Lecture 3

Question 1

Describe the potential energy diagram for an exothermic reaction.

Answer 1

The beginning stage is higher, the hump, and then the final stage is lower

Question 2

Describe where delta Hr is located on a potential energy graph.

Answer 2

it lies underneath either the first plateau or the final plateau

Question 3

Describe the relationships of delta Hr, Ef, and Er for a exothermic reaction.

Answer 3

deltaHr< 0
Ef<Er
deltaHr ~= Ef- Er

Question 4

Describe the potential energy diagram for a thermoneutral reaction.

Answer 4

The first and second plateau are equal and lie along the x axis

Question 5

Describe the relationships of delta Hr, Ef, and Er for a thermoneutral reaction.

Answer 5

deltaHr ~= 0
Ef~=Er

Question 6

Describe the potential energy diagram for a endothermic reaction.

Answer 6

The first plateau is lower than the second one

Question 7

Describe the relationships of delta Hr, Ef, and Er for a endothermic reaction.

Answer 7

deltaHr> 0
Ef>Er
delta Hr ~= Ef -Er

Question 8

What does {#} represent?

Answer 8

It represents the transition structure. It is higher in energy than the reactants or products

Question 9

How do you get a transition structure?

Answer 9

You break a pi-bond leaving only a sigma bond. The molecules then rotate about the single bond

Question 10

When does the pi bond reform in a transition structure?

Answer 10

When the chlorine atoms are on opposite ends of the molecules