8.1 rate of reaction

Rate =

Change in amount of reactants or products / time

Define activation energy

The minimum energy that colliding particles must possess for a collision to be effective

Draw the reaction pathway for an exothermic reaction

Draw the reaction pathway for an endothermic reaction

According to collision theory, a reaction will speed up if:

• the frequency of collisions increases

• The proportion of particles with energy greater than the activation energy increases

Define catalyst

A substance that speeds up the rate of reaction by providing an alternative reaction pathway and thus lowering the activation energy

How does the use of a catalyst affect the reaction pathway?

What does the collision theory state?

For a chemical reaction to take place, particles need to collide with each other in correct orientation with enough energy

How does increasing concentration affect the rate of reaction?

• causes an increased frequency of collisions

• Therefore an increased frequency of successful collisions

• Thus an increased rate of reaction

How does increasing pressure affect the rate of reaction?

• the molecules have less space in which they can move

• This means that the number of successful collisions increases due to an increased collision frequency

• An increase in pressure therefore increases the rate of reaction