   Chapter 12, Problem 68AE

Chapter
Section
Textbook Problem

# The reaction ( CH 3 ) 3 CBr   +   OH −   → ( CH 3 ) 3 COH   +   Br − in a certain solvent is first order with respect to (CH3)3CBr and zero order with respect to OH− .In several experiments. The rate constant k was determined at different temperatures. A plot of ln(k) versus 1/T was constructed resulting in a straight line with a slope value of −1.10 × 104 K and y-intercept of 33.5. Assume k has units of s−1a. Determine the activation energy for this reaction.b. Determine the value of the frequency factor A.c. Calculate the value of k at 25°C.

(a)

Interpretation Introduction

Interpretation: The reaction between (CH3)3CBr and OH is given. The reaction is first order with respect to (CH3)3CBr and zero order with respect to OH . The values of slope and y intercept is given from the plot of lnk versus 1/T(K) . The value of activation energy and frequency factor A is to be calculated for the given reaction. Also the value of k for the given temperature is to be calculated.

Concept introduction: A certain threshold energy which is necessary for the reaction to occur is called activation energy.

The relationship between the rate constant and activation energy is given by the Arrhenius equation,

k=AeEaRT

To determine: The value of activation energy for the given reaction.

Explanation

Given

The value of slope is 1.10×104K .

The relationship between the rate constant and temperature is given by the Arrhenius equation.

k=AeEaRT

Where,

• k is the rate constant.
• A is the frequency factor.
• Ea is the activation energy.
• R is the universal gas constant (8.314J/Kmol) .
• T is the absolute temperature.

Take natural log on both the sides in the above expression.

lnk=ln(AeEaRT)lnk=EaR(1T)+lnA (1)

Equation (1) represents an equation of straight line.

Compare this equation with the general equation of straight line,

y=mx+c

Where,

• m is the slope

(b)

Interpretation Introduction

Interpretation: The reaction between (CH3)3CBr and OH is given. The reaction is first order with respect to (CH3)3CBr and zero order with respect to OH . The values of slope and y intercept is given from the plot of lnk versus 1/T(K) . The value of activation energy and frequency factor A is to be calculated for the given reaction. Also the value of k for the given temperature is to be calculated.

Concept introduction: A certain threshold energy which is necessary for the reaction to occur is called activation energy.

The relationship between the rate constant and activation energy is given by the Arrhenius equation,

k=AeEaRT

To determine: The value of frequency factor A .

(c)

Interpretation Introduction

Interpretation: The reaction between (CH3)3CBr and OH is given. The reaction is first order with respect to (CH3)3CBr and zero order with respect to OH . The values of slope and y intercept is given from the plot of lnk versus 1/T(K) . The value of activation energy and frequency factor A is to be calculated for the given reaction. Also the value of k for the given temperature is to be calculated.

Concept introduction: A certain threshold energy which is necessary for the reaction to occur is called activation energy.

The relationship between the rate constant and activation energy is given by the Arrhenius equation,

k=AeEaRT

To determine: The value of k at 25°C .

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started 