Deck 12: Chemical Kinetics

Question 1

Which statement is true for the general rate law: Rate = k[A]^m[B]ⁿ?

A)It can be written from the stoichiometry of the overall reaction.
B)The overall order of the reaction is equal to m times n.
C)The values for the exponents must be determined by experiment.
D)The exponents in the rate law must be positive integers.

Answer 1

The values for the exponents must be determined by experiment.

Question 2

For the reaction shown below,what is the relationship between the rate of formation of Br₂ and the rate of reaction of Br^- over the same time period?
ClO₂^-(aq)+ 4 Br^-(aq)+ 4 H⁺(aq)→ Cl^-(aq)+ 2 Br₂(aq)+2 H₂O(l)

A)rate of formation of Br₂ = 1/2 × rate of reaction of Br^-
B)rate of formation of Br₂ = 1/4 × rate of reaction of Br^-
C)rate of formation of Br₂ = 2 × rate of reaction of Br^-
D)Rate of formation of Br₂ = 2 × rate of reaction of Br^-

Answer 2

rate of formation of Br₂ = 1/2 × rate of reaction of Br^-

Question 3

For the reaction shown below,what is the order of reaction with respect to Br^-?
ClO₂^-(aq)+ 4 Br^-(aq)+ 4 H⁺(aq)→ Cl^-(aq)+ 2 Br₂(aq)+2 H₂O(l)

A)1^st order
B)2^nd order
C)4^th order
D)can't tell from the information provided

Answer 3

can't tell from the information provided

Question 4

The reaction below is first order in H₂ and second order in NO.What is the rate law for this reaction?
2 H₂(g)+ 2 NO(g)→ N₂(g)+ 2 H₂O(g)

A)Rate = 2k[H₂][NO]
B)Rate = k[H₂][NO]²
C)Rate = k[H₂]²[NO]²
D)Rate = 2k[H₂]²[NO]²

Question 5

"Instantaneous rate" is defined as the

A)change in concentration per unit time.
B)equation showing how the rate depends on the concentration of each reactant.
C)rate of reaction at a particular time.
D)rate of reaction during a time interval.

Question 6

A concentration-time study of the gas phase reaction 2 A₃ → 3 A₂ produced the data in the table below.
Time (s)[A₃] (M)[A₂] (M)
0 4)00 × 10^-4 0
10 2.00 × 10^-4 3.00 × 10^-4
20 1.00 × 10^-4 4.50 × 10^-4
30 5.00 × 10^-5 ?
What is the average rate of formation of A₂ in the time interval 20-30 seconds?

A)6)00 × 10^-4 M/s
B)5)25 × 10^-5 M/s
C)7)50 × 10^-6 M/s
D)6)00 × 10^-6 M/s

Question 7

Hydroquinone,HOC₆H₆OH,can be formed by the reaction with acetylene below:
2 HCCH + 3 CO + H₂O → HOC₆H₄OH + CO₂
How is the rate of disappearance of acetylene,HCCH,related to the appearance of hydroquinone (Hq)?
= ?

A)
B)
C)
D)

Question 8

The decomposition of dinitrogen pentoxide is described by the chemical equation
2 N₂O₅(g)→ 4 NO₂(g)+ O₂(g)
If the rate of appearance of O₂ is equal to 2.40 mol/min at a particular moment,what is the rate of disappearance of N₂O₅ at that moment?

A)0)600 mol/min
B)1)20 mol/min
C)4)80 mol/min
D)9)60 mol/min

Question 9

The decomposition of dinitrogen pentoxide is described by the chemical equation
2 N₂O₅(g)→ 4 NO₂(g)+ O₂(g)
If the rate of disappearance of N₂O₅ is equal to 1.40 mol/min at a particular moment,what is the rate of appearance of NO₂ at that moment?

A)0)700 mol/min
B)1)40 mol/min
C)2)80 mol/min
D)5)60 mol/min

Question 10

The decomposition of dinitrogen pentoxide is described by the chemical equation
2 N₂O₅(g)→ 4 NO₂(g)+ O₂(g)
If the rate of appearance of NO₂ is equal to 0.560 mol/min at a particular moment,what is the rate of appearance of O₂ at that moment?

A)0)140 mol/min
B)0)280 mol/min
C)1)12 mol/min
D)2)24 mol/min

Question 11

For a reaction that follows the general rate law,Rate = k[A][B]²,what will happen to the rate of reaction if the concentration of B is increased by a factor of 2.00? The rate will

A)decrease by a factor of 1/4.00.
B)decrease by a factor of 1/2.00.
C)increase by a factor of 2.00.
D)increase by a factor of 4.00.

Question 12

Molecular hydrogen can be made from methane gas by the reaction below.How is the rate of disappearance of CH₄ related to the rate of appearance of H₂?
= ?
CH₄ (g)+ H₂O (l)→ CO (g)+ 3H₂ (g)

A)
B)
C)
D)none of these

Question 13

The reaction shown below has the rate law: Rate = k[BrO₃^-][Br^-][H⁺]².
BrO₃^-(aq)+ 5 Br^-(aq)+ 6 H⁺(aq)→ 3 Br₂(aq)+ 3 H₂O(l)
What is the overall order of reaction?

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

Question 14

The reaction that occurs in a Breathalyzer,a device used to determine the alcohol level in a person's bloodstream,is given below.If the rate of appearance of Cr₂(SO₄)₃ is 1.24 mol/min at a particular moment,what is the rate of disappearance of C₂H₆O at that moment?

A)0)413 mol/min
B)0)826 mol/min
C)1)86 mol/min
D)3)72 mol/min

Question 15

A concentration-time study of the gas phase reaction 2 A₃ → 3 A₂ produced the data in the table below.
Time (s)[A₃] (M)[A₂] (M)
0 4)00 × 10^-4 0
10 2.00 × 10^-4 3.00 × 10^-4
20 1.00 × 10^-4 4.50 × 10^-4
30 5.00 × 10^-5 ?
What is the average rate of decomposition of A₃ in the time interval 20-30 seconds?

A)4)00 × 10^-4 M/s
B)3)50 × 10^-5 M/s
C)5)00 × 10^-6 M/s
D)4)00 × 10^-6 M/s

Question 16

For a reaction that follows the general rate law,Rate = k[A][B]²,what will happen to the rate of reaction if the concentration of A is increased by a factor of 3.00? The rate will

A)decrease by a factor of 1/9.00.
B)decrease by a factor of 1/3.00.
C)increase by a factor of 3.00.
D)increase by a factor of 9.00.

Question 17

Which term describes the measure of the increase in the concentration of a product per unit time?

A)activation energy
B)kinetics
C)reaction rate
D)reaction time

Question 18

A concentration-time study of the gas phase reaction 2 A₃ → 3 A₂ produced the data in the table below.
Time (s)[A₃] (M)[A₂] (M)
0 4)00 × 10^-4 0
10 2.00 × 10^-4 3.00 × 10^-4
20 1.00 × 10^-4 4.50 × 10^-4
30 5.00 × 10^-5 ?
What is the concentration of A₂ after 30 seconds?

A)5)00 × 10^-4 M
B)5)25 × 10^-4 M
C)5)50 × 10^-4 M
D)6)00 × 10^-4 M

Question 19

Methanol can be produced by the following reaction:
CO(g)+ 2 H₂(g)→ CH₃OH(g).
How is the rate of disappearance of hydrogen gas related to the rate of appearance of methanol?
= ?

A)
B)
C)
D)none of these

Question 20

Hydrogen peroxide decomposes to water and oxygen according to the reaction below:
2 H₂O₂(aq)→ 2 H₂O(l)+ O₂(g)
In the presence of large excesses of I^- ion,the following set of data is obtained.What is the average rate of disappearance of H₂O₂(aq)in M/s in the first 45.0 seconds of the reaction if 1.00 L of H₂O₂ reacts at 25°C and 1.00 atm pressure?

A)9)09 × 10^-7 M/s
B)3)63 × 10^-6 M/s
C)4)33 × 10^-5 M/s
D)1)64 × 10^-4 M/s

Question 21

The following set of data was obtained by the method of initial rates for the reaction:
2 HgCl₂(aq)+ C₂O₄^2-(aq)→ 2 Cl^-(aq)+ 2 CO₂(g)+ Hg₂Cl₂(s)
What is the rate law for the reaction?

A)Rate = k[HgCl₂][C₂O₄^2-]^-2
B)Rate = k[HgCl₂][C₂O₄^2-]^-1
C)Rate = k[HgCl₂]²[C₂O₄^2-]
D)Rate = k[HgCl₂][C₂O₄^2-]²

Question 22

The following set of data was obtained by the method of initial rates for the reaction:
S₂O₈^2-(aq)+ 3 I^-(aq)→ 2 SO₄^2-(aq)+ I₃^-(aq)
What is the rate law for the reaction?

A)Rate = k[S₂O₈^2-][I^-]
B)Rate = k[S₂O₈^2-][I^-]⁵
C)Rate = k[S₂O₈^2-][I^-]²
D)Rate = k[S₂O₈^2-]²[I^-]

Question 23

The decomposition of ammonia to nitrogen and hydrogen on a tungsten filament at 800°C is independent of the concentration of ammonia at high pressures of ammonia.What is the order of the reaction with respect to ammonia?

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

Question 24

The reaction between chlorine and nitric oxide to form nitrosyl chloride is shown below.If the reaction rate doubles when the concentration of Cl₂ is doubled and the rate quadruples when the concentration of NO is doubled,by what factor will the rate increase if both concentrations,NO and Cl₂,are doubled?
Cl₂(g)+ 2 NO(g)→ 2 NOCl(g)

A)2
B)4
C)8
D)16

Question 25

Chlorine reacts with chloroform according to the reaction given below:
Cl₂ + CHCl₃ → CCl₄ + HCl
When the initial concentration of Cl₂ is doubled the reaction rate increases by a factor of 1.41.What is the order of the reaction with respect to Cl₂?

A)-1/2
B)-1
C)1/2
D)2

Question 26

The following set of data was obtained by the method of initial rates for the reaction:
(H₃C)₃CBr + OH^- → (H₃C)₃COH + Br^-
What is the order of reaction with respect to ion,OH^-?

A)zero
B)first
C)second
D)none of these

Question 27

The following set of data was obtained by the method of initial rates for the reaction:
S₂O₈^2-(aq)+ 3 I^-(aq)→ 2 SO₄^2-(aq)+ I₃^-(aq)
What is the initial rate when S₂O₈^2- is 0.15 M and I^- is 0.15 M?

A)4)10 × 10^-6 M s^-1
B)8)10 × 10^-3 M s^-1
C)1)22 × 10^-2 M s^-1
D)5)40 × 10^-2 M s^-1

Question 28

Given the following hypothetical reaction: 2 E(g)+ F(g)+ G(g)→ products.
If the rate law is: Rate = k[E]²[F]^-1,what is the overall order of reaction?

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

Question 29

Using the method of initial rates for the reaction A → B,if the initial concentration of A is doubled and the rate of reaction quadruples,what is the order of reaction with respect to A?

A)zeroth
B)first
C)second
D)fourth

Question 30

What is the overall reaction order for the reaction that has the rate law: Rate = k[H₂][NO]²?

A)zero order
B)first order
C)second order
D)third order

Question 31

Iodide and hypochlorite ion react in aqueous solution according to the reaction below:
I^- + OCl^- → OI^- + Cl^-
If the concentration of OH^- in the solution is doubled,the rate of the reaction is halved.What is the order of the reaction with respect to OH^-?

A)-2
B)-1
C)+1
D)+2

Question 32

The hydrolysis of tert-butyl chloride is given in the reaction below:
(CH₃)₃CCl(aq)+ H₂O(l)→ (CH₃)₃COH(aq)+ H⁺(aq)+ Cl^-(aq)
If the rate law is: Rate = k[(CH₃)₃CCl],what is the order of the reaction with respect to water?

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

Question 33

If the units for rate are M s^-1,what are the units for the rate constant,k,if the overall order of the reaction is three?

A)s^-1
B)M² s^-1
C)M^-1 s^-1
D)M^-2 s^-1

Question 34

The first-order decomposition of hydrogen peroxide occurs according to the equation
2 H₂O₂(aq)→ 2 H₂O(l)+ O₂(g)
Using data from a concentration-time study of this reaction,which plot will produce a straight line?

A)[H₂O₂] versus time
B)[H₂O₂]² versus time
C)1/[H₂O₂] versus time
D)ln[H₂O₂] versus time

Question 35

The following set of data was obtained by the method of initial rates for the reaction:
(H₃C)₃CBr + OH^- → (H₃C)₃COH + Br^-
What is the value of the rate constant,k?

A)8)8 × 10^-4 s^-1
B)4)4 × 10^-4 s^-1
C)1)8 × 10^-4 s^-1
D)none of these

Question 36

The following set of data was obtained by the method of initial rates for the reaction:
BrO₃^-(aq)+ 5 Br^-(aq)+ 6 H⁺(aq)→ 3 Br₂(aq)+ 3 H₂O(l).
Calculate the initial rate when BrO₃^- is 0.30 M,Br^- is 0.050 M,and H⁺ is 0.15 M.

A)6)1 × 10^-5 M/s
B)2)7 × 10^-3 M/s
C)5)3 × 10^-2 M/s
D)8)4 × 10^-2 M/s

Question 37

Cerium(IV)ion reacts with thallium(I)ion in a one-step reaction shown below:
2 Ce⁴⁺(aq)+ Tl⁺(aq)→ 2 Ce³⁺(aq)+ Tl³⁺(aq).
If the rate law is: Rate = k[Ce⁴⁺]²[Tl⁺],what is the overall order of the reaction?

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

Question 38

Given the following hypothetical reaction: 2 E(g)+ F(g)+ G(g)→ products.
If the rate law is: Rate = k[E]²[F]^-1,what is the order of reaction with respect to E?

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

Question 39

The following set of data was obtained by the method of initial rates for the reaction:
2 HgCl₂(aq)+ C₂O₄^2-(aq)→ 2 Cl^-(aq)+ 2 CO₂(g)+ Hg₂Cl₂(s)
What is the value of the rate constant,k?

A)1)4 × 10^-8 1/M²∙s
B)1)3 × 10^-7 1/M²∙s
C)1)4 × 10^-5 1/M²∙s
D)1)3 × 10^-4 1/M²∙s

Question 40

The following set of data was obtained by the method of initial rates for the reaction:
BrO₃^-(aq)+ 5 Br^-(aq)+ 6 H⁺(aq)→ 3 Br₂(aq)+ 3 H₂O(l).
What is the rate law for the reaction?

A)Rate = k[BrO₃^-][Br^-][H⁺]⁴
B)Rate = k[BrO₃^-][Br^-][H⁺]^-4
C)Rate = k[BrO₃^-][Br^-][H⁺]^-2
D)Rate = k[BrO₃^-][Br^-][H⁺]²

Question 41

What is the decay constant for a radioactive isotope which decreases to 34% of its original value in 2.48 hours?

A)0)137 hr^-1
B)0)168 hr^-1
C)0)435 hr^-1
D)2)30 hr^-1

Question 42

An experiment with ⁵⁵Co takes 47.5 hours.At the end of the experiment,1.90 ng of ⁵⁵Co remains.If the half life is 18.0 hours,how many ng of ⁵⁵Co were originally present?

A)2)47 ng
B)3)05 ng
C)3)28 ng
D)11.8 ng

Question 43

Fluorine-18 is a radioisotope widely used in positron emission tomography to investigate brain activity.The half-life is 109.8 minutes.How long will it take for 2.75 μg of ¹⁸F to decay to 500 ng?

A)0)288 min
B)270 min
C)871 min
D)2)06 × 10³ min

Question 44

Iodine-123,used in thyroid therapy,has a half-life of 13.27 hours.How many half-lives are required for a 160 mg sample of iodine-123 to decay to 5.0 mg?

A)0)031
B)1)0
C)5)0
D)32

Question 45

The first-order reaction,SO₂Cl₂ → SO₂ + Cl₂,has a half-life of 8.75 hours at 593 K.How long will it take for the concentration of SO₂Cl₂ to fall to 12.5% of its initial value?

A)0)165 hr
B)3)22 hr
C)6)06 hr
D)26.2 hr

Question 46

The isomerization reaction,CH₃NC → CH₃CN,is first order and the rate constant is equal to
0)46 s^-1 at 600 K.What is the concentration of CH₃NC after 0.20 minutes if the initial concentration is 0.10 M?

A)4)0 x 10^-4 M
B)9)1 x 10^-4 M
C)4)0 x 10^-2 M
D)9)1 x 10^-2 M

Question 47

The half life of the reaction shown below is found not to depend on the concentration of H₂O₂(aq).
2 H₂O₂(aq)→ 2 H₂O(l)+ O₂(g)
What is the order of this reaction?

A)zeroth
B)first
C)second
D)third

Question 48

Acetaldehyde decomposes at 750 K: CH₃CHO → CO + CH₄.The reaction is first order in acetaldehyde and the half-life of the reaction is found to be 530 seconds.What is the rate constant for the reaction at this temperature?

A)2)7 x 10^-3 s^-1
B)1)3 x 10^-3 s^-1
C)2)7 x 10² s^-1
D)7)6 x 10² s^-1

Question 49

If a sample of ²³³Pa takes 62.7 days to decrease to 20.0% of its original mass,what is its half-life?

A)0)0370 days
B)27.0 days
C)157 days
D)195 days

Question 50

The decay constant,k,is given for each of the beta emitters below.Which one has the shortest half life?

A)(³⁶Cl,7.09 × 10^-24 s^-1)
B)(¹³¹I,9.94 × 10^-7 s^-1)
C)(⁴²K,1.55 × 10^-5 s^-1)
D)(⁶³Ni,2.39 × 10^-10 s^-1)

Question 51

The decomposition of cyclopropane,was observed at 500°C and its concentration was monitored as a function of time.The data set is given below.What is the order of the reaction with respect to cyclopropane?

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

Question 52

The first-order reaction,SO₂Cl₂ → SO₂ + Cl₂,has a rate constant equal to 2.20 × 10^-5 s^-1 at
593 K.What percentage of the initial amount of SO₂Cl₂ will remain after 2.00 hours?

A)1)00%
B)14.7%
C)17.1%
D)85.4%

Question 53

Fluorine-18 is an isotope used in Positron Emission Tomography (PET)to scan the brain.If a researcher has 1.50 μg of ¹⁸F,how long before it decays to 1.0 ng? The half-life of ¹⁸F is 109.8 minutes.

A)5)2 × 10^-2 hr
B)4)6 × 10^-2 hr
C)19 hr
D)51 hr

Question 54

What percentage of a radioactive substance remains after 6.00 half-lives have elapsed?

A)0)78%
B)1)56%
C)3)31%
D)6)25%

Question 55

The rate constant,k,for a first-order reaction is equal to 4.2 × 10^-4 s^-1.What is the half-life for the reaction?

A)2)9 × 10^-4 s
B)1)2 × 10³ s
C)1)7 × 10³ s
D)2)4 × 10³ s

Question 56

For the first-order reaction,2 N₂O(g)→ 2 N₂(g)+ O₂(g),what is the concentration of N₂O after 3 half-lives if 0.15 mol of N₂O is initially placed into in a 1.00-L reaction vessel?

A)9)4 × 10^-3 M
B)1)9 × 10^-2 M
C)3)8 × 10^-2 M
D)7)5 × 10^-2 M

Question 57

For a particular first-order reaction,it takes 48 minutes for the concentration of the reactant to decrease to 25% of its initial value.What is the value for rate constant (in s^-1)for the reaction?

A)1)0 × 10^-4 s^-1
B)4)8 × 10^-4 s^-1
C)6)0 × 10^-3 s^-1
D)2)9 × 10^-2 s^-1

Question 58

Neptunium-239 has a half-life of 2.35 days.How many days must elapse for a sample of ²³⁹Np to decay to 1.00% of its original quantity?

A)0)0640 days
B)0)736 days
C)1)36 days
D)15.6 days

Question 59

The following reaction is first order: C₂H₆ → 2 CH₃.If the rate constant is equal to 5.5 × 10^-4 s^-1 at 1000 K,how long will it take for 0.35 mol of C₂H₆ in a 1.00 L container to decrease to 0.10 mol in the same container?

A)7)6 min
B)38 min
C)106 min
D)131 min

Question 60

The first-order reaction,2 N₂O(g)→ 2 N₂(g)+ O₂(g),has a rate constant equal to 0.76 s^-1 at
1000 K.How long will it take for the concentration of N₂O to decrease to 42% of its initial concentration?

A)0)88 s
B)1)1 s
C)1)8 s
D)2)4 s

Question 61

For the hypothetical second order reaction: A → products,the general rate law is: rate = k[A]².How long is the third half-life of the reaction if [A]₀ is 0.080 M and the first half-life is 22 minutes?

A)0)57 min
B)1)7 min
C)7)3 min
D)88 min

Question 62

Nitrogen dioxide decomposes at 300°C via a second-order process to produce nitrogen monoxide and oxygen according to the following chemical equation.
2 NO₂(g)→ 2 NO(g)+ O₂(g).
A sample of NO₂(g)is initially placed in a 2.50-L reaction vessel at 300°C.If the half-life and the rate constant at 300°C are 11 seconds and 0.54 M^-1 s^-1,respectively,how many moles of NO₂ were in the original sample?

A)0)17 mol
B)0)42 mol
C)5)9 mol
D)15 mol

Question 63

In aqueous solution,hypobromite ion,BrO^-,reacts to produce bromate ion,BrO₃^-,and bromide ion,Br^-,according to the following chemical equation.
3 BrO^-(aq)→ BrO₃^-(aq)+ 2 Br^-(aq)
A plot of 1/[BrO^-] vs.time is linear and the slope is equal to 0.056 M^-1s^-1.If the initial concentration of BrO^- is 0.80 M,how long will it take one-half of the BrO^- ion to react?

A)4)5 × 10^-2 s
B)7)1 s
C)12 s
D)22 s

Question 64

The second-order reaction,2 Mn(CO)₅ → Mn₂(CO)₁₀ has a rate constant equal to 3.0 × 10⁹ M^-1s^-1 at 25°C.If the initial concentration of Mn(CO)₅ is 1.0 × 10^-5 M,how long will it take for 90.% of the reactant to disappear?

A)3)3 × 10^-16 s
B)3)7 × 10^-15 s
C)3)0 × 10^-4 s
D)3)0 × 10³ s

Question 65

If the units for rate are M s^-1,what are the units for the rate constant,k,for a zeroth-order reaction?

A)s^-1
B)M^-1
C)M s^-1
D)M^-1 s^-1

Question 66

A mechanism for a naturally occurring reaction that destroys ozone is:
Step 1: O₃(g)+ HO(g)→ HO₂(g)+ O₂(g)
Step 2: HO₂(g)+ O(g)→ HO(g)+ O₂(g)
What is the molecularity of the overall reaction?

A)unimolecular
B)bimolecular
C)none of these because molecularity is the difference of the exponents in the rate law
D)none of these because molecularity only refers to elementary steps

Question 67

A researcher needs 5.00 mg of ¹²⁸Ba for an experiment.If the half-life of ¹²⁸Ba is 2.43 days,how many milligrams of ¹²⁸BaCl₂ must she order from the manufacturer if it takes 4.50 days to ship the material from the manufacturer to the university? (Assume the molar mass of ¹²⁸Ba is 128 g/mol. )

A)11.6 mg
B)18.0 mg
C)21.5 mg
D)44.9 mg

Question 68

The reaction: 2 HI → H₂ + I₂,is second order and the rate constant at 800 K is 9.70 × 10^-2 M^-1 s^-1.How long will it take for 8.00 × 10^-2 mol/L of HI to decrease to one-fourth of its initial concentration?

A)0)619 s
B)124 s
C)387 s
D)429 s

Question 69

Hydrogen iodide decomposes at 800 K via a second-order process to produce hydrogen and iodine according to the following chemical equation.
2 HI(g)→ H₂(g)+ I₂(g)
At 800 K it takes 142 seconds for the initial concentration of HI to decrease from 6.75 × 10^-2 M to 3.50 × 10^-2 M.What is the rate constant for the reaction at this temperature?

A)5)12 × 10^-4 M^-1s^-1
B)9)69 × 10^-2 M^-1s^-1
C)10.3 M^-1s^-1
D)1)95 × 10³ M^-1s^-1

Question 70

A plot of 1/[BrO^-] vs time is linear for the reaction:
3 BrO^-(aq)→ BrO₃^-(aq)+ 2 Br^-(aq)
What is the order of the reaction with respect to the hypobromite ion,BrO^-?

A)0
B)1
C)2
D)3

Question 71

The elementary reaction representing the formation of ozone:
Is an example of a ________ reaction.

A)unimolecular
B)bimolecular
C)termolecular
D)tetramolecular

Question 72

For the zeroth-order reaction: A → products,what will happen to the rate of reaction if the concentration of A is doubled?

A)The rate will be halved.
B)The rate will be doubled.
C)The rate will be quadrupled.
D)The rate will remain the same.

Question 73

A mechanism for a naturally occurring reaction that destroys ozone is:
Step 1: O₃(g)+ HO(g)→ HO₂(g)+ O₂(g)
Step 2: HO₂(g)+ O(g)→ HO(g)+ O₂(g)
Which species is an intermediate?

A)HO
B)HO₂
C)O
D)O₃

Question 74

For the zeroth-order reaction: C → products,-Δ[C]/Δt = k,which of the following graphs would be expected to give a straight line?

A)[C] vs.t
B)ln[C] vs.t
C)1/[C] vs.t
D)[C]² vs.t

Question 75

Which statement below regarding the half-life of a second-order reaction is true?

A)Each half-life is half as long as the preceding one.
B)Each half-life is twice as long as the preceding one.
C)Each half-life is four times as long as the preceding one.
D)The length of the half-life remains unchanged throughout the course of the reaction.

Question 76

The slowest step in a reaction mechanism is called the ________ step.

A)activation
B)elementary
C)rate law
D)rate-determining

Question 77

The elementary reaction: 2 HI → H₂ + I₂,is an example of a ________ reaction.

A)unimolecular
B)bimolecular
C)termolecular
D)tetramolecular

Question 78

A three-step mechanism has been suggested for the formation of carbonyl chloride:
Step 1: Cl₂ → 2 Cl
Step 2: Cl + CO → COCl
Step 3: COCl + Cl₂ → COCl₂ + Cl
Which species is an intermediate in the mechanism?

A)Cl
B)CO
C)COCl
D)COCl₂

Question 79

Which statement below regarding the half-life of a zeroth-order reaction is true?

A)Each half-life is half as long as the preceding half-life.
B)Each half-life is twice as long as the preceding half-life.
C)Each half-life is four times as long as the preceding half-life.
D)The half-life remains unchanged throughout the course of the reaction.

Question 80

The decomposition of ozone in the stratosphere can occur by the following two-step mechanism:
Step 1: Br + O₃ → BrO + O₂
Step 2: BrO + O → Br + O₂
Which species is an intermediate in this mechanism?

A)Br
B)BrO
C)O
D)O₃