There are several ways to increase the rate of a chemical reaction. In order for a chemical reaction to take place three things need to happen:
1. Reactant molecules need to collide with each other.
2. Collisions need to be with enough energy for molecules to react.
3. Molecules need to collide in the correct orientation. Increasing the rate of collisions will increase the effective collisions.
Here are some factors that make these three things happen with more frequency, increasing the rate of a reaction:
Raise the temperature. The rate of most reactions increases with temperature because particles move faster and have more collisions with more energy.
Shake, stir or agitate. This brings reactants in contact with each other more frequently.
Increase the concentration of the reactants. This increases the number of collsions between reactant particles.
Use smaller particles of solids. Grinding solids to a finer size allows them to be surrounded by more of the other reactant. For example, sawdust is more flammable than wood.