10.2 Catalysts

Question 1

What is a catalyst?

Answer 1

A substance that changes the rate of reaction without any permanent change itself

Question 2

What features do catalysts have?

Answer 2

Catalysts are not used up in a reaction

Catalysts can react with the reactant to form an intermediate or provide a surface for the reaction to take place

Catalyst is regenerated at the end of the reaction

Question 3

How does a catalyst increase the rate of reaction?

Answer 3

Provides an alternate reaction pathway of lower activation energy

Question 4

What is a homogenous catalyst?

Answer 4

A catalyst in the same physical state as the reactants

Question 5

What happens when a homogenous catalyst is used?

Answer 5

The catalyst reacts with the reactant to form an intermediate

The intermediate then breaks down to give the product and regenerate the catalyst

Question 6

Give two examples of a homogenous catalyst being used

Answer 6

Making esters with sulphuric acid as a catalyst (all liquids)

Ozone depletion with Cl radical (all gases)

Question 7

What is a heterogenous catalyst?

Answer 7

A catalyst with a different physical state to the reactant

Question 8

What happens when a heterogenous catalyst is used?

Answer 8

Reactant molecules are absorbed (weakly bonded) to the surface of the catalyst

Later the product molecules leave the surface of the catalyst

via desorption

Question 9

What is the advantage of using catalysts?

Answer 9

Less energy so less electricity or fossil fuel is needed