Q: For the reaction $$2\text{NO}_2(g) + \text{F}_2(g) \rightarrow 2\text{NO}_2\text{F}(g)$$, the rate law is found to be $$\text{Rate} = k[\text{NO}_2][\text{F}_2]. $$What is the order of the reaction with respect to $$\text{NO}_2$$ and the overall order?

First order in $$\text{NO}_2$$, first order in $$\text{F}_2$$, second order overall

Q: For the elementary step $$\text{Cl} + \text{CO} \rightarrow \text{ClCO}$$, what is the rate law?

$$\text{Rate} = k[\text{Cl}][\text{CO}]$$

Question 1

Which of the following best describes the rate of a chemical reaction?

Accepted Answer

The change in concentration of a reactant or product per unit time

Question 2

For the reaction $$2	ext{NO}_2(g) + 	ext{F}_2(g) ightarrow 2	ext{NO}_2	ext{F}(g)$$, the rate law is found to be $$	ext{Rate} = k[	ext{NO}_2][	ext{F}_2]. $$What is the order of the reaction with respect to $$	ext{NO}_2$$ and the overall order?

Accepted Answer

First order in $$	ext{NO}_2$$, first order in $$	ext{F}_2$$, second order overall

Question 3

A reaction is found to be first order in $$A. If $$the initial concentration of $$A is $$doubled, what happens to the rate of the reaction?

Accepted Answer

It doubles

Question 4

Given the data for the reaction $$A \rightarrow B$$:

| [A] (M) | Initial Rate (M/s) |
|---------|-------------------|
| 0.10    | 0.020             |
| 0.20    | 0.080             |

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

Accepted Answer

Second order

Question 5

The rate law for a reaction is $$	ext{Rate} = k[	ext{A}]^2[	ext{B}]^0. If $$the concentration of $$	ext{A} is $$tripled and $$	ext{B} is $$doubled, by what factor does the rate increase?

Accepted Answer

9

Question 6

Which of the following statements about the half-life of a first-order reaction is correct?

Accepted Answer

It is constant and independent of the initial concentration

Question 7

A first-order reaction has a rate constant $$k = 0.693\ 	ext{min}^{-1}. $$What is the half-life of the reaction?

Accepted Answer

$$1.00\ 	ext{min}$$

Question 8

For a reaction with the rate law $$	ext{Rate} = k[	ext{A}]$$, which of the following plots will yield a straight line?

Accepted Answer

$$\ln[	ext{A}] vs. $$time

Question 9

The decomposition of $$	ext{SO}_2	ext{Cl}_2 is $$first order with $$k = 2.90 	imes 10$$^{-4}$$\ 	ext{s}^{-1}. If $$the initial concentration is $$0.0225\ 	ext{M}$$, what is the concentration after $$865\ 	ext{s}$$? (Use $$\ln[	ext{A}]_t = -kt + \ln[	ext{A}]_0)$$

Accepted Answer

$$0.0176\ 	ext{M}$$

Question 10

Which factor does NOT generally increase the rate of a chemical reaction?

Accepted Answer

Decreasing the surface area of a solid reactant

Question 11

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 12

A reaction has a rate constant of $$0.0117\ 	ext{s}^{-1} at$$ $$400\ 	ext{K}$$ and $$0.689\ 	ext{s}^{-1} at$$ $$450\ 	ext{K}. $$Using the two-point Arrhenius equation, what is the activation energy $$E_a (in kJ/$$mol)? ($$R = 8.314\ 	ext{J}\cdot	ext{mol}^{-1}\cdot	ext{K}^{-1})$$

Accepted Answer

$$98.7\ 	ext{kJ/mol}$$

Question 13

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

Accepted Answer

A greater fraction of molecules have enough thermal energy to surmount the activation barrier

Question 14

In a reaction mechanism, what is the rate-determining step?

Accepted Answer

The slowest step in the mechanism

Question 15

Which of the following statements about catalysts is FALSE?

Accepted Answer

A catalyst is consumed in the reaction and not regenerated

Question 16

For the elementary step $$	ext{Cl} + 	ext{CO} ightarrow 	ext{ClCO}$$, what is the rate law?

Accepted Answer

$$	ext{Rate} = k[	ext{Cl}][	ext{CO}]$$

Question 17

A reaction is second order in $$A$$ and zero order in $$B. If$$ $$[A] is $$doubled and $$[B] is $$tripled, how does the rate change?

Accepted Answer

It increases by a factor of 4

Question 18

Which of the following is a correct statement about reaction intermediates?

Accepted Answer

They are formed in one step and consumed in a later step of the mechanism

Question 19

A plot of $$1/[A]$$ versus time yields a straight line for a reaction. What is the order of the reaction?

Accepted Answer

Second order

Chemical Kinetics: Reaction Rates and Factors Affecting Rate

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