Question 1

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?

Accepted Answer

The integrated rate law for a first-order reaction is:ln[A]t=−kt+ln[A]0where [A]t is the concentration of the reactant at time t, k is the rate constant, and [A]0 is the initial concentration of the reactant.Substituting the given values into the integrated rate law, we get:ln[CH3NC]t=−(0.46s−1)(0.20min)(60smin)+ln(0.10M)ln[CH3NC]t=−5.52+ln(0.10M)ln[CH3NC]t=−4.62[CH3NC]t=e−4.62=4.0×10−4M

Question 2

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?

Accepted Answer

For a first-order reaction, the time it takes for the concentration to fall to a certain percentage of its initial value can be calculated using the formula $t = \frac{\ln(\frac{[A]_0}{[A]})}{k}$, where $[A]_0$ is the initial concentration, $[A]$ is the final concentration, and $k$ is the rate constant. Falling to 12.5% of its initial value means the concentration falls to $\frac{1}{8}$ of its initial value, which corresponds to 3 half-lives ($2^3 = 8$). Since the half-life is 8.75 hours, the total time is $3 \times 8.75 = 26.25$ hours, which is approximately 26.2 hours.

Question 3

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?

Accepted Answer

The concentration of cyclopropane decreases exponentially with time, which suggests a first-order reaction. First-order reactions have a constant rate that is proportional to the concentration of only one reactant. Therefore, the order of the reaction with respect to cyclopropane is first.

Question 4

The data below were collected for the following reaction: 2 NO₂ (g)+ F₂ (g)2 NO₂F (g) What is the expression for the rate law of the reaction?

Accepted Answer

The rate law expresses the dependence of the rate of a chemical reaction on the concentration of the reactants. Based on the data given, the rate of the reaction depends on the concentrations of both NO₂ and F₂, and the order of each reactant is 1. Therefore, the expression for the rate law can be written as Rate = k[NO₂][F₂]. Option A is the only choice that matches this expression. Option B and C introduce an extra term that is not supported by the data, and option D does not include the dependence on F₂ concentration. Therefore, the best choice is A.

Question 5

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?

Accepted Answer

The half-life of a first-order reaction is independent of initial concentration. Therefore, the fact that the half-life of this reaction is independent of the concentration of H₂O₂(aq) suggests that this reaction follows first-order kinetics.

Question 6

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?

Accepted Answer

The formula for calculating the half-life of a first-order reaction is:

t1/2 = (ln 2)/k

where k is the rate constant.

Plugging in the given value of k, we get:

t1/2 = (ln 2)/4.2 × 10-14 s-1

Using a calculator, we get:

t1/2 = 1.67 × 10^13 s

This can be expressed in scientific notation as:

t1/2 = 1.7 × 10^13 s

Therefore, the best choice is C: 1.7 × 10^13 s.

Question 7

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?

Accepted Answer

The first-order decomposition of hydrogen peroxide is a pseudo-first order reaction, as the concentration of water is much greater than that of hydrogen peroxide. This means that the rate of the reaction is dependent only on the concentration of hydrogen peroxide.

The integrated rate law for a pseudo-first order reaction is:

ln([A]t/[A]0) = -kt

Where [A]t is the concentration of hydrogen peroxide at time t, [A]0 is the initial concentration of hydrogen peroxide, k is the rate constant, and t is time.

Taking the natural logarithm of the concentration of hydrogen peroxide and plotting it versus time will produce a straight line. Therefore, the best choice is D.

Question 8

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?

Accepted Answer

The answer of The following reaction is first order: C₂H₆...

Question 9

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?

Accepted Answer

The rate law is determined by the method of initial rates, which involves comparing the initial rates of the reaction at different concentrations of the reactants. From the given data, we can infer that the initial rate depends on the concentrations of [S₂O₈^2-] and [I^-]. Therefore, the correct rate law should include both of these reactants to the first power. The other reactants, ⁵ and ², do not affect the initial rate of the reaction and are not included in the rate law. Therefore, the only correct choice is A.

Question 10

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?

Accepted Answer

The answer of The following set of data was obtained...

Question 11

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?

Accepted Answer

For a first-order reaction, the rate constant $k$ can be calculated using the formula $k = \frac{0.693}{t_{1/2}}$, where $t_{1/2}$ is the half-life of the reaction. Substituting $t_{1/2} = 530$ seconds into the formula gives $k = \frac{0.693}{530} \approx 1.3 \times 10^{-3} s^{-1}$.

Question 12

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?

Accepted Answer

For a first-order reaction, the formula is ln([A]₀/[A]) = kt. Plugging in the values: ln([A]₀/[A]) = (2.20 × 10⁻⁵ s⁻¹)(7200 s). Solving for [A]/[A]₀ gives approximately 0.854, meaning 85.4% remains.

Question 13

A zeroth order reaction is one whose

Accepted Answer

A zeroth order reaction is one whose rate is independent of reactant concentration. This means that the rate of reaction remains constant, regardless of how much reactant is present. Therefore, the rate law equation for a zeroth order reaction is of the form rate = k, where k is the rate constant.

Question 14

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

Accepted Answer

For a zeroth-order reaction, the rate of reaction is constant and does not depend on the concentration of the reactants. As the reaction proceeds and the concentration of the reactants decreases, the amount of substance halved by the reaction in a given time period also decreases. This means that each half-life is shorter than the previous one, leading to the correct statement that each half-life is half as long as the preceding half-life.

Question 15

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?

Accepted Answer

The integrated rate law for a first-order reaction is:

ln([A]t/[A]0) = -kt

where [A]t is the concentration of A at time t, [A]0 is the initial concentration of A, k is the rate constant, and t is the time.

We are given the rate constant k = 0.76 s^-1 and we want to find the time it takes for [A]t/[A]0 = 0.42.

Substituting the given values into the integrated rate law, we get:

ln(0.42) = -0.76t

Solving for t, we get:

t = ln(0.42)/(-0.76)

t ≈ 1.1 s

Therefore, the answer is choice B.

Question 16

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.

Accepted Answer

The answer of The following set of data was obtained...

Question 17

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^-?

Accepted Answer

The answer of The following set of data was obtained...

Question 18

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?

Accepted Answer

The answer of The following set of data was obtained...

Question 19

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

The rate law for this reaction can be written as rate = k[H₃C] [OH^-]. Since the question states that this data was obtained by the method of initial rates, it means that the initial concentration of each reactant is different in each experiment, but the time taken for the reaction to reach a certain point is the same. Therefore, we can compare the initial rates of the reaction in different experiments and find the value of k. From the given data, it can be observed that when [H₃C] is kept constant and [OH^-] is doubled, the initial rate of the reaction is also doubled. Therefore, the order of the reaction with respect to [OH^-] is 1. Similarly, when [OH^-] is kept constant and [H₃C] is doubled, the initial rate of the reaction is quadrupled. Therefore, the order of the reaction with respect to [H₃C] is 2. Using these orders, we can calculate the value of k as 4.4 × 10^-4 s^-1. Hence, the correct answer is option B.

Question 20

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?

Accepted Answer

The answer of For a particular first-order reaction,it takes 48...

Quiz 13: Chemical Kinetics

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?

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?

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?

The data below were collected for the following reaction: 2 NO₂ (g) + F₂ (g) 2 NO₂F (g) What is the expression for the rate law of the reaction?

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?

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?

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?

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?

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?

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?

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?

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 zeroth order reaction is one whose

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

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?

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.

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^-?

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?

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?

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?

Quiz 13: Chemical Kinetics

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?

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?

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?

The data below were collected for the following reaction: 2 NO2 (g) + F2 (g) 2 NO2F (g) What is the expression for the rate law of the reaction?

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?

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?

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?

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?

The following set of data was obtained by the method of initial rates for the reaction: S2O82-(aq) + 3 I-(aq) → 2 SO42-(aq) + I3-(aq) What is the rate law for the reaction?

The following set of data was obtained by the method of initial rates for the reaction: S2O82-(aq) + 3 I-(aq) → 2 SO42-(aq) + I3-(aq) What is the initial rate when S2O82- is 0.15 M and I- is 0.15 M?

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?

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 zeroth order reaction is one whose

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

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?

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.

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-?

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?

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?

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?

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?

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?

The data below were collected for the following reaction: 2 NO₂ (g) + F₂ (g) 2 NO₂F (g) What is the expression for the rate law of the reaction?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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.

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^-?

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?

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?

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?