Q: For the reaction $$2\text{HI}(g) \rightarrow \text{H}_2(g) + \text{I}_2(g)$$, which expression correctly relates the rate of disappearance of HI to the rate of appearance of $$\text{I}_2$$?

$$\text{Rate} = -\frac{1}{2} \frac{\Delta[\text{HI}]}{\Delta t} = \frac{\Delta[\text{I}_2]}{\Delta t}$$

Q: The decomposition of $$\text{N}_2\text{O}_5 is $$described by the equation $$2\text{N}_2\text{O}_5(g) \rightarrow 4\text{NO}_2(g) + \text{O}_2(g). If $$the rate of disappearance of $$\text{N}_2\text{O}_5 is$$ $$4.2 \times 10$$^{-7}$$ \text{M/s}$$, what is the rate of appearance of $$\text{NO}_2$$?

$$8.4 \times 10$$^{-7}$$ \text{M/s}$$

Question 1

Which of the following statements best describes the role of a catalyst in a chemical reaction?

Accepted Answer

A catalyst speeds up a reaction by providing an alternative mechanism with a lower activation energy.

Question 2

For the reaction $$2	ext{HI}(g) ightarrow 	ext{H}_2(g) + 	ext{I}_2(g)$$, which expression correctly relates the rate of disappearance of HI to the rate of appearance of $$	ext{I}_2$$?

Accepted Answer

$$	ext{Rate} = -\frac{1}{2} \frac{\Delta[	ext{HI}]}{\Delta t} = \frac{\Delta[	ext{I}_2]}{\Delta t}$$

Question 3

A reaction is found to be first-order in A and second-order in B. Which is the correct rate law for this reaction?

Accepted Answer

$$	ext{Rate} = k[A][B]^2$$

Question 4

Which of the following will NOT increase the rate of a chemical reaction?

Accepted Answer

Decreasing the surface area of a solid reactant

Question 5

For a first-order reaction, which of the following plots will yield a straight line?

Accepted Answer

A plot of $$\ln[A]$$ versus $$t$$

Question 6

The decomposition of $$	ext{N}_2	ext{O}_5 is $$described by the equation $$2	ext{N}_2	ext{O}_5(g) ightarrow 4	ext{NO}_2(g) + 	ext{O}_2(g). If $$the rate of disappearance of $$	ext{N}_2	ext{O}_5 is$$ $$4.2 	imes 10$$^{-7}$$ 	ext{M/s}$$, what is the rate of appearance of $$	ext{NO}_2$$?

Accepted Answer

$$8.4 	imes 10$$^{-7}$$ 	ext{M/s}$$

Question 7

Which of the following statements about reaction order is correct?

Accepted Answer

The reaction order is determined experimentally.

Question 8

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

Accepted Answer

6

Question 9

For a second-order reaction with respect to A, which integrated rate law is correct?

Accepted Answer

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

Question 10

Which of the following best explains why a powdered solid reacts faster than a single large piece of the same solid?

Accepted Answer

The powdered solid has a greater surface area, allowing more collisions with reactant molecules.

Question 11

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

Accepted Answer

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

Question 12

A supersaturated solution is best described as:

Accepted Answer

A solution that contains more dissolved solute than it would at equilibrium.

Question 13

Which of the following is true about the rate constant $$k in a $$rate law?

Accepted Answer

The units of $$k$$ depend on the overall order of the reaction.

Question 14

If a reaction is first-order in A, what is the effect on the rate if the concentration of A is tripled?

Accepted Answer

The rate triples.

Question 15

Which of the following is a correct statement about the initial rate of a reaction?

Accepted Answer

It is the instantaneous rate at the beginning of the reaction.

Question 16

A reaction has the rate law $$	ext{Rate} = k[A]^2. If$$ $$[A]_0 = 0.10\ 	ext{M}$$ and $$k = 0.50\ 	ext{M}^{-1}	ext{s}^{-1}$$, what is the half-life of the reaction?

Accepted Answer

$$t_{1/2} = \frac{1}{k[A]_0} = \frac{1}{0.50 	imes 0.10} = 20\ 	ext{s}$$

Question 17

Which of the following best describes why dust explosions are more dangerous than explosions involving large solid pieces of the same material?

Accepted Answer

Dust particles have a much greater surface area, leading to a much faster reaction rate.

Question 18

Which of the following is NOT a factor that affects the rate of a chemical reaction?

Accepted Answer

The concentration of the products

Question 19

For the reaction $$	ext{C}_4	ext{H}_9	ext{Cl}(aq) + 	ext{H}_2	ext{O}(l) ightarrow 	ext{C}_4	ext{H}_9	ext{OH}(aq) + 	ext{HCl}(aq)$$, if the rate of disappearance of $$	ext{C}_4	ext{H}_9	ext{Cl} is$$ $$2.0 	imes 10$$^{-4}$$\ 	ext{M/s}$$, what is the rate of appearance of $$	ext{C}_4	ext{H}_9	ext{OH}$$?

Accepted Answer

$$2.0 	imes 10$$^{-4}$$\ 	ext{M/s}$$

Chapter 14: Chemical Kinetics – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards