Reaction Kinetics

Question 1

When is a collision effective?

Answer 1

1) The reactants possess at least the activation energy
2) The particles collide with the correct orientation

Question 2

Define activation energy

Answer 2

The minimum amount of energy required by particles for a reaction to occur

Question 3

How does a catalyst increase the rate of reaction?

Answer 3

A catalyst decreases the amount of activation energy needed for molecules to react (provides an alternate reaction route). When activation energy is lower more molecules are allowed to react and the frequency of effective collisions increases

Question 4

What are the two types of catalysts?

Answer 4

1) Homogeneous
2) Heterogeneous

Question 5

What is a homogeneous catalyst?

Answer 5

It is a catalyst which is in the same physical state as the reactants

Question 6

What is a heterogeneous catalyst?

Answer 6

It is a catalyst that is in a different physical state of the reactants

Question 7

Describe the mode of action of a heterogeneous catalyst

Answer 7

1) Adsorption: the reactants attach to the active sites of the catalyst using some of the electrons in the molecule
2) Bond weakening: The bonds in the molecule are weakened as electrons are used to attach to catalyst
3) Desorption: Electrons are rearranged and new bonds are formed between reactants. The products leave the surface of the catalyst

Question 8

Mode of action of homogeneous catalyst

Answer 8

A homogeneous catalysts react with the reactants in one step and it is regenerated in another step of the reaction

Question 9

Why is the reaction between S208 2- and I- slow?

Answer 9

Since both particles are negatively charged

Question 10

Define order of reaction

Answer 10

The order of reaction is the power to which a concentration is raised in the rate equation