Question 1

kJ/mol. Sn²⁺ + 2Co³⁺ → Sn₄⁺ + 2Co²⁺ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

Accepted Answer

The rate constant increases by a factor determined by the Arrhenius equation. The temperature change from 10°C to 28°C results in a significant increase in the rate constant, calculated to be approximately 4.6 times.

Question 2

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

Accepted Answer

The fraction remaining can be calculated using the first-order decay formula: N/N0 = e^(-kt). Substituting k = 0.056 yr^-1 and t = 30 years, we get N/N0 = e^(-0.056*30) ≈ 0.19.

Question 3

The rate law for the reaction H₂O₂ + 2H⁺ + 2I^- → I₂ + 2H₂O is rate = k[H₂O₂][I^-].The following mechanism has been suggested. H₂O₂ + I^- → HOI + OH^- (slow) OH^- + H⁺ → H₂O (fast) HOI + H⁺ + I^- → I₂ + H₂O (fast) Identify all intermediates included in this mechanism.

Accepted Answer

The intermediates in this mechanism are HOI and OH^-, which are both included in reaction step (1) and participate in subsequent steps of the mechanism. The other species (H⁺, I^-, and H₂O) are either reactants or products in the given mechanism.

Question 4

The activation energy for the following first-order reaction is 102 kJ/mol. N₂O₅(g)→ 2NO₂(g)+ (1/2)O₂(g) The value of the rate constant (k)is 1.35 × 10^-4 s^-1 at 35°C.What is the value of k at 0°C? (R =8.314 J/mol• K)

Accepted Answer

The answer of The activation energy for the following first-order...

Question 5

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

Since the reaction is first-order with respect to methyl isocyanide, we can use the first-order integrated rate law: [CH₃NC]t = [CH₃NC]0 e-k t, where [CH₃NC]t is the concentration of CH₃NC at time t, [CH₃NC]0 is the initial concentration of CH₃NC, k is the rate constant, and t is time. Let's consider the given information, "it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react". That means, at t=10.3 min, [CH₃NC]t = 0.75 [CH₃NC]0 Substituting these values in the first-order integrated rate law, we get: 0.75 [CH₃NC]0 = [CH₃NC]0 e-k (10.3 min) Simplifying, we get: k = ln(4/3)/10.3 min ≈ 0.0279 min^-1 Therefore, the answer is B, 0.0279 min^-1.

Question 6

Below is a plot of the reaction of A decomposing to form products.  Based on the figure,which might be the order of the reaction with respect to A?

Accepted Answer

The answer of Below is a plot of the reaction...

Question 7

The following diagram represents the zeroth-order decomposition of A to form X according to the following balanced chemical equation: A → X.Each sphere represents 1.0 mmol of atoms,and the volume of the box is 1.0 L.  What is the half-life of the reaction?

Accepted Answer

The answer of The following diagram represents the zeroth-order decomposition...

Question 8

The isomerization of cyclopropane follows first-order kinetics.The rate constant at 700.K is 6.20 × 10^-4 min^-1,and the half-life at 760.K is 29.0 min.What is the activation energy for this reaction? (R = 8.314 J/mol• K)

Accepted Answer

The answer of The isomerization of cyclopropane follows first-order kinetics.The...

Question 9

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years.What is the first-order rate constant for its decay?

Accepted Answer

The first-order rate constant for radioactive decay can be calculated using the formula:
k = ln(2)/t1/2
where t1/2 is the half-life of the isotope.

In this case, t1/2 = 5730 years, so:
k = ln(2)/5730 = 1.21 × 10-4 yr-1

Therefore, the best choice is B.

Question 10

A rate constant obeys the Arrhenius equation,the factor A being 2.2 × 10¹³ s^-1 and the activation energy being 150.kJ mol^-1.What is the value of the rate constant at 227°C? (R = 8.314 J/mol• K)

Accepted Answer

The answer of A rate constant obeys the Arrhenius equation,the...

Question 11

Consider reactions A,B,and C,which have the potential energy profiles shown.Assuming that the reactions have roughly the same frequency factors,which reaction is the slowest?

Accepted Answer

The answer of Consider reactions A,B,and C,which have the potential...

Question 12

Consider the following potential energy profile for the A → B reaction.How many elementary steps are there?

Accepted Answer

The answer of Consider the following potential energy profile for...

Question 13

What is the molecularity of the following elementary reaction? NHCl₂(aq)+ OH^-(aq)→ NCl₂^-(aq)+ H₂O(l)

Accepted Answer

The reaction involves two reactant molecules (NHCl and OH) coming together to form one product molecule (NClH and H2O). Therefore, the molecularity of the reaction is bimolecular.

Question 14

Consider the following potential energy profile for the A → B reaction.How many intermediates are formed?

Accepted Answer

The answer of Consider the following potential energy profile for...

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

In a first-order reaction, the amount of reactant remaining after n half-lives is given by the formula (1/2)^n. After 4 half-lives, the fraction of the initial reactant remaining is (1/2)^4 = 1/16 = 0.0625. Therefore, the fraction consumed is 1 - 0.0625 = 0.9375, which rounds to 0.94.

Question 16

What is the name given to the slowest step in the mechanism of a reaction?

Accepted Answer

The rate-determining step is the slowest step in a reaction mechanism and limits the overall rate of the reaction.

Question 17

Consider the following potential energy profile for the A → B reaction.The overall reaction is________.

Accepted Answer

The answer of Consider the following potential energy profile for...

Question 18

The isomerization of methyl isocyanide,CH₃NC → CH₃CN,follows first-order kinetics.The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C.Calculate the activation energy for this reaction.(R = 8.314 J/mol • K)

Accepted Answer

The answer of The isomerization of methyl isocyanide,CH₃NC → CH₃CN,follows...

Question 19

Consider the following potential energy profile for the A → B reaction.Assuming that the frequency factor for the reaction is 5.5×10¹⁰ s^-1,what is the rate constant of this first-order reaction at 310 K?

Accepted Answer

The answer of Consider the following potential energy profile for...

Question 20

Enzymes are _______ .

Accepted Answer

Enzymes are biological catalysts, which means they speed up chemical reactions in living organisms without being consumed or altered themselves. They are usually proteins or RNA molecules, and are sensitive to temperature, pH, and other environmental factors.

Quiz 14: Chemical Kinetics

kJ/mol. Sn²⁺ + 2Co³⁺ → Sn₄⁺ + 2Co²⁺ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

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

The activation energy for the following first-order reaction is 102 kJ/mol. N₂O₅(g) → 2NO₂(g) + (1/2) O₂(g) The value of the rate constant (k) is 1.35 × 10^-4 s^-1 at 35°C.What is the value of k at 0°C? (R =8.314 J/mol• K)

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?

Below is a plot of the reaction of A decomposing to form products. Based on the figure,which might be the order of the reaction with respect to A?

The following diagram represents the zeroth-order decomposition of A to form X according to the following balanced chemical equation: A → X.Each sphere represents 1.0 mmol of atoms,and the volume of the box is 1.0 L. What is the half-life of the reaction?

The isomerization of cyclopropane follows first-order kinetics.The rate constant at 700.K is 6.20 × 10^-4 min^-1,and the half-life at 760.K is 29.0 min.What is the activation energy for this reaction? (R = 8.314 J/mol• K)

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years.What is the first-order rate constant for its decay?

A rate constant obeys the Arrhenius equation,the factor A being 2.2 × 10¹³ s^-1 and the activation energy being 150.kJ mol^-1.What is the value of the rate constant at 227°C? (R = 8.314 J/mol• K)

Consider reactions A,B,and C,which have the potential energy profiles shown.Assuming that the reactions have roughly the same frequency factors,which reaction is the slowest?

Consider the following potential energy profile for the A → B reaction.How many elementary steps are there?

What is the molecularity of the following elementary reaction? NHCl₂(aq) + OH^-(aq) → NCl₂^-(aq) + H₂O(l)

Consider the following potential energy profile for the A → B reaction.How many intermediates are formed?

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

What is the name given to the slowest step in the mechanism of a reaction?

Consider the following potential energy profile for the A → B reaction.The overall reaction is________.

The isomerization of methyl isocyanide,CH₃NC → CH₃CN,follows first-order kinetics.The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C.Calculate the activation energy for this reaction.(R = 8.314 J/mol • K)

Consider the following potential energy profile for the A → B reaction.Assuming that the frequency factor for the reaction is 5.5×10¹⁰ s^-1,what is the rate constant of this first-order reaction at 310 K?

Enzymes are _______ .

Quiz 14: Chemical Kinetics

kJ/mol. Sn2+ + 2Co3+ → Sn4+ + 2Co2+ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

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

The rate law for the reaction H2O2 + 2H+ + 2I- → I2 + 2H2O is rate = k[H2O2][I-].The following mechanism has been suggested. H2O2 + I- → HOI + OH- (slow) OH- + H+ → H2O (fast) HOI + H+ + I- → I2 + H2O (fast) Identify all intermediates included in this mechanism.

The activation energy for the following first-order reaction is 102 kJ/mol. N2O5(g) → 2NO2(g) + (1/2) O2(g) The value of the rate constant (k) is 1.35 × 10-4 s-1 at 35°C.What is the value of k at 0°C? (R =8.314 J/mol• K)

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?

Below is a plot of the reaction of A decomposing to form products. Based on the figure,which might be the order of the reaction with respect to A?

The following diagram represents the zeroth-order decomposition of A to form X according to the following balanced chemical equation: A → X.Each sphere represents 1.0 mmol of atoms,and the volume of the box is 1.0 L. What is the half-life of the reaction?

The isomerization of cyclopropane follows first-order kinetics.The rate constant at 700.K is 6.20 × 10-4 min-1,and the half-life at 760.K is 29.0 min.What is the activation energy for this reaction? (R = 8.314 J/mol• K)

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years.What is the first-order rate constant for its decay?

A rate constant obeys the Arrhenius equation,the factor A being 2.2 × 1013 s-1 and the activation energy being 150.kJ mol-1.What is the value of the rate constant at 227°C? (R = 8.314 J/mol• K)

Consider reactions A,B,and C,which have the potential energy profiles shown.Assuming that the reactions have roughly the same frequency factors,which reaction is the slowest?

Consider the following potential energy profile for the A → B reaction.How many elementary steps are there?

What is the molecularity of the following elementary reaction? NHCl2(aq) + OH-(aq) → NCl2-(aq) + H2O(l)

Consider the following potential energy profile for the A → B reaction.How many intermediates are formed?

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

What is the name given to the slowest step in the mechanism of a reaction?

Consider the following potential energy profile for the A → B reaction.The overall reaction is________.

The isomerization of methyl isocyanide,CH3NC → CH3CN,follows first-order kinetics.The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C.Calculate the activation energy for this reaction.(R = 8.314 J/mol • K)

Consider the following potential energy profile for the A → B reaction.Assuming that the frequency factor for the reaction is 5.5×1010 s-1,what is the rate constant of this first-order reaction at 310 K?

Enzymes are _______ .

kJ/mol. Sn²⁺ + 2Co³⁺ → Sn₄⁺ + 2Co²⁺ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

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

The activation energy for the following first-order reaction is 102 kJ/mol. N₂O₅(g) → 2NO₂(g) + (1/2) O₂(g) The value of the rate constant (k) is 1.35 × 10^-4 s^-1 at 35°C.What is the value of k at 0°C? (R =8.314 J/mol• K)

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?

The isomerization of cyclopropane follows first-order kinetics.The rate constant at 700.K is 6.20 × 10^-4 min^-1,and the half-life at 760.K is 29.0 min.What is the activation energy for this reaction? (R = 8.314 J/mol• K)

A rate constant obeys the Arrhenius equation,the factor A being 2.2 × 10¹³ s^-1 and the activation energy being 150.kJ mol^-1.What is the value of the rate constant at 227°C? (R = 8.314 J/mol• K)

What is the molecularity of the following elementary reaction? NHCl₂(aq) + OH^-(aq) → NCl₂^-(aq) + H₂O(l)

The isomerization of methyl isocyanide,CH₃NC → CH₃CN,follows first-order kinetics.The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C.Calculate the activation energy for this reaction.(R = 8.314 J/mol • K)

Consider the following potential energy profile for the A → B reaction.Assuming that the frequency factor for the reaction is 5.5×10¹⁰ s^-1,what is the rate constant of this first-order reaction at 310 K?