Question 1

A student is studying the decomposition of CO(NH2)2 in aqueous solution. The concentration of CO(NH2)2 decreases by half every 10 hours. What is the order of the reaction with respect to CO(NH2)2?

Accepted Answer

First order

Question 2

Which of the following graphs would produce a straight line for a first-order reaction?

Accepted Answer

$\ln[A]$ vs. time

Question 3

The rate law for a reaction is $	ext{rate} = k[ClO_2]^2[OH^-]$. If the concentration of $ClO_2$ is tripled and $[OH^-]$ is kept constant, by what factor does the rate increase?

Accepted Answer

9

Question 4

A reaction has the rate law $	ext{rate} = k[A]^2$. If the initial concentration of $A$ is doubled, how does the reaction rate change?

Accepted Answer

It quadruples

Question 5

Which of the following best explains why a powdered metal reacts faster with hydrochloric acid than a metal strip?

Accepted Answer

The powder has a greater surface area

Question 6

For a reaction with the rate law $	ext{rate} = k[A][B]$, what are the units of the rate constant $k$?

Accepted Answer

$\mathrm{M}^{-1}\mathrm{s}^{-1}$

Question 7

A reaction is monitored using a spectrophotometer at 544 nm. The absorbance decreases linearly with time. What does this indicate about the reaction order with respect to the colored reactant?

Accepted Answer

Zero order

Question 8

The half-life of a first-order reaction is 10 minutes. If you start with 64 mg of reactant, how much remains after 50 minutes?

Accepted Answer

2 mg

Question 9

Which of the following changes will NOT increase the rate of a reaction between magnesium and hydrochloric acid?

Accepted Answer

Decreasing the surface area of magnesium

Question 10

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

Accepted Answer

24

Question 11

The Beer-Lambert Law relates absorbance ($A$) to concentration ($c$) by $A = \varepsilon bc$. If the path length ($b$) is doubled, what happens to the absorbance?

Accepted Answer

It doubles

Question 12

For a reaction with a constant half-life, which of the following is true?

Accepted Answer

The reaction is first order

Question 13

Given the rate law $	ext{rate} = k[N_2O_5]$, what are the units of the rate constant $k$?

Accepted Answer

$\mathrm{s}^{-1}$

Question 14

A reaction is second order with respect to $C_4H_6$. If the initial concentration is 0.020 M and the initial rate is $0.0010\ \mathrm{M\ s}^{-1}$, what is the value of the rate constant $k$?

Accepted Answer

$2.5\ \mathrm{M}^{-1}\mathrm{s}^{-1}$

Question 15

If the plot of $1/[A]$ vs. time is linear for a reaction, what is the order of the reaction with respect to $A$?

Accepted Answer

Second order

Question 16

A reaction has a rate constant $k = 0.0693\ \mathrm{min}^{-1}$. What is the half-life for this first-order reaction?

Accepted Answer

10 minutes

Question 17

Which of the following statements about reaction rates is correct?

Accepted Answer

The rate is highest at the beginning of the reaction

Question 18

For a reaction with the rate law $	ext{rate} = k$, what is the order of the reaction?

Accepted Answer

Zero order

Question 19

If the initial concentration of $NO$ in a reaction with rate law $	ext{rate} = k[NO]^2[H_2]$ is doubled, by what factor does the rate increase (assuming $[H_2]$ is constant)?

Accepted Answer

4

Question 20

A student uses a spectrophotometer to monitor the fading of blue food coloring in bleach. If the initial concentration of the dye is increased, what will happen to the time required for the absorbance to reach zero?

Accepted Answer

It will increase

AP Chemistry Study Guide: Chemical Kinetics and Rate Laws (Topics 5.1–5.3)

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