Question 1

The reaction below is first order in H2 and one-half order in Br2.The rate law for this reaction is ________.
H2(g)+ Br2(g)→ 2 HBr(g)

Accepted Answer

Question 2

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?

Accepted Answer

A) 5)00 × 10-4 M 
B) 5)25 × 10-4 M 
C) 5)50 × 10-4 M 
D) 6)00 × 10-4 M 
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 3

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)

Accepted Answer

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- 
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-

Question 4

Consider the first-order reaction A → B in which A molecules (shaded spheres)are converted to B molecules (unshaded spheres).  
-Which drawing (a)-(d)represents the reaction mixture at t = 3 minutes?

Accepted Answer

A) drawing (a) 
B) drawing (b) 
C) drawing (c) 
D) drawing (d) 
A) drawing (a) 
B) drawing (b) 
C) drawing (c) 
D) drawing (d)

Question 5

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?  
= ?

Accepted Answer

A)    
B)    
C)    
D) none of these 
A)    
B)    
C)    
D) none of these

Question 6

A reaction has the rate law Rate = k[NO]2[H2].If the concentration of NO is reduced by half and the concentration of H2 is quadrupled,the rate of reaction will ________ (increase,decrease,not change).

Accepted Answer

Question 7

For the first-order reaction,2 N2O(g)→ 2 N2(g)+ O2(g),what is the concentration of N2O after 3 half-lives if 0.25 mol of N2O is initially placed into a 1.00-L reaction vessel?

Accepted Answer

A) 1)6 × 10- 2 M 
B) 3)1 × 10- 2 M 
C) 6)2 × 10- 2 M 
D) 1)2 × 10- 1 M 
A) 1)6 × 10- 2 M 
B) 3)1 × 10- 2 M 
C) 6)2 × 10- 2 M 
D) 1)2 × 10- 1 M

Question 8

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?

Accepted Answer

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 
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 9

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

Accepted Answer

A) Br 
B) BrO 
C) O 
D) O3 
A) Br 
B) BrO 
C) O 
D) O3

Question 10

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?

Accepted Answer

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

Question 11

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

Accepted Answer

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. 
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 12

A gaseous reaction occurs by a two-step mechanism,shown below.
Step 1: AX +Y2 ⇌ AXY2 fast
Step 2: AXY2 + AX → 2 AXY slow
Including concentration of only reactants and products,what is the rate law for this reaction?

Accepted Answer

A) Rate = k[AX][Y2] 
B) Rate = k[AXY2]/[AX][Y2] 
C) Rate = k[AX]2[Y2] 
D) Rate = k[AXY]2/[AXY2][AX] 
A) Rate = k[AX][Y2] 
B) Rate = k[AXY2]/[AX][Y2] 
C) Rate = k[AX]2[Y2] 
D) Rate = k[AXY]2/[AXY2][AX]

Question 13

The reaction for the decomposition of dinitrogen monoxide gas to form oxygen radicals is:
N2O(g) $\rarr$ N2(g)+ O(g).If the rate constant is 3.04 × 10-2 s-1 and the frequency factor is
8)00 × 1011 s-1,what is the activation energy for the first-order reaction at 700°C?

Accepted Answer

A) 0)262 kJ/mol 
B) 38.2 kJ/mol 
C) 180 kJ/mol 
D) 250 kJ/mol 
A) 0)262 kJ/mol 
B) 38.2 kJ/mol 
C) 180 kJ/mol 
D) 250 kJ/mol

Question 14

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?

Accepted Answer

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 
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 15

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?

Accepted Answer

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 
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 16

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

Accepted Answer

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

Question 17

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-?

Accepted Answer

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

Question 18

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?

Accepted Answer

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 
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 19

-What is the activation energy for the formation of ozone?

Accepted Answer

A) 14 kJ 
B) 392 kJ 
C) 406 kJ 
D) none of these 
A) 14 kJ 
B) 392 kJ 
C) 406 kJ 
D) none of these

Question 20

The first-order isomerization reaction: cyclopropane → propene,has a rate constant of
1)10 × 10-4s-1 at 470°C and an activation energy of 264 kJ/mol.What is the temperature of the reaction when the rate constant is equal to 4.36 × 10-3s-1?

Accepted Answer

A) 126°C 
B) 411°C 
C) 510°C 
D) 540°C 
A) 126°C 
B) 411°C 
C) 510°C 
D) 540°C

Exam 12: Chemical Kinetics

The reaction below is first order in H2 and one-half order in Br2.The rate law for this reaction is ________. H2(g)+ Br2(g)→ 2 HBr(g)

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?

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)

Consider the first-order reaction A → B in which A molecules (shaded spheres)are converted to B molecules (unshaded spheres). -Which drawing (a)-(d)represents the reaction mixture at t = 3 minutes?

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 reaction has the rate law Rate = k[NO]2[H2].If the concentration of NO is reduced by half and the concentration of H2 is quadrupled,the rate of reaction will ________ (increase,decrease,not change).

For the first-order reaction,2 N2O(g)→ 2 N2(g)+ O2(g),what is the concentration of N2O after 3 half-lives if 0.25 mol of N2O is initially placed into a 1.00-L reaction vessel?

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?

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

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?

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

A gaseous reaction occurs by a two-step mechanism,shown below. Step 1: AX +Y2 ⇌ AXY2 fast Step 2: AXY2 + AX → 2 AXY slow Including concentration of only reactants and products,what is the rate law for this reaction?

The reaction for the decomposition of dinitrogen monoxide gas to form oxygen radicals is: N2O(g) →\rarr→ N2(g)+ O(g).If the rate constant is 3.04 × 10-2 s-1 and the frequency factor is 8)00 × 1011 s-1,what is the activation energy for the first-order reaction at 700°C?

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?

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 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-?

-What is the activation energy for the formation of ozone?

The first-order isomerization reaction: cyclopropane → propene,has a rate constant of 1)10 × 10-4s-1 at 470°C and an activation energy of 264 kJ/mol.What is the temperature of the reaction when the rate constant is equal to 4.36 × 10-3s-1?

Chemistry: Matter and Measurement

Atoms, molecules, and Ions

Formulas, equations, and Moles

Reactions in Aqueous Solutions

Periodicity and the Atomic Structure of Atoms

Ionic Bonds and Some Main-Group Chemistry

Covalent Bonds and Molecular Structure

Thermochemistry: Chemical Energy

Gases: Their Properties and Behavior

Liquids,solids,and Phase Changes

Solutions and Their Properties

Chemical Equilibrium

Aqueous Equilibria: Acids and Bases

Applications of Aqueous Equilibria

Thermodynamics: Entropy, free Energy, and Equilibrium

Electrochemistry

Hydrogen, oxygen, and Water

The Main-Group Elements

Transition Elements and Coordination Chemistry

Metals and Solid-State Materials

Nuclear Chemistry

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Filters

The reaction below is first order in H₂ and one-half order in Br₂.The rate law for this reaction is ________. H₂(g)+ Br₂(g)→ 2 HBr(g)

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?

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)

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 reaction has the rate law Rate = k[NO]²[H₂].If the concentration of NO is reduced by half and the concentration of H₂ is quadrupled,the rate of reaction will ________ (increase,decrease,not change).

For the first-order reaction,2 N₂O(g)→ 2 N₂(g)+ O₂(g),what is the concentration of N₂O after 3 half-lives if 0.25 mol of N₂O is initially placed into a 1.00-L reaction vessel?

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?

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

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 gaseous reaction occurs by a two-step mechanism,shown below. Step 1: AX +Y₂ ⇌ AXY_{2 fast} Step 2: AXY₂ + AX → 2 AXY slow Including concentration of only reactants and products,what is the rate law for this reaction?

The reaction for the decomposition of dinitrogen monoxide gas to form oxygen radicals is: N₂O(g) $\rarr$ N₂(g)+ O(g).If the rate constant is 3.04 × 10^-2 s^-1 and the frequency factor is 8)00 × 10¹¹ s^-1,what is the activation energy for the first-order reaction at 700°C?

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 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^-?

The first-order isomerization reaction: cyclopropane → propene,has a rate constant of 1)10 × 10^-4s^-1 at 470°C and an activation energy of 264 kJ/mol.What is the temperature of the reaction when the rate constant is equal to 4.36 × 10^-³s^-1?