6. Thermodynamics and Kinetics

Within the following pairs, pick which reaction you would expect to be faster based on having a higher value of the frequency factor (A).

(b)

For the following acid–base pairs, (vi) draw a reaction coordinate diagram.

(e)

Parts (a)–(f) of this assessment refer to the rotation around the single bond of ethane.

(c) Write the rate law for this reaction.

All things being equal, would you expect a first-order reaction to be faster or slower than a second-order reaction?

Parts (a)–(f) of this assessment refer to the rotation around the single bond of ethane.

(b) What is the order of the reaction with regard to ethane?

When a small piece of platinum is added to a mixture of ethene and hydrogen, the ­following reaction occurs: Ethene

Doubling the concentration of hydrogen has no effect on the reaction rate. Doubling the concentration of ethene also has no effect.

a. What is the kinetic order of this reaction with respect to ethene? With respect to hydrogen? What is the overall order?

The reaction of tert-butyl chloride with methanol

is found to follow the rate equation

rate = k_r[(CH₃)₃C—Cl]

a. What is the kinetic order with respect to tert-butyl chloride?

Chapter 5 taught us that chemical reactions are random collisions. Experimentally, how can we make molecules collide more often?

The reaction of tert-butyl chloride with methanol

is found to follow the rate equation

rate = k_r[(CH₃)₃C—Cl]

c. What is the kinetic order overall

Under certain conditions, the bromination of cyclohexene follows an unusual rate law:

a. What is the kinetic order with respect to cyclohexene?

The molecule A undergoes a three-step reaction to make B, where the first step is rate determining. Conversely, C can be produced by A in a two-step reaction where the second step is rate determining. Show a reaction coordinate diagram for each reaction, making it clear that the reaction to make C is faster than the reaction to make B.

Under certain conditions, the bromination of cyclohexene follows an unusual rate law:

b. What is the kinetic order with respect to bromine?

How will the rate of the reaction between bromomethane and hydroxide ion be affected if the following changes in concentration are made?

b. The concentration of the alkyl halide is cut in half and the concentration of the nucleophile is not changed.