The rate of chemical reaction is defined as the change in the concentration of any one of the reactants or products per unit time to complete the reaction.

Any four factors which affect the rate of chemical reaction are:

1. Temperature: Increasing the temperature generally speeds up a reaction because particles move faster, leading to more frequent and energetic collisions between them.
2. Concentration: Higher concentrations of reactants result in more particles in a given volume, which increases the chances of collisions and thus speeds up the reaction.
3. Surface Area: For solid reactants, increasing the surface area (e.g., by grinding into a powder) allows more particles to be exposed and available for reaction, leading to a faster rate.
4. Catalysts: Catalysts are substances that speed up a chemical reaction without being consumed in the process. They lower the activation energy required for the reaction, increasing the rate.