These pages tend to build on each other and it would be best to read them in this order.
The effect of surface area on reaction rates . . .
A commonly used experiment to investigate this, and an explanation of why surface area affects the rates of reactions involving a solid and a liquid or gas.
The effect of concentration on reaction rates . . .
Another commonly used experiment to investigate this, and an explanation of why concentration matters.
The effect of temperature on reaction rates . . .
An explanation of why temperature affects rates of reaction. I am using the same experiment to demonstrate this as in the concentration page. It would be helpful if you read that page first.
The effect of pressure on reaction rates . . .
The effect of increasing the pressure on reactions involving gases.
The effect of catalysts on reaction rates . . .
Explaining why catalysts affect reaction rates. The common example of using manganese(IV) oxide in the decomposition of hydrogen peroxide.