Question 1

Calculate the temperature if a reaction has a rate constant, k, of 21.3 s^-1, a frequency factor, A, of 7.98 × 10¹³ s^-1, and an activation energy, E_a, of 102 kJ mol^-1.

Accepted Answer

The answer of Calculate the temperature if a reaction has...

Question 2

A reaction is found to have an activation energy of 108 kJ mol^-1. If the rate constant for this reaction is 4.60 × 10^-6 s^-1 at 275 K, what is the rate constant at 366 K?

Accepted Answer

The answer of A reaction is found to have an...

Question 3

Calculate the frequency factor, A, for a reaction with a rate constant of 7834 s^-1 and an activation energy, E_a, of 68.4 kJ mol^-1 at 305 K.

Accepted Answer

The frequency factor can be calculated using the Arrhenius equation: k = A * exp(-Ea/RT).
At 305 K, we have:
7834 = A * exp(-68400/(8.314*305))
Solving for A, we get:
A = 4.1 × 10^15 s^-1

Question 4

Calculate the activation energy, E_a, for a reaction with a frequency factor, A, of 6.10 × 10¹⁴ s^-1 and a rate constant of 13.0 s^-1 at 320 K.

Accepted Answer

We can use the Arrhenius equation: 
k = A * exp(-Ea/RT)
where k is the rate constant, A is the frequency factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.
Plugging in the given values: 
13.0 s-1 = 6.10 × 10^14 s-1 * exp(-Ea/(8.314 J/mol*K * 320 K))
Simplifying: 
ln(13.0 s-1/6.10 × 10^14 s-1) = -Ea/(8.314 J/mol*K * 320 K)
-31.5 = -Ea/(2.65 J/mol)
Ea = 83.8 kJ/mol. 
Therefore, the correct answer is B.

Question 5

Calculate the frequency factor, A, for a reaction with a rate constant of 6.3 × 10³ s^-1 and an activation energy, E_a, of 74 kJ mol^-1 at 315 K.

Accepted Answer

The answer of Calculate the frequency factor, A, for a...

Question 6

If the activation energy for a given compound is found to be 42.0 kJ mol^-1 with a frequency factor of 8.0 × 10¹⁰ s^-1, what is the rate constant for this reaction at 298 K?

Accepted Answer

The answer of If the activation energy for a given...

Question 7

Which rate law is termolecular?

Accepted Answer

The answer of Which rate law is termolecular?
...

Question 8

If the activation energy for a given compound is found to be 103 kJ mol^-1 with a frequency factor of 4.0 × 10¹³ s^-1, what is the rate constant for this reaction at 398 K?

Accepted Answer

The answer of If the activation energy for a given...

Question 9

The first-order rearrangement of CH₃NC is measured to have a rate constant of 3.61 × 10^-15 s^-1 at 298 K and a rate constant of 8.66 × 10^-7 s^-1 at 425 K. Determine the activation energy for this reaction.

Accepted Answer

The answer of The first-order rearrangement of CH₃NC is measured...

Question 10

Calculate the activation energy, E_a, for a reaction with a frequency factor, A, of 8.12 × 10⁹ s^-1 and a rate constant of 3.05 × 10⁴ s^-1 at 375 K.

Accepted Answer

The Arrhenius equation relates the rate constant of a reaction to the activation energy and the temperature:

k = A * exp(-Ea/RT)

where k is the rate constant, A is the frequency factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvins.

Rearranging this equation, we get:

ln(k/A) = (-Ea/R) * (1/T)

This gives us a linear relationship between ln(k/A) and 1/T, with a slope of -Ea/R. We can use this relationship to determine the activation energy from experimental data.

Using the given values:

A = 8.12 × 10^19 s^-1
k = 3.05 × 10^14 s^-1
T = 375 K

We can calculate ln(k/A):

ln(k/A) = ln(3.05 × 10^14/8.12 × 10^19) = -64.89

Now, we can use the slope of the ln(k/A) vs 1/T graph to determine the activation energy:

slope = -Ea/R

We know the gas constant, R, to be 8.314 J/mol*K. Converting the units of the slope to J/mol*K gives:

slope = -64.89 / (1/375) = -24313.5 J/mol*K

Now we can solve for Ea:

Ea = -slope * R = 203034.7 J/mol

Converting to kJ/mol gives:

Ea = 203.0 kJ/mol

So the answer is approximately 38.9 kJ/mol, which is choice B.

Question 11

Calculate the temperature if a reaction has a rate constant, k, of 1234 s^-1, a frequency factor, A, of 1.34 × 10¹⁴ s^-1, and an activation energy, E_a, of 79.6 kJ mol^-1.

Accepted Answer

The answer of Calculate the temperature if a reaction has...

Question 12

Which of the following reactions would you predict to have the largest orientation factor?

Accepted Answer

The answer of Which of the following reactions would you...

Question 13

Which rate law is bimolecular?

Accepted Answer

A bimolecular rate law has two reactant species involved in the rate determining step. Choice B is the only option with two reactants, [A] and [B].

Question 14

Calculate the frequency factor, A, for a reaction with a rate constant of 162.3 s^-1 and an activation energy, E_a, of 68 kJ mol^-1 at 298 K.

Accepted Answer

The answer of Calculate the frequency factor, A, for a...

Question 15

A reaction is found to have an activation energy of 38.0 kJ mol^-1. If the rate constant for this reaction is 1.60 × 10² L mol^-1s^-1 at 249 K, what is the rate constant at 436 K?

Accepted Answer

Using the Arrhenius equation, 
ln(k2/k1) = (Ea/R)[(1/T1) - (1/T2)]
ln(k2/1.60 × 10^-12 L mol^-1 s^-1) = (38.0 kJ mol^-1/8.314 J mol^-1 K^-1)[(1/249 K) - (1/436 K)]
ln(k2/1.60 × 10^-12 L mol^-1 s^-1) = 14.292
k2/1.60 × 10^-12 L mol^-1 s^-1 = e^14.292
k2 = 4.20 × 10^15 L mol^-1 s^-1 
Therefore, the best answer choice is D.

Question 16

Calculate the activation energy, E_a, for a reaction with a frequency factor, A, of 9.3 × 10¹⁰ s^-1 and a rate constant of 1.06 × 10³ s^-1 at 273 K.

Accepted Answer

The answer of Calculate the activation energy, E_a, for a...

Question 17

Calculate the temperature if a reaction has a rate constant, k, of 841 s^-1, a frequency factor, A, of 6.0 × 10¹² s^-1, and an activation energy, E_a, of 62 kJ mol^-1.

Accepted Answer

The temperature can be calculated using the Arrhenius equation:
k = A * e^(-Ea/RT)
where R is the gas constant and T is the temperature in Kelvin. Solving for T:
T = Ea/(R*ln(A/k))
Plugging in the given values:
T = (62 kJ/mol)/(8.314 J/mol/K * ln(6.0x10^12 s^-1/841 s^-1))
T = 330 K, which is closest to choice D.

Question 18

If a reaction carried out at 61 ◦C has an activation energy, E_a, of 67.3 kJ mol^-1, a rate constant of 791 s^-1, and a frequency factor, A, of 2.65 × 10¹³, what is the value of R? k = A

Accepted Answer

The answer of If a reaction carried out at 61...

Question 19

Identify the rate-determining step.

Accepted Answer

The rate-determining step is the slowest step because it is the limiting factor in determining the overall rate of the reaction. The other steps may happen faster, but they cannot occur any faster than the rate-determining step allows.

Question 20

A reaction is found to have a rate constant of 3.36 × 10⁴ L mol^-1s^-1 at 344 K and a rate constant of 7.69 L mol^-1s^-1 at 219 K. Determine the activation energy for this reaction.

Accepted Answer

We can use the Arrhenius equation to solve for the activation energy (Ea):

k1 = A1*e^(-Ea/RT1)
k2 = A2*e^(-Ea/RT2)

where k1 and k2 are the rate constants at temperatures T1 and T2, respectively, and A1 and A2 are the pre-exponential factors or Arrhenius constants.

Taking the natural logarithm of both equations, we get:

ln(k1) = ln(A1) - (Ea/RT1)
ln(k2) = ln(A2) - (Ea/RT2)

Subtracting the second equation from the first, we eliminate ln(A):

ln(k1/k2) = (Ea/R)*[(1/T2) - (1/T1)]

Solving for Ea, we get:

Ea = (R*ln(k1/k2))/[(1/T2) - (1/T1)]

Plugging in the given values, we get:

Ea = (8.314 J/mol*K) * ln(3.36x10^14/7.69) / [(1/219 K) - (1/344 K)]

Ea ≈ 42.0 kJ/mol

Therefore, the best choice is B, with an activation energy of 42.0 kJ/mol.

Quiz 13: Chemical Kinetics

Calculate the temperature if a reaction has a rate constant, k, of 21.3 s-1, a frequency factor, A, of 7.98 × 1013 s-1, and an activation energy, Ea, of 102 kJ mol-1.

A reaction is found to have an activation energy of 108 kJ mol-1. If the rate constant for this reaction is 4.60 × 10-6 s-1 at 275 K, what is the rate constant at 366 K?

Calculate the frequency factor, A, for a reaction with a rate constant of 7834 s-1 and an activation energy, Ea, of 68.4 kJ mol-1 at 305 K.

Calculate the activation energy, Ea, for a reaction with a frequency factor, A, of 6.10 × 1014 s-1 and a rate constant of 13.0 s-1 at 320 K.

Calculate the frequency factor, A, for a reaction with a rate constant of 6.3 × 103 s-1 and an activation energy, Ea, of 74 kJ mol-1 at 315 K.

If the activation energy for a given compound is found to be 42.0 kJ mol-1 with a frequency factor of 8.0 × 1010 s-1, what is the rate constant for this reaction at 298 K?

Which rate law is termolecular?

If the activation energy for a given compound is found to be 103 kJ mol-1 with a frequency factor of 4.0 × 1013 s-1, what is the rate constant for this reaction at 398 K?

The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 × 10-15 s-1 at 298 K and a rate constant of 8.66 × 10-7 s-1 at 425 K. Determine the activation energy for this reaction.

Calculate the activation energy, Ea, for a reaction with a frequency factor, A, of 8.12 × 109 s-1 and a rate constant of 3.05 × 104 s-1 at 375 K.

Calculate the temperature if a reaction has a rate constant, k, of 1234 s-1, a frequency factor, A, of 1.34 × 1014 s-1, and an activation energy, Ea, of 79.6 kJ mol-1.