Question 1

When the reaction A → B + C is studied,a plot 1/[A]t vs.time gives a straight line with a positive slope.What is the order of the reaction with respect to A?

Accepted Answer

A plot of 1/[A]t vs. time that results in a straight line indicates a second-order reaction with respect to A.

Question 2

What statement below best describes the graph representing the integrated first-order rate law?

Accepted Answer

The integrated first-order rate law can be expressed as ln[A]t = -kt + ln[A]0. Therefore, a plot of ln[A]t on the y-axis and t on the x-axis should yield a straight line with a negative slope equal to -k. Choice A describes a plot of [A]t vs. t, which would not yield a straight line. Choice B describes a plot of 1/[A]t vs. t, which would yield a straight line but with a positive slope equal to k. Choice C describes a plot of ln[A]t vs. t, which is correct in terms of the dependent and independent variables but has the wrong slope. Choice E describes a plot of 1/[A]t vs. t, which would yield a straight line but with a positive slope equal to k.

Question 3

A first-order reaction has a rate constant of 7.5 × 10^-3 s^-1.The time required for the reaction to be 60% complete is?

Accepted Answer

The answer of A first-order reaction has a rate constant...

Question 4

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C.How long will it take for the reaction to be 90% complete?

Accepted Answer

The answer of It takes 42.0 min for the concentration...

Question 5

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is the half-life of the reaction?

Accepted Answer

The answer of A certain first-order reaction A → B...

Question 6

Which is the correct unit for a zeroth-order rate constant?

Accepted Answer

The answer of Which is the correct unit for a...

Question 7

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is its rate constant?

Accepted Answer

The answer of A certain first-order reaction A → B...

Question 8

Cyclopropane is converted to propene in a first-order process.The rate constant is 5.4 × 10^-2h^-1.If the initial concentration of cyclopropane is 0.150 M,what will its concentration be after 22.0 hours?

Accepted Answer

The rate law for the reaction is given as:
Rate = k[Cyclopropane]
The integrated rate law for a first-order reaction is:
ln[A]t = -kt + ln[A]0
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.
Substituting the given values:
ln[Cyclopropane]t = -k*t + ln[Cyclopropane]0
ln[Cyclopropane]t = -(5.4*10^-2)*(22.0) + ln[0.150]
ln[Cyclopropane]t = -1.188 + ln[0.150]
ln[Cyclopropane]t = -0.779
[Cyclopropane]t = e^-0.779
[Cyclopropane]t = 0.46 M
Rounding off the value to two significant figures, we get:
[Cyclopropane]t = 0.046 M
Therefore, the best choice is A, with the concentration of cyclopropane after 22.0 hours being 0.046 M.

Question 9

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 with respect to A?

Accepted Answer

If the plot of ln[A]t vs. time gives a straight line with a negative slope, this indicates that the reaction is first order with respect to A. This is because the integrated rate law for a first order reaction is:

ln[A]t = -kt + ln[A]0

where [A]t and [A]0 are the concentrations of A at time t and at t=0, respectively, k is the rate constant, and t is the reaction time. This equation describes a straight line with a negative slope when ln[A]t is plotted against time.

Question 10

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

The ratio of rates is given by: (rate2)/(rate1) = k[A]2[B]2² / k[A]1[B]1² Canceling out the rate constant and substituting the given concentrations, we get: (rate2)/(rate1) = (0.30 mol/L)2(0.30 mol/L)² / (0.10 mol/L)2(0.10 mol/L)² Simplifying the expression gives: (rate2)/(rate1) = 27 Therefore, the answer is E) 27.

Question 11

What statement below best describes the graph representing the integrated second-order rate law?

Accepted Answer

For a second-order reaction, the integrated rate law can be represented as 1/[A] = kt + 1/[A]₀, where [A] is the concentration of the reactant at time t, [A]₀ is the initial concentration, and k is the rate constant. Plotting 1/[A] versus time (t) yields a straight line with a positive slope equal to the rate constant k.

Question 12

Which of the following is the correct unit for a second-order rate constant?

Accepted Answer

The answer of Which of the following is the correct...

Question 13

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

Accepted Answer

According to the given information, the slope of the ln[sucrose] vs. time graph is -0.208 h^-1. This represents the rate constant of the reaction, k. Therefore, the rate law can be expressed as Rate = k[sucrose]. Since the question does not provide any information about the order of the reaction, it is safe to assume that it is a first-order reaction, and the rate law simplifies to Rate = k[sucrose]. Option B is the only one that matches this simplified rate law.

Question 14

The first-order reaction SO₂Cl₂→ SO₂ + Cl₂ is 10% complete in 80.min.How long would it take for the reaction to be 95% complete?

Accepted Answer

The answer of The first-order reaction SO₂Cl₂→ SO₂ + Cl₂...

Question 15

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10^-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

Accepted Answer

We can use the first-order integrated rate law to solve for the remaining concentration:

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

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

We can rearrange this equation to solve for [A]t:

[A]t = [A]0 * e^(-kt)

Substituting the given values:

[A]t = (0.0314 M) * e^(-6.40 × 10^-3 min^-1 * 62.0 min)

[A]t = 2.11 × 10^-2 M

Therefore, the concentration that will remain after 62.0 min is 2.11 × 10^-2 M. The correct answer is D.

Question 16

Nitric oxide gas (NO)reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl₂ (M)

Accepted Answer

The answer of Nitric oxide gas (NO)reacts with chlorine gas...

Question 17

Ammonium cyanate (NH₄CNO)reacts to form urea (N H₂CON H₂).At 65°C the rate constant,k,is 3.60 L • mol^-1 • s^-1.What is the rate law for this reaction?

Accepted Answer

The rate law is determined by the experimental data, which shows that the rate of the reaction is proportional to the concentration of ammonium cyanate raised to the first power. Therefore, the rate law can be written as Rate = k[NH4NCO], where k is the rate constant. However, the question specifies that urea is formed by the reaction, not ammonium cyanate. Since the stoichiometry of the reaction shows that one mole of ammonium cyanate produces one mole of urea, the rate law can be written as Rate = k[NH4NCO][urea], or equivalently Rate = k[NH4NCO][NH2CONH2]. The correct choice is B, which is the only option that includes both [NH4NCO] and [NH2CONH2] in the rate law.

Question 18

Tetrafluoroethylene,C₂F₄,can be converted to octafluorocyclobutane,which can be used as a refrigerant or an aerosol propellant.A plot of 1/[C₂F₄] vs.time gives a straight line with a slope of 0.0448 L •mol^-1 • s^-1.What is the rate law for this reaction?

Accepted Answer

The answer of Tetrafluoroethylene,C₂F₄,can be converted to octafluorocyclobutane,which can be...

Question 19

What is the activation energy for a reaction if k = 1.89 × 10^-8 s^-1 at 540.K and k = 2.45 × 10^-7s^-1 at 601 K?

Accepted Answer

We can use the Arrhenius equation, k = A*exp(-Ea/RT) where, k = rate constant A = pre-exponential factor Ea = activation energy R = gas constant T = temperature Taking the natural logarithm of both sides, ln(k) = ln(A) - Ea/RT We can rearrange this equation as follows to solve for Ea, ln(k1/k2) = (Ea/R)(1/T2 - 1/T1) Substituting the given values, ln(1.89 × 10^-8/2.45 × 10^-7) = (Ea/8.314)(1/601 - 1/540) Simplifying this gives, Ea = -8.314*(1/601 - 1/540)*ln(1.89 × 10^-8/2.45 × 10^-7) Evaluating this equation gives Ea = 113 kJ/mol. Therefore, the answer is choice A.

Question 20

What is defined as the minimum amount of energy required to initiate a chemical reaction?

Accepted Answer

The minimum amount of energy required to initiate a chemical reaction is called activation energy. Choice A, collision energy, refers to the energy required to bring reactant molecules together for a reaction to occur. Choice B, effective collision energy, refers to the energy required for a collision between reactant molecules to result in a successful reaction. Choice C, reaction energy, refers to the overall energy change during a chemical reaction (i.e. the difference in energy between the starting materials and the products). Choice E, rate energy, is not a commonly used term in chemistry and does not relate to the concept of activation energy.

Quiz 14: Chemical Kinetics

When the reaction A → B + C is studied,a plot 1/[A]t vs.time gives a straight line with a positive slope.What is the order of the reaction with respect to A?

What statement below best describes the graph representing the integrated first-order rate law?

A first-order reaction has a rate constant of 7.5 × 10^-3 s^-1.The time required for the reaction to be 60% complete is?

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C.How long will it take for the reaction to be 90% complete?

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is the half-life of the reaction?

Which is the correct unit for a zeroth-order rate constant?

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is its rate constant?

Cyclopropane is converted to propene in a first-order process.The rate constant is 5.4 × 10^-2h^-1.If the initial concentration of cyclopropane is 0.150 M,what will its concentration be after 22.0 hours?

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 with respect to A?

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) ?

What statement below best describes the graph representing the integrated second-order rate law?

Which of the following is the correct unit for a second-order rate constant?

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

The first-order reaction SO₂Cl₂→ SO₂ + Cl₂ is 10% complete in 80.min.How long would it take for the reaction to be 95% complete?

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10^-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

Nitric oxide gas (NO) reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl₂ (M)

Ammonium cyanate (NH₄CNO) reacts to form urea (N H₂CON H₂) .At 65°C the rate constant,k,is 3.60 L • mol^-1 • s^-1.What is the rate law for this reaction?

Tetrafluoroethylene,C₂F₄,can be converted to octafluorocyclobutane,which can be used as a refrigerant or an aerosol propellant.A plot of 1/[C₂F₄] vs.time gives a straight line with a slope of 0.0448 L •mol^-1 • s^-1.What is the rate law for this reaction?

What is the activation energy for a reaction if k = 1.89 × 10^-8 s^-1 at 540.K and k = 2.45 × 10^-7s^-1 at 601 K?

What is defined as the minimum amount of energy required to initiate a chemical reaction?

Quiz 14: Chemical Kinetics

When the reaction A → B + C is studied,a plot 1/[A]t vs.time gives a straight line with a positive slope.What is the order of the reaction with respect to A?

What statement below best describes the graph representing the integrated first-order rate law?

A first-order reaction has a rate constant of 7.5 × 10-3 s-1.The time required for the reaction to be 60% complete is?

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C.How long will it take for the reaction to be 90% complete?

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is the half-life of the reaction?

Which is the correct unit for a zeroth-order rate constant?

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is its rate constant?

Cyclopropane is converted to propene in a first-order process.The rate constant is 5.4 × 10-2 h-1.If the initial concentration of cyclopropane is 0.150 M,what will its concentration be after 22.0 hours?

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 with respect to A?

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) ?

What statement below best describes the graph representing the integrated second-order rate law?

Which of the following is the correct unit for a second-order rate constant?

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

The first-order reaction SO2Cl2→ SO2 + Cl2 is 10% complete in 80.min.How long would it take for the reaction to be 95% complete?

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

Nitric oxide gas (NO) reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl2 (M)

Ammonium cyanate (NH4CNO) reacts to form urea (N H2CON H2) .At 65°C the rate constant,k,is 3.60 L • mol-1 • s-1.What is the rate law for this reaction?

Tetrafluoroethylene,C2F4,can be converted to octafluorocyclobutane,which can be used as a refrigerant or an aerosol propellant.A plot of 1/[C2F4] vs.time gives a straight line with a slope of 0.0448 L •mol-1 • s-1.What is the rate law for this reaction?

What is the activation energy for a reaction if k = 1.89 × 10-8 s-1 at 540.K and k = 2.45 × 10-7 s-1 at 601 K?

What is defined as the minimum amount of energy required to initiate a chemical reaction?

A first-order reaction has a rate constant of 7.5 × 10^-3 s^-1.The time required for the reaction to be 60% complete is?

Cyclopropane is converted to propene in a first-order process.The rate constant is 5.4 × 10^-2h^-1.If the initial concentration of cyclopropane is 0.150 M,what will its concentration be after 22.0 hours?

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) ?

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

The first-order reaction SO₂Cl₂→ SO₂ + Cl₂ is 10% complete in 80.min.How long would it take for the reaction to be 95% complete?

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10^-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

Nitric oxide gas (NO) reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl₂ (M)

Ammonium cyanate (NH₄CNO) reacts to form urea (N H₂CON H₂) .At 65°C the rate constant,k,is 3.60 L • mol^-1 • s^-1.What is the rate law for this reaction?

Tetrafluoroethylene,C₂F₄,can be converted to octafluorocyclobutane,which can be used as a refrigerant or an aerosol propellant.A plot of 1/[C₂F₄] vs.time gives a straight line with a slope of 0.0448 L •mol^-1 • s^-1.What is the rate law for this reaction?

What is the activation energy for a reaction if k = 1.89 × 10^-8 s^-1 at 540.K and k = 2.45 × 10^-7s^-1 at 601 K?