Deck 14: Chemical Kinetics: Reactions in the Air We Breathe

Question 1

At what time of day are ozone concentrations highest during a photochemical smog event?

A) in the morning before rush hour
B) in the morning just after rush hour
C) midmorning
D) noon
E) midafternoon

Answer 1

midafternoon

Question 2

For the reaction 2A + 3B $\rightarrow$ 4C + 5D, the rate of the reaction in terms of $\Delta$ A would be written as ________

A) - $\Delta$ 0A/ $\Delta$ t.
B) -1/2 $\Delta$ A/ $\Delta$ t.
C) + $\Delta$ A/ $\Delta$ t.
D) +1/2 $\Delta$ A/ $\Delta$ t.
E) -2 $\Delta$ A/ $\Delta$ t.

Answer 2

-1/2 $\Delta$ A/ $\Delta$ t.

Question 3

One reaction that occurs in an automobile catalytic converter is the conversion of nitrogen monoxide to nitrogen and oxygen. How is the rate of this reaction related to the rate at which the concentration of a reactant or product changes?
2NO(g) $\rightarrow$ N₂(g) + O₂(g)
I. Rate = $\Delta$ [NO]/ $\Delta$ t
II. Rate = - $\Delta$ [NO]/ $\Delta$ t
III. Rate = $\Delta$ [N₂]/ $\Delta$ t
IV. Rate = $\Delta$ [O₂]/ $\Delta$ t

A) I only
B) II only
C) III and IV only
D) I, III, and IV only
E) II, III, and IV only

Answer 3

III and IV only

Question 4

The device in automobiles that has decreased NO and partially oxidized hydrocarbons from exhaust gases is termed a ________

A) catalytic intermediate.
B) photochemical inhibitor.
C) catalytic linker.
D) nitrogen monoxide reducer.
E) catalytic converter.

Question 5

Smog created by the interaction of sunlight with nitrogen oxides and volatile organic compounds is termed ________ smog.

A) photolytic
B) photochemical
C) photophysical
D) acid
E) sulfurous

Question 6

The difference between an average rate and an instantaneous rate is ________

A) the average rate is taken over a longer time period.
B) the instantaneous rate is taken from the slope of the curve at a specific time.
C) They are not different if the time interval chosen is small enough.
D) All of the above are correct.

Question 7

For the reaction 2A + 3B $\rightarrow$ 4C + 5D, the rate of the reaction in terms of $\Delta$ C would be written as ________

A) + $\Delta$ C/ $\Delta$ t.
B) +4 $\Delta$ C/ $\Delta$ t.
C) +1/4 $\Delta$ C/ $\Delta$ t.
D) -4 $\Delta$ C/ $\Delta$ t.
E) -1/4 $\Delta$ C/ $\Delta$ t.

Question 8

The greatest NO concentration is observed ________

A) in the morning before rush hour.
B) in the morning just after rush hour.
C) in midmorning.
D) at noon.
E) in midafternoon.

Question 9

Large cities often issue ozone advisories. At what time of year would an advisory be likely to occur most often?

A) winter
B) spring
C) summer
D) fall
E) No season should have more advisories than another.

Question 10

When one chemical is a precursor of another chemical in a series of reactions, the concentrations of the two species are said to be ________

A) catalytic.
B) volatile.
C) coalescent.
D) linked.
E) intermediate.

Question 11

For the reaction 2A + 3B $\rightarrow$ 4C + 5D, the rate of the reaction in terms of $\Delta$ B would be written as ________

A) - $\Delta$ B/ $\Delta$ t.
B) + $\Delta$ B/ $\Delta$ t.
C) -1/3 $\Delta$ B/ $\Delta$ t.
D) +1/3 $\Delta$ B/ $\Delta$ t.
E) -3 $\Delta$ B/ $\Delta$ t.

Question 12

Indicate which of the following compounds is a component of photochemical smog.

A) H₂O
B) CO₂
C) N₂O
D) O₃
E) CO

Question 13

One reaction that occurs in an automobile catalytic converter is the conversion of nitrogen monoxide to nitrogen and oxygen. How could the rate of this reaction be expressed correctly in terms of the rate at which the concentration of a reactant or product changes?
2NO(g) $\rightarrow$ N₂(g) + O₂(g)

A) Rate = $\Delta$ [NO]/ $\Delta$ t
B) Rate = - $\Delta$ [NO]/ $\Delta$ t
C) Rate = $\frac { 1 } { 2 }$
$\Delta$ [NO]/ $\Delta$ t
D) Rate = - $\frac { 1 } { 2 }$
$\Delta$ [NO]/ $\Delta$ t
E) Rate = 2 $\Delta$ [NO]/ $\Delta$ t

Question 14

NO₂ contributes to the "brown haze" associated with photochemical smog events. At what time of day is NO₂ concentration highest?

A) in the morning before rush hour
B) in the morning just after rush hour
C) midmorning
D) noon
E) midafternoon

Question 15

Which of the following is not important as a contributing factor to photochemical smog?

A) stagnant air
B) sunlight
C) lots of traffic
D) irrigation
E) cars without catalytic converters

Question 16

For the reaction 2A + 3B $\rightarrow$ 4C + 5D, the rate of the reaction in terms of $\Delta$ D would be written as ________

A) + $\Delta$ D/ $\Delta$ t.
B) +5 $\Delta$ D/ $\Delta$ t.
C) +1/5 $\Delta$ D/ $\Delta$ t.
D) -5 $\Delta$ D/ $\Delta$ t.
E) -1/5 $\Delta$ D/ $\Delta$ t.

Question 17

The order in which ozone, nitrogen monoxide, and nitrogen dioxide build up in the atmosphere over the course of the day is ________, then ________, then ________

A) NO; NO₂; O₃.
B) NO; O₃; NO₂.
C) NO₂; NO; O₃.
D) NO₂; O₃; NO.
E) O₃; NO; NO₂.

Question 18

NO₂ concentrations during photochemical smog events often have two peaks, one in the early morning (8 A.M.) and another, smaller peak around 7 P.M. The second peak is due to ________

A) NO₂ emissions produced during the evening rush hour.
B) the reaction of NO and O₃.
C) the photochemical formation of O₃.
D) automobile NO emissions reacting with oxygen.
E) All of the above.

Question 19

One reaction that occurs in an automobile catalytic converter is the conversion of nitrogen monoxide to nitrogen and oxygen. How could the rate of this reaction be expressed correctly in terms of the rate at which the concentration of a reactant or product changes?
2NO(g) $\rightarrow$ N₂(g) + O₂(g)

A) Rate = $\Delta$ [NO]/ $\Delta$ t
B) Rate = $\Delta$ [O₂]/ $\Delta$ t
C) Rate = 2 $\Delta$ [O₂]/ $\Delta$ t
D) Rate = -2 $\Delta$ [NO]/ $\Delta$ t
E) Rate = 2 $\Delta$ [NO]/ $\Delta$ t

Question 20

Indicate which of the following compounds is not a component of photochemical smog.

A) O₃
B) H₂O
C) NO₂
D) NO
E) organic molecules

Question 21

A scientist conducts an experiment to determine the rate of the following reaction:
N₂(g) + O₂(g) $\rightarrow$ 2NO(g)
If the initial concentration of NO was 0.00 M and the concentration of NO was 0.050 M after 0.100 s, what is the average rate of the reaction?

A) 0.500 M/s
B) 1.00 M/s
C) 5.00 M/s
D) 10.0 M/s
E) 0.250 M/s

Question 22

One reaction that occurs in an automobile catalytic converter is the conversion of nitrogen monoxide to nitrogen and oxygen. Which one of the following statements is correct about the rates at which the concentrations change as the reaction progresses?
2NO(g) $\rightarrow$ N₂(g) + O₂(g)

A) - $\Delta$ [NO]/ $\Delta$ t increases while $\Delta$ [N₂]/ $\Delta$ t decreases.
B) - $\Delta$ [NO]/ $\Delta$ t decreases while $\Delta$ [N₂]/ $\Delta$ t increases.
C) Both - $\Delta$ NO]/ $\Delta$ t and $\Delta$ [N₂]/ $\Delta$ t decrease.
D) Both - $\Delta$ [NO]/ $\Delta$ t and $\Delta$ [N₂]/ $\Delta$ t increase.
E) The relationship between $\Delta$ [NO]/ $\Delta$ t and $\Delta$ [N₂]/ $\Delta$ t depends on the reaction mechanism.

Question 23

The following graph shows the kinetics curves for the reaction of oxygen with hydrogen to form water:
O₂(g) + 2H₂(g) $\rightarrow$ 2H₂O(g). Which curve is hydrogen?

A) the dashed curve
B) the gray curve
C) the black curve
D) either the gray or the black curve
E) Any of these curves could be hydrogen.

Question 24

HI dissociates to form I₂ and H₂:
2HI(g) $\rightarrow$ H₂(g) + I₂(g)
If the concentration of HI changes at a rate of -0.45 M/s, what is the rate of appearance of I₂(g)?

A) 0.90 M/s
B) 0.45 M/s
C) 0.23 M/s
D) 1.00 M/s
E) 0.13 M/s

Question 25

A scientist conducts an experiment to determine the rate of the following reaction:
N₂(g) + O₂(g) $\rightarrow$ 2NO(g)
If the initial concentration of N₂ was 0.500 M and the concentration of N₂ was 0.450 M after
0)100 s, what is the average rate of the reaction?

A) 0.500 M/s
B) 1.00 M/s
C) 5.00 M/s
D) 10.0 M/s
E) 0.250 M/s

Question 26

One reaction that occurs in an automobile catalytic converter is the conversion of carbon monoxide to carbon dioxide. How could the rate of this reaction be expressed correctly in terms of the rate at which the concentration of a reactant or product changes?
2CO(g) + O₂(g) $\rightarrow$ 2CO₂(g)

A) Rate = $\Delta$ CO]/ $\Delta$ t
B) Rate = - $\Delta$ [CO]/ $\Delta$ t
C) Rate = $\Delta$ O₂]/ $\Delta$ t
D) Rate = - $\frac { 1 } { 2 }$
$\Delta$ [CO]/ $\Delta$ t
E) Rate = 2 $\Delta$ [CO₂]/ $\Delta$ t

Question 27

The disappearance of HI in the reaction 2HI(g) $\rightarrow$ I₂(g) + H₂(g) is shown in the following figure. What is the instantaneous rate of this reaction at t = 5 s if the instantaneous rate of change of [HI] is 0.02 M/s?

A) 0.2 M/s
B) 0.01 M/s
C) 0.02 M/s
D) 0.100 M/s
E) 0.04 M/s

Question 28

One reaction that occurs in an automobile catalytic converter is the conversion of carbon monoxide to carbon dioxide. Examine the statements A-C: if one is incorrect, identify it. Otherwise, select response D or E as appropriate.
2CO(g) + O₂(g) $\rightarrow$ 2CO₂(g)

A)(- $\Delta$ CO]/ $\Delta$ t = $\Delta$ [CO₂]/ $\Delta$ t)
B) ( $\Delta$ [CO]/F $\Delta$ t = 2 $\Delta$ [O₂]/ $\Delta$ t
C)( $\Delta$ [O₂]/ $\Delta$ t = F $\Delta$ [CO₂]/ $\Delta$ t)
D)Statements A-C are all correct.
E)More than one of the statements A-C is incorrect.

Question 29

If the rate of appearance of O₂ in the reaction:
2O₃(g) $\rightarrow$ 3O₂(g)
Is 0.250 M/s over the first 5.50 s, how much oxygen will form during this time?

A) 1.38 M
B) 4.13 M
C) 0.69 M
D) 0.25 M
E) 0.46 M

Question 30

Ammonia gas (NH₃) is produced from hydrogen and nitrogen gas according to the following reaction:
3H₂(g) + N₂(g) $\rightarrow$ 2NH₃(g)
If the rate of production of ammonia is R(NH₃), what is the rate of loss of hydrogen and nitrogen gas, respectively?

A) -R(H₂) = 2/3 R(NH₃); -R(N₂) = 1/2 R(NH₃)
B) -R(H₂) = 3/2 R(NH₃); -R(N₂) = 2 R(NH₃)
C) -R(H₂) = 3/2 R(NH₃); -R(N₂) = 1/2 R(NH₃)
D) -R(H₂) = 2/3 R(NH₃); -R(N₂) = 2 R(NH₃)
E) -R(H₂) = R(NH₃); -R(N₂) = R(NH₃)

Question 31

A scientist conducts an experiment to determine the rate of NO formation in the reaction:
N₂(g) + O₂(g) $\rightarrow$ 2NO(g)
If the initial concentration of N₂ was 0.500 M and the concentration of N₂ was 0.450 M after
0)100 s, what is the average rate of NO formation?

A) 0.500 M/s
B) 1.00 M/s
C) 5.00 M/s
D) 10.0 M/s
E) 0.250 M/s

Question 32

Which of the following does the initial rate of a chemical reaction depend on?
I.Concentration of reactants
II.Concentration of products
III.Temperature

A) I
B) III
C) II
D) Both I and III
E) I, II, and III

Question 33

Which of the following statements is true about the instantaneous rate for the chemical reaction
A $\rightarrow$ B as the reaction progresses?

A) - $\Delta$ A/ $\Delta$ t increases while $\Delta$ B/ $\Delta$ t decreases
B) - $\Delta$ A/ $\Delta$ t decreases while $\Delta$ B/ $\Delta$ t increases
C) both - $\Delta$ A/ $\Delta$ t and $\Delta$ B/ $\Delta$ t decrease
D) both - $\Delta$ A/ $\Delta$ t and $\Delta$ B/ $\Delta$ t increase
E) The answer will vary depending on the reaction mechanism.

Question 34

If the rate of formation of ammonia is 0.345 M/s, what is the rate of disappearance of N₂?
N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g)

A) 0.173 M/s
B) 0.345 M/s
C) 0.690 M/s
D) 245 M/s
E) 0.518 M/s

Question 35

If the rate of the reaction:
2O₃(g) $\rightarrow$ 3O₂(g)
Is 0.250 M/s over the first 5.50 s, how much oxygen will form during this time?

A) 1.38 M
B) 4.13 M
C) 0.69 M
D) 0.25 M
E) 0.46 M

Question 36

Which of the following is not a possible graph of concentration versus time for a reactant?

A)
B)
C)
D)

Question 37

In the combustion of methane, CH₄(g) + 2 O₂(g) $\rightarrow$ CO₂(g) + 2 H₂O (g), which reactant has the greatest rate of disappearance?

A) CH₄
B) O₂
C) CO₂
D) H₂O
E) CH₄ and O₂ have the same rate of disappearance.

Question 38

Assuming that each of the following graphs has the same concentration and time axes, which has the greatest initial rate of disappearance of reactant?

A)
B)
C)
D)

Question 39

One reaction that occurs in an automobile catalytic converter is the conversion of carbon monoxide to carbon dioxide. How is the rate of this reaction related to the rate at which the concentration of a reactant or product changes?
2CO(g) + O₂(g) $\rightarrow$ 2CO₂(g)
I. Rate = $\Delta$ [CO]/ $\Delta$ t
II. Rate = - $\Delta$ [CO]/ $\Delta$ t
III. Rate = - $\Delta$ [O₂]/ $\Delta$ t
IV. Rate = $\Delta$ [CO₂]/ $\Delta$ t

A) I only
B) II only
C) III only
D) II and III only
E) II, III, and IV only

Question 40

If the rate of formation of ammonia is 0.345 M/s, what is the rate of disappearance of N₂? $$\frac { 1 } { 2 } \mathrm { H } _ { 2 } ( \mathrm {~g} ) + \frac { 3 } { 2 } \mathrm { H } _ { 2 } ( \mathrm {~g} ) \rightarrow \mathrm { NH } _ { 3 } ( g )$$

A) 0.173 M/s
B) 0.345 M/s
C) 0.690 M/s
D) 245 M/s
E) 0.518 M/s

Question 41

Which of these could be the units of the rate constant for a first-order reaction?

A) M/s
B) 1/Ms
C) 1/Ms²
D) 1/s
E) Ms

Question 42

Which of these could be the units for the rate constant in a second-order reaction?

A) M^-1 s
B) M s^-1
C) M^-1 s^-1
D) M^-2 s^-1
E) Ms

Question 43

A reaction is first order in A. If the rate constant of the reaction is 3.45 *10^-3 s^-1, what is the half-life (t_1/2) of the reaction?

A) 4.98 *10^-3 s
B) 200 s
C) 3.45 *10^-3 s
D) 100 s
E) 1.73 *10^-3 s

Question 44

Given the following data, determine the order of the reaction with respect to Cl₂.
2NO(g) + Cl₂(g) $\rightarrow$ 2NOCl(g) $\begin{array}{cccc}\text { Experiment } & {[\mathbf{N O}](\boldsymbol{M})} & {\left[\mathrm{Cl}_{\mathbf{2}}\right](\boldsymbol{M})} & \text { Rate }(\boldsymbol{M} / \mathbf{s}) \\1 & 0.0300 & 0.0100 & 3.4 \times 10^{-4} \\2 & 0.0150 & 0.0100 & 8.5 \times 10^{-5} \\3 & 0.0150 & 0.0400 & 3.4 \times 10^{-4}\end{array}$

A) first
B) second
C) third
D) fourth
E) fifth

Question 45

If the reaction 3A + B + $\frac { 1 } { 2 }$ C $\rightarrow$ 2D + E is first order overall, which of these could be the units of its rate constant, k?

A) 1/s
B) M/s
C) 1/Ms
D) 1/Ms²
E) Ms

Question 46

For the rate law Rate = k[A]^3/2[B], the partial order with respect to A is ________, the partial order with respect to B is ________, and the total order is ________.

A) $\frac { 3 } { 2 } ; 0 ; \frac { 3 } { 2 }$
B) $\frac { 3 } { 2 } ; 1 ; 1$
C) $\frac { 3 } { 2 } ; 1 ; \frac { 5 } { 2 }$
D) $\frac { 3 } { 2 } ; 1 ; \frac { 7 } { 2 }$
E) The orders cannot be determined without a chemical reaction.

Question 47

The reaction 2NO(g) + O₂(g) $\rightarrow$ 2NO₂(g) has the following rate law: Rate = k[O₂][NO]². If the concentration of NO is reduced by a factor of two, the rate will ________

A) double.
B) quadruple.
C) be reduced by one-quarter.
D) be reduced by one-half.
E) remain the same.

Question 48

Given the following data, determine the order of the reaction with respect to NO(g).
2NO(g) + Cl₂(g) $\rightarrow$ 2NOCl(g) $\begin{array}{cccc}\text { Experiment } & {[\mathrm{NO}](M)} & {\left[\mathrm{Cl}_{2}\right](M)} & \text { Rate }(\mathbf{M} / \mathrm{s}) \\1 & 0.0300 & 0.0100 & 3.4 \times 10^{-4} \\2 & 0.0150 & 0.0100 & 8.5 \times 10^{-5} \\3 & 0.0150 & 0.0400 & 3.4 \times 10^{-4}\end{array}$

A) first
B) second
C) third
D) fourth
E) fifth

Question 49

The second-order reaction A $\rightarrow$ B is found to have a rate constant of 0.978 M^-1s^-1. What is the half-life of this reaction when [A]₀ = 0.0300 M?

A) 0.0293 s
B) 0.710 s
C) 34.1 s
D) 60.1 s
E) 24.3 s

Question 50

A second-order reaction (2A $\rightarrow$ B) with a rate constant of 0.350 M^-1s^-1 is found to have a half-life of 3.45 s. What was the initial concentration of the reactant, [A]₀?

A) 0.828 M
B) 0.201 M
C) 1.00 M
D) 1.21 M
E) 0.350 M

Question 51

For the rate law Rate = k[A]^1/2[B], the partial order with respect to A is ________, the partial order with respect to B is ________, and the total order is ________.

A) $\frac { 1 } { 2 } ; 0 ; \frac { 1 } { 2 }$

B) $\frac { 1 } { 2 } ; 1 ; 1$

C) $\frac { 1 } { 2 } ; 1 ; \frac { 3 } { 2 }$

D) $\frac { 1 } { 2 } ; 1 ; \frac { 3 } { 2 }$ .

E) The orders cannot be determined without a chemical reaction.

Question 52

Given the following data, determine the order of the reaction with respect to H₂.
H₂(g) + 2ICl(g) $\rightarrow$ I₂(g) + 2HCl(g) $\begin{array}{cccc}\text { Experiment } & {\left[\mathrm{H}_{2}\right] \text { (torr) }} & \text { [ICl] (torr) } & \text { Rate }(\mathbf{M} / \mathbf{s}) \\1 & 250 & 325 & 1.34 \\2 & 250 & 81 & 0.331 \\3 & 50 & 325 & 0.266\end{array}$

A) one-half
B) second
C) first
D) third
E) three-halves

Question 53

The half-life (t_1/2) of a first-order reaction is 0.100 s. What is the rate constant?

A) 6.93 s^-1
B) 0.693 s^-1
C) 0.0693 s^-1
D) 0.144 s^-1
E) 3.01 s^-1

Question 54

For the rate law Rate = k[A][B]^3/2, the partial order with respect to A is ________, the partial order with respect to B is ________, and the total order is ________.

A) $0 ; \frac { 3 } { 2 } ; \frac { 3 } { 2 }$
B) $1 ; \frac { 3 } { 2 } ; 1$
C) $1 ; \frac { 3 } { 2 } ; \frac { 5 } { 2 }$
D) $1 ; \frac { 3 } { 2 } ; \frac { 7 } { 2 }$
E) The orders cannot be determined without a chemical reaction.

Question 55

For the rate law Rate = k[A][B]^1/2, the partial order with respect to A is ________, the partial order with respect to B is ________, and the total order is ________.

A) $0 ; \frac { 1 } { 2 } ; \frac { 1 } { 2 }$
B) $1 ; \frac { 1 } { 2 } ; 1$
C) $1 ; \frac { 1 } { 2 } ; \frac { 3 } { 2 }$
D) $1 ; \frac { 1 } { 2 } ; \frac { 5 } { 2 }$
E) The orders cannot be determined without a chemical reaction.

Question 56

The reaction
A + 2B $\rightarrow$ C
Is first order in B and A. The overall order of the reaction is ________

A) first.
B) second.
C) third.
D) zero.
E) fourth.

Question 57

Given the following data, determine the order of the reaction with respect to ICl.
H₂(g) + 2ICl(g) $\rightarrow$ I₂(g) + 2HCl(g) $\begin{array}{cccc}\text { Experiment } & {\left[\mathrm{H}_{2}\right] \text { (torr) }} & \text { [ICl] (torr) } & \text { Rate }(\boldsymbol{M} / \mathbf{s}) \\1 & 250 & 325 & 1.34 \\2 & 250 & 81 & 0.331 \\3 & 50 & 325 & 0.266\end{array}$

A) one-half
B) first
C) second
D) third
E) three-halves

Question 58

The reaction CHCl₃(g) + Cl₂(g) $\rightarrow$ CCl₄(g) + HCl(g) has the following rate law:
Rate = k[CHCl₃][Cl₂]. If the concentration of CHCl₃ is increased by a factor of five while the concentration of Cl₂ is kept the same, the rate will ________

A) double.
B) triple.
C) stay the same.
D) increase by a factor of five.
E) decrease by a factor of one-fifth.

Question 59

Given the following data, determine the rate law for the reaction
NH₄⁺(aq) + NO₂^-(aq) $\rightarrow$ N₂(g) + 2H₂O(l) $\begin{array}{cccc}\text { Experiment } & {\left[\mathrm{NH}_{4}^{+}\right](\boldsymbol{M})} & {\left[\mathrm{NO}_{2}{ }^{-}\right](\boldsymbol{M})} & \text { Rate }(\boldsymbol{M} / \mathbf{s}) \\1 & 0.2500 & 0.2500 & 1.25 \times 10^{-3} \\2 & 0.5000 & 0.2500 & 2.50 \times 10^{-3} \\3 & 0.2500 & 0.1250 & 6.25 \times 10^{-4}\end{array}$

A) k[NH₄⁺][NO₂^-]
B) k[NH₄⁺]²[NO₂^-]
C) k[NH₄⁺][NO₂^-]^1/2
D) k[NH₄⁺]^1/2[NO₂^-]²
E) k[NH₄⁺][NO₂^-]²

Question 60

In a rate law, the partial orders are determined by ________

A) the reactant concentrations.
B) the stoichiometric coefficients.
C) the product concentrations.
D) experiment.
E) the difference between the forward and reverse rates.

Question 61

The initial rate data for the reaction 2N₂O₅(g) $\rightarrow$ 4NO₂(g) + O₂(g) is shown in the following table. Determine the value of the rate constant for this reaction. $$\begin{array} { c l l } \text { Experiment } & { \left[ \mathrm { N } _ { 2 } \mathrm { O } _ { \mathbf { 5 } } \right] ( \boldsymbol { M } ) } & \text { Rate } ( \boldsymbol { M } / \mathrm { s } ) \\1 & 2.56 \times 10 ^ { 3 } & 450 \\2 & 1.28 \times 10 ^ { 2 } & 22.5\end{array}$$

A) 4.09 s^-1
B) 0.176 s^-1
C) 0.0569 s^-1
D) 0.225 s^-1
E) 80.1 s^-1

Question 62

Determine the overall order of the reaction H₂(g) + 2ICl(g) $\rightarrow$ I₂(g) + 2HCl(g) from the following data: $\begin{array} { c c c c }\text { Experiment } && P_{\text {PCI }} \text { (torr) } & \text { Rate (torr/s) }\\ & P _ { \mathbf { H } _ { \mathbf { 2 } } } & & \\ & \text { (torr) } & & \\ 1 & 250 & 325 & 1.34 \\ 2 & 250 & 81 & 0.331 \\ 3 & 50 & 325 & 0.266 \end{array}$

A) first
B) second
C) third
D) fourth
E) zero

Question 63

Determine the order of the reaction CH₃CHO (g) $\rightarrow$ CH₄(g) + CO(g) from the following data: $\begin{array} { c c c } \text { Experiment }&&\text { Rate (mtorr/s) }\\& \boldsymbol { P } _ { \left( \mathrm { CH } _ { 3 } \mathbf { C H O } \right) } \\ & \text { (mtorr) } & \\ 1 & 25.0 & 45.6 \\ 2 & 12.5 & 16.0 \end{array}$

A) one-half
B) first
C) second
D) three-halves
E) third

Question 64

Indicate which of the following plots would be obtained for a second-order reaction.

A)
B)
C)
D)

Question 65

Given the following data, determine the rate law for the reaction
H₂(g) + 2ICl(g) $\rightarrow$ I₂(g) + 2HCl(g) $\begin{array}{cccc}\text { Experiment } & {\left[\mathrm{H}_{2}\right] \text { (torr) }} & \text { [ICl] (torr) } & \text { Rate } \text { (torr/s) } \\1 & 250 & 325 & 1.34 \\2 & 250 & 81 & 0.331 \\3 & 50 & 325 & 0.266\end{array}$

A) Rate = k[H₂][ICl]
B) Rate = k[H₂][ICl]²
C) Rate = k[H₂]²[ICl]
D) Rate = k[H₂]^1/2[ICl]^1/2
E) Rate = k[H₂][ICl]^1/2

Question 66

Chlorine dioxide (ClO₂) is used as a disinfectant in municipal water-treatment plants. It decomposes in a first-order reaction with a rate constant of 14 s^-1. How long would it take for an initial concentration of 0.06 M to decrease to 0.02 M?

A) 13 ms
B) 78 ms
C) 92 ms
D) 146 ms
E) 239 ms

Question 67

Chlorine dioxide (ClO₂) is used as a disinfectant in municipal water-treatment plants. It decomposes in a first-order reaction with a rate constant of 0.0714 s^-1. If the initial concentration were 0.12 M, what would the concentration be after 14.0 s has elapsed?

A) 0.033 M
B) 0.12 M
C) 0.060 M
D) 0.012 M
E) 0.044 M

Question 68

Given the following data, determine the rate constant of the reaction
2NO(g) + Cl₂(g) $\rightarrow$ 2NOCl(g) $$\begin{array} { c c c c } \text { Experiment } & { [ \mathbf { N O } ] ( \boldsymbol { M } ) } & { \left[ \mathrm { Ch } _ { 2 } \right] ( \boldsymbol { M } ) } & \text { Rate } ( \boldsymbol { M } / \mathrm { s } ) \\1 & 0.0300 & 0.0100 & 3.4 \times 10 ^ { - 4 } \\2 & 0.0150 & 0.0100 & 8.5 \times 10 ^ { - 5 } \\3 & 0.0150 & 0.0400 & 3.4 \times 10 ^ { - 4 }\end{array}$$

A) 1.13 M^-2 s^-1
B) 9.44 M^-2 s^-1
C) 37.8 M^-2 s^-1
D) 0.0265 M^-2 s^-1
E) 59.6 M^-2 s^-1

Question 69

The second-order reaction A + B $\rightarrow$ C will obey pseudo-first-order kinetics when ________

A) the concentrations of A and B are both small.
B) the concentration of one of the reactants does not change.
C) the concentration of C is large.
D) the concentrations of A and B are both large.
E) a catalyst changes the mechanism to a first-order reaction.

Question 70

Determine the overall order of the reaction 2NO(g) + Cl₂(g) $\rightarrow$ 2NOCl(g) from the following data: $\begin{array}{cccc}\text { Experiment } & {[\mathbf{N O}](M)} & {\left[\mathrm{Cl}_{2}\right](M)} & \text { Rate }(M / \mathbf{s}) \\1 & 0.0300 & 0.0100 & 3.4 \times 10^{-4} \\2 & 0.0150 & 0.0100 & 8.5 \times 10^{-5} \\3 & 0.0150 & 0.0400 & 3.4 \times 10^{-4}\end{array}$

A) first
B) second
C) third
D) fourth
E) fifth

Question 71

Given the following data, determine the rate law for the reaction
2NO(g) + Cl₂(g) $\rightarrow$ 2NOCl(g) $\begin{array}{cccc}\text { Experiment } & {[\mathrm{NO}](M)} & {[\mathbf{CI_{2}}](M)} & \text { Rate }(M / s) \\1 & 0.0300 & 0.0100 & 3.4 \times 10^{-4} \\2 & 0.0150 & 0.0100 & 8.5 \times 10^{-5} \\3 & 0.0150 & 0.0400 & 3.4 \times 10^{-4}\end{array}$

A) Rate = k[NO][Cl₂]
B) Rate = k[NO][Cl₂]²
C) Rate = k[NO]²[Cl₂]
D) Rate = k[NO]²[Cl₂]²
E) Rate = k[NO][Cl₂]^1/2

Question 72

The first-order reaction A $\rightarrow$ B, has k = 5.67 s^-1. If [A]₀ = 0.500 M, how long will it take to reach [A] = 0.124 M?

A) 0.122 s
B) 0.100 s
C) 8.18 s
D) 0.246 s
E) 0.488 s

Question 73

Which of the following plots indicates that the reaction is zero order?

A)
B)
C)
D)

Question 74

The linear form of ________ is very useful, as it allows us to calculate the activation energy and the frequency factor.

A) the Boltzmann equation
B) the Arrhenius equation
C) Planck's equation
D) the rate law
E) the integrated rate law

Question 75

Given the following data, determine the rate constant, k, of the reaction
H₂(g) + 2ICl(g) $\rightarrow$ I₂(g) + 2HCl(g) $$\begin{array} { c c c c } \text { Experiment } & { \left[ \mathbf { H } _ { 2 } \right] \text { (torr) } } & { [ \text { ICl] (torr) } } & \text { Rate } \text { (torr/s) } \\1 & 250 & 325 & 1.34 \\2 & 250 & 81 & 0.331 \\3 & 50 & 325 & 0.266\end{array}$$

A) 1.65 *10^-5 torr ^-1s^-1
B) 6.06 *10⁴ torr ^-1s^-1
C) 8.17 *10^-5 torr ^-1s^-1
D) 1.34 torr ^-1s^-1
E) 3.48 *10³ torr ^-1s^-1

Question 76

Which of the following plots would indicate that a reaction was first order?

A)
B)
C)
D)

Question 77

Given the following data, determine the rate law for the reaction
CH₃CHO(g) $\rightarrow$ CH₄(g) + CO(g) $\begin{array} { l } \text {Experiment }&\boldsymbol{P}_{\left(\mathrm{CH}_{3} \mathrm{CHO}\right)}&\text { Rate (mtorr/s) }\\&\text { (mtorr) }\\1 & 25.0 & 45.6 \\2 & 12.5 & 16.0\end{array}$

A) Rate = k
B) Rate = kP[CH₃CHO]
C) Rate = kP[CH₃CHO]^3/2
D) Rate = kP[CH₃CHO]^1/2
E) Rate = kP[CH₃CHO]²

Question 78

Collision theory assumes that the rate of a reaction depends on ________

A) the energy of collisions.
B) the orientation of colliding molecules.
C) the energy of collisions and the orientation of colliding molecules.
D) the change in energy between the products and the reactants.
E) the change in free energy between the reactants and products.

Question 79

Which of the following plots indicates that the reaction is second order?

A)
B)
C)
D)

Question 80

Indicate which of the following plots would be obtained for a first-order reaction.

A)
B)
C)
D)