Question 1

2NOBr(g)  → 2NO(g)  + Br2(g)  [NOBr](mol L-1)  Rate (molL-1s-1) 
0) 0450 1.62 × 10-3
0) 0310 7.69 × 10-4
0) 0095 7.22 × 10-5
Based on the initial rate data above, what is the value of the rate constant?

Accepted Answer

A)   0.0360 L mol-1s-1
B)   0.800 L mol-1s-1
C)   1.25 L mol-1s-1
D)   27.8 L mol-1s-1
E)   0.0360 s-1F) A) and E)
G) None of the above

Question 2

What is the molecularity of the following elementary reaction? NH2Cl(aq)  + OH- (aq)  → NHCl- (aq)  + H2O(l)

Accepted Answer

A)   Unimolecular
B)   Bimolecular
C)   Termolecular
D)   Tetramolecular
E)   Need to know the reaction order before molecularity can be determined.F) All of the above
G) D) and E)

Question 3

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°rxn = + 55 kJ/mol. What is the activation energy for the reverse reaction?

Accepted Answer

A)   27 kJ/mol
B)   47 kJ/mol
C)   55 kJ/mol
D)   102 kJ/mol
E)   More information is needed, since this is a Hess's law calculation.F) None of the above
G) A) and B) B

Question 4

Consider the reaction 2A + 2B + C → 2D + E
If the rate law for this reaction is Rate = k[A][B]2, what will be the effect on the rate if the concentrations of A, B and C are all doubled at the same time?

Accepted Answer

A)   The rate will increase by a factor of 2.
B)   The rate will increase by a factor of 4.
C)   The rate will increase by a factor of 6.
D)   The rate will increase by a factor of 8.
E)   More information is needed before this question can be answered.F) C) and D)
G) B) and D) D

Question 5

When the reaction A → B + C is studied, a plot of ln[A]t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Accepted Answer

A)   Zero
B)   First
C)   Second
D)   Third
E)   More information is needed to determine the order.F) A) and E)
G) A) and D)

Question 6

Ammonium cyanate (NH4CNO)  reacts to form urea (NH2CONH2) . At 65°C the rate constant, k, is 3.60 L mol-1s-1.What is the rate law for this reaction?

Accepted Answer

A)   Rate = 3.60 L mol-1s-1[NH4CNO]
B)   Rate = 3.60 L mol-1s-1 [NH4CNO]2
C)   Rate = 0.28 mol L-1s-1 [NH4CNO]
D)   Rate = 0.28 mol L-1s-1[NH4CNO]2
E)   Rate = 3.60 L mol-1s-1 [NH2CONH2]-1F) A) and E)
G) A) and D)

Question 7

For the reaction A(g)  + 2B(g)  → 2C(g)  + 2D(g) 
The following data were collected at constant temperature. Determine the correct rate law for this reaction.
Trial Initial [A] Initial [B] Initial Rate
(mol/L)  (mol/L)  (mol/(L·min) ) 
1 0) 125 0.200 7.25
2 0) 375 0.200 21.75
3 0) 250 0.400 14.50
4 0) 375 0.400 21.75

Accepted Answer

A)   Rate = k[A] [B]
B)   Rate = k[A]2 [B]
C)   Rate = k[A] [B]2
D)   Rate = k[A]
E)   Rate = k[A]3F) None of the above
G) A) and B)

Question 8

A reaction has the following rate law: Rate = k[A][B]2
In experiment 1, the concentrations of A and B are both 0.10 mol L-1; in experiment 2, the concentrations are both 0.30 mol L-1. If the temperature stays constant, what is the value of the ratio, Rate(2) /Rate(1) ?

Accepted Answer

A)   3.0
B)   6.0
C)   9.0
D)   18
E)   27F) C) and E)
G) A) and B)

Question 9

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 + + H2O2   H2O+-OH (rapid equilibrium)  H2O+-OH + Br- → HOBr + H2O (slow)  HOBr + H+ + Br- → Br2 + H2O (fast)  Which of the following rate laws is consistent with the mechanism? A)  Rate = k[H2O2][H+]2[Br-] B)  Rate = k[H2O+-OH][Br-] C)  Rate = k[H2O2][H+][Br-] D)  Rate = k[HOBr][H+][Br-][H2O2] E)  Rate = k[Br-]" class="answers-bank-image d-inline" rel="preload" > H2O+-OH (rapid equilibrium) 
H2O+-OH + Br- → HOBr + H2O (slow) 
HOBr + H+ + Br- → Br2 + H2O (fast) 
Which of the following rate laws is consistent with the mechanism?

Accepted Answer

A)   Rate = k[H2O2][H+]2[Br-]
B)   Rate = k[H2O+-OH][Br-]
C)   Rate = k[H2O2][H+][Br-]
D)   Rate = k[HOBr][H+][Br-][H2O2]
E)   Rate = k[Br-]F) A) and D)
G) A) and E)

Question 10

A catalyst lowers the activation energy but does not affect the mechanism of a reaction.

Accepted Answer

A) True 
 B)False

Question 11

Butadiene, C4H6 (used to make synthetic rubber and latex paints)  reacts to C8H12 with a rate law of rate = 0.014 L/(mol·s)  [C4H6]2. What will be the concentration of C4H6 after 3.0 hours if the initial concentration is 0.025 M?

Accepted Answer

A)   0.0052 M
B)   0.024 M
C)   43 M
D)   190 M
E)   0.0000 MF) C) and D)
G) A) and E)

Question 12

Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of -0.208 hr-1 results. What is the rate law for the reaction?

Accepted Answer

A)   Rate = 0.208 hr-1 [sucrose]2
B)   Rate = 0.208 hr-1 [sucrose]
C)   Rate = 0.0433 hr [sucrose]2
D)   Rate = 0.0433 hr [sucrose]
E)   Rate = 0.208 mol L-1hr-1 [sucrose]0F) C) and D)
G) D) and E)

Question 13

A reaction has an activation energy of 195.0 kJ/mol. When the temperature is increased from 200°C to 220°C, the rate constant will increase by a factor of

Accepted Answer

A)   1.1.
B)   4.3 × 104.
C)   3.2.
D)   7.5.
E)   None of these choices are correct.F) C) and D)
G) A) and E)

Question 14

Consider the general reaction 5Br-(aq)  + BrO3-(aq)  + 6H+(aq)  → 3Br2(aq)  + 3H2O(aq) 
For this reaction, the rate when expressed as Δ[Br2]/Δt is the same as

Accepted Answer

A)   -Δ[H2O]/Δt
B)   3Δ[BrO3-]/Δt
C)   -5Δ[Br-]/Δt
D)   -0.6Δ[Br-]/Δt
E)   None of these choices are correct.F) A) and B)
G) A) and E) D

Question 15

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Accepted Answer

A)   0.94
B)   0.87
C)   0.75
D)   0.13
E)   0.063F) A) and B)
G) All of the above

Question 16

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Accepted Answer

A) True 
 B)False

Question 17

The rate law cannot be predicted from the stoichiometry of a reaction.

Accepted Answer

A) True 
 B)False

Question 18

Sulfur trioxide can undergo decomposition according to the equation 2SO3 → 2SO2 + O2
For this reaction, rate = -0.5Δ[SO3 ]/Δt = k[SO3]2. If the reaction rate is 1.75 × 10-7 mol L-1 min-1 when the concentration of sulfur trioxide is 5.4 × 10-3 mol L-1, what is the value of the rate constant k?

Accepted Answer

A)   3.2 × 10-5 L mol-1 min-1
B)   1.6 × 10-5 L mol-1 min-1
C)   6.0 × 10-3 L mol-1 min-1
D)   3.0 × 10-3 L mol-1 min-1
E)   1.6 × 10-2 L mol-1 min-1F) C) and E)
G) A) and D)

Question 19

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 + + H2O2   H2O+-OH (rapid equilibrium)  H2O+-OH + Br- → HOBr + H2O (slow)  HOBr + H+ + Br- → Br2 + H2O (fast)  What is the overall reaction equation for this process? A)  2H2O+-OH + 2Br- → H2O2 + Br2 + 2H2O B)  2H+ + 2Br- + H2O2 → Br2 + 2H2O C)  2H+ + H2O2 + Br- + HOBr → H2O+-OH + Br2 + H2O D)  H2O+-OH + Br- + H+ → Br2 + H2O E)  None of these choices are correct." class="answers-bank-image d-inline" rel="preload" > H2O+-OH (rapid equilibrium) 
H2O+-OH + Br- → HOBr + H2O (slow) 
HOBr + H+ + Br- → Br2 + H2O (fast) 
What is the overall reaction equation for this process?

Accepted Answer

A)   2H2O+-OH + 2Br- → H2O2 + Br2 + 2H2O
B)   2H+ + 2Br- + H2O2 → Br2 + 2H2O
C)   2H+ + H2O2 + Br- + HOBr → H2O+-OH + Br2 + H2O
D)   H2O+-OH + Br- + H+ → Br2 + H2O
E)   None of these choices are correct.F) A) and E)
G) C) and D)

Question 20

The units of the rate of reaction depend on the order of the reaction.

Accepted Answer

A) True 
 B)False

Exam 16: Kinetics Rates and Mechanisms of Chemical Reactions

2NOBr(g) → 2NO(g) + Br₂(g) [NOBr](mol L^-1) Rate (molL^-1s^-1) 0) 0450 1.62 × 10^-3 0) 0310 7.69 × 10^-4 0) 0095 7.22 × 10^-5 Based on the initial rate data above, what is the value of the rate constant?

Correct Answer
verified

What is the molecularity of the following elementary reaction? NH₂Cl(aq) + OH_- (aq) → NHCl_- (aq) + H₂O(l)

Correct Answer
verified

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°_rxn = + 55 kJ/mol. What is the activation energy for the reverse reaction?

Correct Answer
verified
B

Consider the reaction 2A + 2B + C → 2D + E If the rate law for this reaction is Rate = k[A][B]², what will be the effect on the rate if the concentrations of A, B and C are all doubled at the same time?

Correct Answer
verified
D

When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Correct Answer
verified

Ammonium cyanate (NH₄CNO) reacts to form urea (NH₂CONH₂) . At 65°C the rate constant, k, is 3.60 L mol^-1s^-1.What is the rate law for this reaction?

Correct Answer
verified

Correct Answer
verified

A reaction has the following rate law: Rate = k[A][B]₂ In experiment 1, the concentrations of A and B are both 0.10 mol L^-1; in experiment 2, the concentrations are both 0.30 mol L^-1. If the temperature stays constant, what is the value of the ratio, Rate(2) /Rate(1) ?

Correct Answer
verified

Correct Answer
verified

A catalyst lowers the activation energy but does not affect the mechanism of a reaction.

Correct Answer
verified

Butadiene, C₄H₆ (used to make synthetic rubber and latex paints) reacts to C₈H₁₂ with a rate law of rate = 0.014 L/(mol·s) [C₄H₆]². What will be the concentration of C₄H₆ after 3.0 hours if the initial concentration is 0.025 M?

Correct Answer
verified

Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of -0.208 hr^-1 results. What is the rate law for the reaction?

Correct Answer
verified

A reaction has an activation energy of 195.0 kJ/mol. When the temperature is increased from 200°C to 220°C, the rate constant will increase by a factor of

Correct Answer
verified

Consider the general reaction 5Br^-(aq) + BrO₃^-(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(aq) For this reaction, the rate when expressed as Δ[Br₂]/Δt is the same as

Correct Answer
verified
D

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Correct Answer
verified

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Correct Answer
verified

The rate law cannot be predicted from the stoichiometry of a reaction.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The units of the rate of reaction depend on the order of the reaction.

Correct Answer
verified

Exam 16: Kinetics Rates and Mechanisms of Chemical Reactions

2NOBr(g) → 2NO(g) + Br2(g) [NOBr](mol L-1) Rate (molL-1s-1) 0) 0450 1.62 × 10-3 0) 0310 7.69 × 10-4 0) 0095 7.22 × 10-5 Based on the initial rate data above, what is the value of the rate constant?

Correct AnswerverifiedShow Answer

What is the molecularity of the following elementary reaction? NH2Cl(aq) + OH- (aq) → NHCl- (aq) + H2O(l)

Correct AnswerverifiedShow Answer

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°rxn = + 55 kJ/mol. What is the activation energy for the reverse reaction?

Correct AnswerverifiedB

Consider the reaction 2A + 2B + C → 2D + E If the rate law for this reaction is Rate = k[A][B]2, what will be the effect on the rate if the concentrations of A, B and C are all doubled at the same time?

Correct AnswerverifiedD

When the reaction A → B + C is studied, a plot of ln[A]t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Correct AnswerverifiedShow Answer

Ammonium cyanate (NH4CNO) reacts to form urea (NH2CONH2) . At 65°C the rate constant, k, is 3.60 L mol-1s-1.What is the rate law for this reaction?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A reaction has the following rate law: Rate = k[A][B]2 In experiment 1, the concentrations of A and B are both 0.10 mol L-1; in experiment 2, the concentrations are both 0.30 mol L-1. If the temperature stays constant, what is the value of the ratio, Rate(2) /Rate(1) ?

Correct AnswerverifiedShow Answer

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 H2O+-OH (rapid equilibrium) H2O+-OH + Br- → HOBr + H2O (slow) HOBr + H+ + Br- → Br2 + H2O (fast) Which of the following rate laws is consistent with the mechanism?

Correct AnswerverifiedShow Answer

A catalyst lowers the activation energy but does not affect the mechanism of a reaction.

Correct AnswerverifiedShow Answer

Butadiene, C4H6 (used to make synthetic rubber and latex paints) reacts to C8H12 with a rate law of rate = 0.014 L/(mol·s) [C4H6]2. What will be the concentration of C4H6 after 3.0 hours if the initial concentration is 0.025 M?

Correct AnswerverifiedShow Answer

Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of -0.208 hr-1 results. What is the rate law for the reaction?

Correct AnswerverifiedShow Answer

A reaction has an activation energy of 195.0 kJ/mol. When the temperature is increased from 200°C to 220°C, the rate constant will increase by a factor of

Correct AnswerverifiedShow Answer

Consider the general reaction 5Br-(aq) + BrO3-(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(aq) For this reaction, the rate when expressed as Δ[Br2]/Δt is the same as

Correct AnswerverifiedD

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Correct AnswerverifiedShow Answer

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Correct AnswerverifiedShow Answer

The rate law cannot be predicted from the stoichiometry of a reaction.

Correct AnswerverifiedShow Answer

Sulfur trioxide can undergo decomposition according to the equation 2SO3 → 2SO2 + O2 For this reaction, rate = -0.5Δ[SO3 ]/Δt = k[SO3]2. If the reaction rate is 1.75 × 10-7 mol L-1 min-1 when the concentration of sulfur trioxide is 5.4 × 10-3 mol L-1, what is the value of the rate constant k?

Correct AnswerverifiedShow Answer

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 H2O+-OH (rapid equilibrium) H2O+-OH + Br- → HOBr + H2O (slow) HOBr + H+ + Br- → Br2 + H2O (fast) What is the overall reaction equation for this process?

Correct AnswerverifiedShow Answer

The units of the rate of reaction depend on the order of the reaction.

Correct AnswerverifiedShow Answer

2NOBr(g) → 2NO(g) + Br₂(g) [NOBr](mol L^-1) Rate (molL^-1s^-1) 0) 0450 1.62 × 10^-3 0) 0310 7.69 × 10^-4 0) 0095 7.22 × 10^-5 Based on the initial rate data above, what is the value of the rate constant?

Correct Answer
verified

What is the molecularity of the following elementary reaction? NH₂Cl(aq) + OH_- (aq) → NHCl_- (aq) + H₂O(l)

Correct Answer
verified

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and ΔH°_rxn = + 55 kJ/mol. What is the activation energy for the reverse reaction?

Correct Answer
verified
B

Consider the reaction 2A + 2B + C → 2D + E If the rate law for this reaction is Rate = k[A][B]², what will be the effect on the rate if the concentrations of A, B and C are all doubled at the same time?

Correct Answer
verified
D

When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Correct Answer
verified

Ammonium cyanate (NH₄CNO) reacts to form urea (NH₂CONH₂) . At 65°C the rate constant, k, is 3.60 L mol^-1s^-1.What is the rate law for this reaction?

Correct Answer
verified

Correct Answer
verified

A reaction has the following rate law: Rate = k[A][B]₂ In experiment 1, the concentrations of A and B are both 0.10 mol L^-1; in experiment 2, the concentrations are both 0.30 mol L^-1. If the temperature stays constant, what is the value of the ratio, Rate(2) /Rate(1) ?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Butadiene, C₄H₆ (used to make synthetic rubber and latex paints) reacts to C₈H₁₂ with a rate law of rate = 0.014 L/(mol·s) [C₄H₆]². What will be the concentration of C₄H₆ after 3.0 hours if the initial concentration is 0.025 M?

Correct Answer
verified

Sucrose decomposes to fructose and glucose in acid solution. When ln [sucrose] is plotted vs. time, a straight line with slope of -0.208 hr^-1 results. What is the rate law for the reaction?

Correct Answer
verified

Correct Answer
verified

Consider the general reaction 5Br^-(aq) + BrO₃^-(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(aq) For this reaction, the rate when expressed as Δ[Br₂]/Δt is the same as

Correct Answer
verified
D

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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