Factors Affecting Rate of Reaction

The rate of a chemical reaction can be increased or decreased by changing the conditions. Understanding the factors that affect the rate of reaction is central to the AQA GCSE Chemistry specification and links closely with collision theory, which you will study in the next lesson. This lesson covers each factor in detail, including concentration, temperature, surface area, pressure and catalysts.

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Overview of Factors

There are five main factors that affect the rate of a chemical reaction:

Factor	Effect on Rate When Increased
Concentration of reactants in solution	Increases the rate
Temperature	Increases the rate
Surface area of solid reactants	Increases the rate
Pressure of gaseous reactants	Increases the rate
Catalyst (adding one)	Increases the rate

Each of these factors works by changing the frequency or energy of collisions between reacting particles. The details of why are explained by collision theory (see next lesson), but this lesson focuses on what each factor does and how it is investigated.