Question 1

If tripling the concentration of reactant A increases the rate of a reaction by a factor of nine, what is the order of the reaction with respect to A?

Accepted Answer

Second order

Question 2

For the reaction $$2NO(g) + Br_2$(g) ightarrow 2NOBr(g)$$, the experimentally determined rate law is $$	ext{rate} = k[NO]^2[Br_2$]. $$What are the units of the rate constant $$k$$?

Accepted Answer

$$M^{-2}$$ $$s^{-1}$$

Question 3

Given the reaction $$2NO(g) + Br_2$(g) ightarrow 2NOBr(g)$$ and the rate law $$	ext{rate} = k[NO]^2[Br_2$]$$, how is the rate of appearance of NOBr related to the rate of disappearance of Br$$_2$$?

Accepted Answer

$$\frac{d[NOBr]}{dt} = 2 \frac{d[Br_2$]}{dt}$$

Question 4

A reaction has the rate law $$	ext{rate} = k[A]. $$Which of the following is the correct integrated rate law for this first-order reaction?

Accepted Answer

$$\ln[A] = -kt + \ln[A]_0$$

Question 5

For a zero-order reaction, which plot will yield a straight line?

Accepted Answer

$$[A] vs$$. $$t$$

Question 6

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

Accepted Answer

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

Question 7

For the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, if $$[NO] = 0.075\ M$$ and $$[Br_2$] = 0.25\ M$$, and $$k = 12000\ M$$^{-2}$$s^{-1}$$, what is the rate of disappearance of Br$$_2$?

Accepted Answer

$$16.8\ M/s$$

Question 8

Which of the following statements about reaction order is correct?

Accepted Answer

Reaction order is always determined experimentally.

Question 9

A student monitors the decomposition of NO$$_2 at 300$$°C and plots $$\frac{1}{[NO_2$]} vs. $$time. The plot is linear. What is the order of the reaction?

Accepted Answer

Second order

Question 10

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

Accepted Answer

It is independent of the initial concentration.

Question 11

For the reaction $$2NO(g) + 2H_2(g) ightarrow N_2$(g) + 2H_2O(g)$$, if the rate law is $$	ext{rate} = k[NO]^2[H_2$]$$, what is the overall order of the reaction?

Accepted Answer

Third order

Question 12

A zero-order reaction has an initial concentration $$[A]_0 = 0.50\ M$$ and $$k = 0.10\ M/s. $$How long will it take for $$[A] to $$reach $$0.10\ M$$?

Accepted Answer

$$4\ s$$

Question 13

Which of the following is a typical scenario where a zero-order reaction is observed?

Accepted Answer

Decomposition of a precursor on a saturated catalyst

Question 14

For a second-order reaction, which integrated rate law is correct?

Accepted Answer

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

Question 15

A first-order reaction has a rate constant $$k = 0.010\ s$$^{-1}$$. What is its half-life?

Accepted Answer

$$69.3\ s$$

Question 16

In a reaction, doubling the concentration of reactant B causes the rate to quadruple. What is the order of the reaction with respect to B?

Accepted Answer

Second order

Question 17

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

Accepted Answer

The rate at a specific moment, determined by the tangent to the concentration vs. time curve

Question 18

For the reaction $$A + 2B ightarrow 3C$$, the rate law is $$	ext{rate} = k[A][B]^2. If$$ $$[A] is $$doubled and $$[B] is $$tripled, by what factor does the rate increase?

Accepted Answer

18

Question 19

Which of the following is NOT a correct statement about the rate constant $$k$$?

Accepted Answer

It depends on the concentration of reactants.

Question 20

In the reaction $$2NO(g) + Br_2$(g) \rightarrow 2NOBr(g)$$, what is the rate law if the initial rate does not change when $$[Br_2$] is $$doubled, but increases fourfold when $$[NO] is $$doubled?

Accepted Answer

$$	ext{rate} = k[NO]^2$$

Chemical Kinetics: Rate Laws, Reaction Orders, and Integrated Rate Laws

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