Rate of reaction

The rate of a reaction is a measure of how quickly a reactant is used up, or a product is formed. Rate of reaction is affected by factors such as concentration, pressure, temperature and surface area to volume ratio of a solid reactant.

A model of colliding particles helps to explain why different factors affect rate of reaction.

Collision theory

For a chemical reaction to happen:

  • reactant particles must collide with each other
  • the particles must have enough energy for them to react

A collision that produces a reaction is called a successful collision. The activation energy is the minimum amount of energy needed for a collision to be successful. This is different for different reactions.

Two pairs of particles move towards each other

Two pairs of particles move towards each other