Rates of reaction: effect of adding catalysts

Question 1

what is the activation energy for a chemical reaction and give and example?

Answer 1

the minimum amount of energy needed to break the reactant bonds and get a chemical reaction started e.g. lighting a bunsen burner

Question 2

describe the properties of catalysts

Answer 2

-catalysts increase the rate of a reaction but is unchanged at the end of the reaction
-the mass, colour and all other features of catalysts will remain the same at the end of the reaction
-they are specific to particular reactants
-only small amounts of catalysts are needed (which is useful as many of them are expensive and contain rare elements)
-for solid catalysts, it’s important they have a large surface area to increase their ability to catalyse a reaction faster

Question 3

explain how catalysts work

Answer 3

if a catalyst is used:
-an alternative reaction pathway is provided which lowers the activation energy of the reaction
-this means a greater proportion of colliding particles have the activation energy or more to get the reaction started
-the frequency of successful collisions increases, which increase the rate of reaction

Question 4

what energy profile diagram can be used to represent catalysts in a reaction?

Answer 4

exothermic energy profile diagram