13.6 Catalyst

Question 1

Define a catalyst

Answer 1

A catalyst is a substance that increases the rate of the reaction by lowering the activation energy without the substance being consumed

Question 2

How does a catalyst increase the rate of a reaction?

Answer 2

Catalyst increases the rate of reaction by lowering the activation energy (Ea) without itself being consumed

It speeds up a reaction by providing a set of elementary steps with more favorable kinetics than those that exist in its absence

Rate constant or rate depend upon the Ea value. The smaller the Ea, the greater the rate

Question 3

A certain rxn is known to proceed slowly at room temperature. Is it possible to make the rxn proceed at a faster rate without changing the temp?

Answer 3

Yes, it’s possible to make the reaction proceed at a faster rate without changing the temperature by using an enzyme catalyst. Enzyme catalyst increases the rate of reaction without affecting temperature

Question 4

Distinguish between homogeneous catalyst and heterogeneous catalyst.

Answer 4

In a heterogeneous catalyst, the reactants and the catalysts are in different phases usually the catalyst is a solid and the reactants are either gases or liquids
Where as a homogeneous catalyst, the reactants are dispersed in a single phase, usually liquid

Question 5

Are enzyme-catalyze reactions examples of homogeneous or heterogeneous catalysis?

Answer 5

Enzyme catalysis is usually homogenous because the substance and enzyme are present in aqueous solution