Question 1

Refer to the first image. Which balanced chemical equation is represented by the molecular models shown?

Accepted Answer

$\mathrm{H_2} + \mathrm{I_2} \rightarrow 2\,\mathrm{HI}$

Question 2

Based on the second image, which reaction order shows a straight-line decrease in reactant concentration versus time?

Accepted Answer

Zero order

Question 3

According to the third image, what is true about the half-life of a first-order reaction?

Accepted Answer

It is constant and independent of concentration.

Question 4

Using the activation energy diagram (fourth image), what does the peak of the curve represent?

Accepted Answer

The transition state (activated complex)

Question 5

Refer to the thermal energy distribution graph (fifth image). What happens to the fraction of molecules with enough energy to react as temperature increases?

Accepted Answer

It increases

Question 6

In the Arrhenius plot (sixth image), what does the slope of the line represent?

Accepted Answer

$-\dfrac{E_a}{R}$

Question 7

Based on the collision theory illustration (seventh image), what is required for a successful reaction between molecules?

Accepted Answer

A collision with sufficient energy and proper orientation

Question 8

For the reaction $2\,\mathrm{NOCl}(g) \rightarrow 2\,\mathrm{NO}(g) + \mathrm{Cl_2}(g)$ (eighth image), what is the molecularity of the elementary step if it occurs as shown?

Accepted Answer

Termolecular

Question 9

Refer to the ninth image. Why do only some collisions lead to a reaction?

Accepted Answer

Only collisions with correct orientation and sufficient energy are effective

Question 10

Using the table of rate laws for elementary steps (tenth image), what is the rate law for the elementary step $A + B \rightarrow$ products?

Accepted Answer

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

Question 11

According to the energy diagram for catalyzed and uncatalyzed pathways (eleventh image), what is the effect of a catalyst on a reaction?

Accepted Answer

It lowers the activation energy

Question 12

Refer to the enzyme mechanism diagram (twelfth image). What is the role of the enzyme in the reaction?

Accepted Answer

It provides an active site that orients the substrate for reaction

Question 13

In the sucrose hydrolysis reaction (thirteenth image), what is the function of the enzyme sucrase?

Accepted Answer

It strains and weakens the bond to be broken in sucrose

Question 14

Based on the fourteenth image, what happens to the enzyme after the reaction is complete?

Accepted Answer

It is unchanged and can catalyze another reaction

Question 15

A reaction is found to be first order with a half-life of 100 s. How long will it take for the concentration to decrease to 1/8 of its original value?

Accepted Answer

300 s

Question 16

If the rate law for a reaction is $	ext{Rate} = k[A]^2$, what will happen to the rate if $[A]$ is doubled?

Accepted Answer

The rate will increase by a factor of 4

Question 17

Given the Arrhenius equation $k = Ae^{-E_a/(RT)}$, what effect does increasing the activation energy $E_a$ have on the rate constant $k$?

Accepted Answer

It decreases $k$

Question 18

Which of the following best describes a reaction intermediate?

Accepted Answer

A species produced in one step and consumed in a later step

Question 19

Which of the following statements about catalysts is correct?

Accepted Answer

They provide an alternative pathway with lower activation energy

Question 20

If a reaction is zero order with respect to a reactant, what happens to the rate when the concentration of that reactant is doubled?

Accepted Answer

The rate remains unchanged

Chapter 14: Chemical Kinetics – Study Notes

Study Guide - Practice Questions

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