Question 1

In going from room temperature (25.0 °C)  to 10 °C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

Accepted Answer

A)   157.2 kJ/mol
B)   103.8 kJ/mol
C)   52.9 kJ/mol
D)   6.4 kJ/mol
E)   <1 kJ/molF) A) and B)
G) C) and E)

Question 2

For the reaction 2A + B + 2C  D + E
The following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.  D + E The following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.   A)  Rate = k[A][B][C] B)  Rate = k [A]2[B][C] C)  Rate = k [A]2[B][C]-1 D)  Rate = k [A][B]2[C] -1 E)  none of the above" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   Rate = k[A][B][C]
B)   Rate = k [A]2[B][C]
C)   Rate = k [A]2[B][C]-1
D)   Rate = k [A][B]2[C] -1
E)   none of the aboveF) B) and D)
G) C) and D)

Question 3

The compound RX3 decomposes according to the equation 3RX3  R + R2X3 + 3X2
In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of reaction over the entire experiment? 3 decomposes according to the equation 3RX3  R + R2X3 + 3X2 In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of reaction over the entire experiment?   A)  0.011 mol L-1s-1 B)  0.019 mol L-1s-1 C)  0.044 mol L-1s-1 D)  0.049 mol L-1s-1 E)  0.069 mol L-1s-1" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   0.011 mol L-1s-1
B)   0.019 mol L-1s-1
C)   0.044 mol L-1s-1
D)   0.049 mol L-1s-1
E)   0.069 mol L-1s-1F) A) and B)
G) A) and C)

Question 4

The rate law for the reaction 3A  C is Rate = 4.36 × 10-2 L mol-1 hr-1[A]2
What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Accepted Answer

A)   0.0109 hr
B)   0.0629 hr
C)   15.9 hr
D)   23.9 hr
E)   91.7 hrF) A) and E)
G) C) and E)

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

A transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram.

Accepted Answer

A) True 
 B)False

Question 7

A catalyst accelerates a reaction because

Accepted Answer

A)   it increases the number of molecules with energy equal to or greater than the activation energy.
B)   it lowers the activation energy for the reaction.
C)   it increases the number of collisions between molecules.
D)   it increases the temperature of the molecules in the reaction.
E)   it supplies energy to reactant molecules.F) A) and D)
G) B) and C)

Question 8

Briefly outline the key arguments in the collision theory of reaction rates for the elementary reaction
C + D F1F1F1S1F1F1F10 products
Show that this theory predicts a second-order rate law, and how it predicts the form of the rate constant k.

Accepted Answer

For reaction to occur, the molecules mus...

Question 9

Briefly list the features/properties common to all catalysts and how they work. Draw a labeled reaction energy diagram as part of your answer.

Accepted Answer

Catalysts speed up a reaction ...

Question 10

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

Accepted Answer

A) True 
 B)False

Question 11

The decomposition of dinitrogen pentaoxide has an activation energy of 102 kJ/mol and H°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) A) and C)
G) A) and B)

Question 12

The rate constant for a reaction is 4.65 L mol-1s-1. What is the overall order of the reaction?

Accepted Answer

A)   zero
B)   first
C)   second
D)   third
E)   More information is needed to determine the overall order.F) C) and E)
G) B) and D)

Question 13

Cyclobutane decomposes to ethene in a first-order reaction. From measurements of the rate constant (k) at various absolute temperatures (T), the accompanying Arrhenius plot was obtained (ln k versus 1/T).  a. Calculate the energy of activation, Ea.
b. Determine the value of the rate constant at 740. K. (In the plot, the units of k are s-1.)

Accepted Answer

a. 260 ± 2...

Question 14

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

Question 15

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) B) and E)

Question 16

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year-1. What fraction of the tritium initially in a sample is still present 30 years later?

Accepted Answer

A)   0.19
B)   0.60
C)   0.15
D)   2.8 × 10-38
E)   none of the aboveF) All of the above
G) B) and E)

Question 17

In the collision theory of reaction rates, the rate constant for a bimolecular reaction can be written as
k = zF1F1F1S1F1F1F10pF1F1F1S1F1F1F10exp(-Ea/RT)
In one sentence each, clearly explain the physical meaning (interpretation) of the following three factors which appear in the above expression:
a. z
b. p
c. exp(-Ea/RT)

Accepted Answer

a. z is a collision rate constant, such ...

Question 18

The reaction CH3NC(g)   CH3CN(g)  is first-order with respect to methyl isocyanide, CH3NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min-1?

Accepted Answer

A)   -0.135 min-1
B)   0.0279 min-1
C)   0.089 min-1
D)   0.135 min-1
E)   35.8 min-1F) B) and C)
G) B) and D)

Question 19

For the reaction 3A(g)  + 2B(g)   2C(g)  + 2D(g) 
The following data were collected at constant temperature. Determine the correct rate law for this reaction.  2C(g)  + 2D(g)  The following data were collected at constant temperature. Determine the correct rate law for this reaction.   A)  Rate = k[A][B] B)  Rate = k[A][B]2 C)  Rate = k[A]3[B]2 D)  Rate = k[A]1.5[B] E)  Rate = k[A]2[B]" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   Rate = k[A][B]
B)   Rate = k[A][B]2
C)   Rate = k[A]3[B]2
D)   Rate = k[A]1.5[B]
E)   Rate = k[A]2[B]F) B) and D)
G) A) and E)

Question 20

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10-4 mol L-1 and the rate constant k = 1.08 × 10-6 s-1, what concentration of R remains after 25 days?

Accepted Answer

A)   1.0 × 10-3 mol L-1
B)   1.0 × 10-4 mol L-1
C)   9.6 × 10-5 mol L-1
D)   4.3 × 10-5 mol L-1
E)   9.7 × 10-6 mol L-1F) A) and B)
G) A) and C)

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

For the reaction 3A(g) + 2B(g)  2C(g) + 2D(g) The following data were collected at constant temperature. Determine the correct rate law for this reaction.

Correct Answer
verified

The compound RX₃ decomposes according to the equation 3RX₃  R + R₂X₃+ 3X₂ In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of reaction over the entire experiment?

Correct Answer
verified

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

Correct Answer
verified

Briefly outline the key arguments in the collision theory of reaction rates for the elementary reaction C + D  products Show that this theory predicts a second-order rate law, and how it predicts the form of the rate constant k.

Correct Answer
verified
For reaction to occur, the molecules mus...
View Answer

Correct Answer
verified
a. z is a collision rate constant, such ...
View Answer

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year^-1. What fraction of the tritium initially in a sample is still present 30 years later?

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

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10^-4 mol L^-1 and the rate constant k = 1.08 × 10^-6 s^-1, what concentration of R remains after 25 days?

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
a. 260 ± 2...
View Answer

The rate constant for a reaction is 4.65 L mol^-1s^-1. What is the overall order of the reaction?

Correct Answer
verified

A transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram.

Correct Answer
verified

For the reaction 2A + B + 2C  D + E The following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.

Correct Answer
verified

In going from room temperature (25.0 °C) to 10 °C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

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 for the reaction 3A  C is Rate = 4.36 × 10^-2 L mol^-1hr^-1[A]² What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Correct Answer
verified

The reaction CH₃NC(g)  CH₃CN(g) is first-order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min^-1?

Correct Answer
verified

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

Correct Answer
verified

A catalyst accelerates a reaction because

Correct Answer
verified

Briefly list the features/properties common to all catalysts and how they work. Draw a labeled reaction energy diagram as part of your answer.

Correct Answer
verified
Catalysts speed up a reaction ...
View Answer

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

For the reaction 3A(g) + 2B(g)  2C(g) + 2D(g) The following data were collected at constant temperature. Determine the correct rate law for this reaction.

Correct AnswerverifiedShow Answer

The compound RX3 decomposes according to the equation 3RX3  R + R2X3 + 3X2 In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of reaction over the entire experiment?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Briefly outline the key arguments in the collision theory of reaction rates for the elementary reaction C + D  products Show that this theory predicts a second-order rate law, and how it predicts the form of the rate constant k.

Correct AnswerverifiedFor reaction to occur, the molecules mus...View AnswerShow Answer

In the collision theory of reaction rates, the rate constant for a bimolecular reaction can be written as k = zpexp(-Ea/RT) In one sentence each, clearly explain the physical meaning (interpretation) of the following three factors which appear in the above expression: a. z b. p c. exp(-Ea/RT)

Correct Answerverifieda. z is a collision rate constant, such ...View AnswerShow Answer

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year-1. What fraction of the tritium initially in a sample is still present 30 years later?

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

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10-4 mol L-1 and the rate constant k = 1.08 × 10-6 s-1, what concentration of R remains after 25 days?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answerverifieda. 260 ± 2...View AnswerShow Answer

The rate constant for a reaction is 4.65 L mol-1s-1. What is the overall order of the reaction?

Correct AnswerverifiedShow Answer

A transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram.

Correct AnswerverifiedShow Answer

For the reaction 2A + B + 2C  D + E The following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.

Correct AnswerverifiedShow Answer

In going from room temperature (25.0 °C) to 10 °C above room temperature, the rate of a reaction doubles. Calculate the activation energy for the reaction.

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 for the reaction 3A  C is Rate = 4.36 × 10-2 L mol-1 hr-1[A]2 What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Correct AnswerverifiedShow Answer

The reaction CH3NC(g)  CH3CN(g) is first-order with respect to methyl isocyanide, CH3NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min-1?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A catalyst accelerates a reaction because

Correct AnswerverifiedShow Answer

Briefly list the features/properties common to all catalysts and how they work. Draw a labeled reaction energy diagram as part of your answer.

Correct AnswerverifiedCatalysts speed up a reaction ...View AnswerShow Answer

Correct Answer
verified

The compound RX₃ decomposes according to the equation 3RX₃  R + R₂X₃+ 3X₂ In an experiment the following data were collected for the decomposition at 100°C. What is the average rate of reaction over the entire experiment?

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
For reaction to occur, the molecules mus...
View Answer

Correct Answer
verified
a. z is a collision rate constant, such ...
View Answer

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year^-1. What fraction of the tritium initially in a sample is still present 30 years later?

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

A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10^-4 mol L^-1 and the rate constant k = 1.08 × 10^-6 s^-1, what concentration of R remains after 25 days?

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
a. 260 ± 2...
View Answer

The rate constant for a reaction is 4.65 L mol^-1s^-1. What is the overall order of the reaction?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The rate law for the reaction 3A  C is Rate = 4.36 × 10^-2 L mol^-1hr^-1[A]² What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Correct Answer
verified

The reaction CH₃NC(g)  CH₃CN(g) is first-order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min^-1?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Catalysts speed up a reaction ...
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