Honors Chemistry 1 Chapter 17 Review Questions

Honors Chemistry 1 Chapter 17 Review Questions

Honors Chemistry 1 Chapter 17 Review Answers

What is a Reaction Mechanism? Give an example.

The step-by-step sequence of reactions by which the overall chemical change occurs

What is the slowest step in the mechanism named?

Rate Determining Step

What is an intermediate?

A substance that is made in one step of a reaction mechanism and used in another step

Where on the energy profile is the activated complex formed?

It is formed at the highest point of the curve.

What is an activated complex?

It is a transitional structure between the reactants and products.

What is the difference between the  E for and exothermic reaction and an endothermic reaction?

The  E for an exothermic reaction is negative and the  E for an endothermic reaction is positive.

What is the activation energy?

The minimum energy required to transform the reactants into an activated complex

How is the value for  E determined?

The  E is the difference between the reactants and products.

What is chemical kinetics?

The area of chemistry that is concerned with reaction rates and reaction mechanisms

What is necessary for a collision to be effective?

The collision must have sufficient energy and the correct orientation.

Draw an energy profile for an exothermic reaction and one for an endothermic reaction.

ExothermicEndothermic

What is the difference between a homogeneous reaction and a heterogeneous reaction?

A homogeneous reaction has only one phase, but a heterogeneous reaction has two phases such as solid and gas or solid and liquid.

Which is the only rate influencing factor that cannot be adjusted?

The nature of the reactants

As temperature increases; reaction rateincreases.

Tell how each of the following affects the collisions: temperature, surface area, concentration and a catalyst.

Temperature affects the frequency and energy of collisions.

Surface area and concentration affects the frequency of collisions.

A catalyst affects the efficiency of the collisions.

As surface are increases; reaction rateincreases.

As concentration increases; reaction rateincreases.

What is a catalyst?

A substance that changes the rate of a chemical reaction without itself being permanently consumed

List some ways in which a catalyst might work.

Provides an alternative energy pathway or reaction mechanism

May form an alternative activated complex that requires a lower activation energy

What is the difference between an uncatalyzed path and a catalyzed path?

The activation energy could be lower and the path would get to products faster.

Try # 6 on Page 581.

a.Eforward = +80 kJ/mol

Ereverse = -80 kJ/mol

Ea = 100 kJ/mol

Ea' = 20 kJ/mol

b. Eforward = -40 kJ/mol

Ereverse = +40 kJ/mol

Ea = 20 kJ/mol

Ea′ = 60 kJ/mol

c.Eforward = +10 kJ/mol

Ereverse = -10 kJ/mol

Ea = 70 kJ/mol

Ea′ = 60 kJ/mol