Question 1

For the reaction $$A ightarrow$$ products, the following data were collected:

$$\begin{array}{cc}
[A] \ (M) & 	ext{Initial Rate} \ (M/s) \
0.10 & 0.015 \
0.20 & 0.030 \
0.40 & 0.060 \
\end{array}$$

What is the order of the reaction with respect to $$A$$?

Accepted Answer

First order

Question 2

A reaction is found to be second order with respect to $$A. If $$the initial rate is $$0.0100 M/s at$$ $$[A] = 0.100 M$$, what will the initial rate be at $$[A] = 0.500 M$$?

Accepted Answer

$$0.250 M/s$$

Question 3

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

Accepted Answer

$$\ln[A] vs. $$time

Question 4

For a zero-order reaction, which of the following statements is true?

Accepted Answer

The rate is independent of the concentration of the reactant.

Question 5

Given the following data for the reaction $$2NO_2(g) + CO(g) ightarrow 2CO_2(g) + N_2$(g)$$:

$$\begin{array}{ccc}
[NO_2$] \ (M) & [CO] \ (M) & 	ext{Initial Rate} \ (M/s) \
0.10 & 0.10 & 0.0021 \
0.20 & 0.10 & 0.0082 \
0.20 & 0.20 & 0.0083 \
0.40 & 0.10 & 0.033 \
\end{array}$$

What is the order of the reaction with respect to $$CO$$?

Accepted Answer

Zero order

Question 6

A first-order reaction has a half-life of 25 minutes. If the initial concentration of $$A is$$ $$0.300 M$$, what is the concentration of $$A$$ after 50 minutes?

Accepted Answer

$$0.150 M$$

Question 7

Which of the following best explains why reaction rates generally increase with increasing temperature?

Accepted Answer

Because a greater fraction of molecules have enough thermal energy to surmount the activation barrier.

Question 8

The Arrhenius equation is $$k = Ae$$^{-E_a/RT}$$. What does the exponential factor e$$^{-E_a/RT}$$ represent?

Accepted Answer

The fraction of molecules with enough energy to overcome the activation barrier.

Question 9

For a reaction with the integrated rate law $$\ln[A]_t = -kt + \ln[A]_0$$, what is the order of the reaction?

Accepted Answer

First order

Question 10

A decomposition reaction is observed to slow down as the reaction proceeds, and its half-life depends on the initial concentration of the reactant. Which statement is most likely true for this reaction?

Accepted Answer

A doubling of the initial concentration of the reactant results in a quadrupling of the rate.

Question 11

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

Accepted Answer

$$\dfrac{1}{[A]_t} = kt + \dfrac{1}{[A]_0}$$

Question 12

If a reaction is zero order in $$A$$, what will happen to the rate if $$[A] is $$tripled?

Accepted Answer

The rate will remain the same.

Question 13

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

Accepted Answer

Third order

Question 14

Which of the following statements about activation energy is correct?

Accepted Answer

It is the minimum energy needed to convert reactants into the activated complex.

Question 15

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

Accepted Answer

It is constant and independent of concentration.

Question 16

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

Accepted Answer

18

Question 17

Which of the following best describes the effect of increasing activation energy $$E_a on $$the rate constant $$k ($$all else constant)?

Accepted Answer

The rate constant decreases.

Question 18

Given the Arrhenius equation $$k = Ae$$^{-E_a/RT}$$, which of the following changes will increase the rate constant k$?

Accepted Answer

Increase the temperature.

Question 19

Reaction A and reaction B have identical frequency factors. However, reaction B has a higher activation energy than reaction A. Which reaction has a greater rate constant at room temperature?

Accepted Answer

Reaction A

Question 20

A student is studying the decomposition of $$SO_2Cl_2$$ and finds that a plot of $$\ln[SO_2Cl_2]$$ versus time is a straight line with a negative slope. What does this indicate about the reaction order?

Accepted Answer

The reaction is first order.

Chemical Kinetics: Reaction Rates and Rate Laws

Study Guide - Practice Questions

Study Guide - Flashcards