightleftharpoons C$$ and the change in A and B is equal?

Accepted Answer

0.4 M

Question 17

Which of the following is NOT a valid method to increase the rate of a chemical reaction?

Accepted Answer

Decrease the surface area of a solid reactant

Question 18

For a reaction with the rate law $$	ext{rate} = k[A][B]$$, what is the overall order of the reaction?

Accepted Answer

Second order

Question 19

Which of the following best explains why a catalyst does not affect the equilibrium position of a reaction?

Accepted Answer

It increases the rate of both forward and reverse reactions equally.

Chemical Equilibrium: Principles, Calculations, and Applications

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