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57
Rate of Reaction
Factors Affecting the Rate of Reaction
• The rate of reaction is the fastest at the start of the reaction. As the reaction
progresses, the rate slows down and finally becomes zero when all the reactants
have been used up.
Factors affecting the rate of reaction:
• Temperature
• Pressure (for gases only)
• Concentration
• Particle Size
• Catalysts
(i) Temperature
• By increasing the temperature, the rate of reaction increases, and vice versa.
This is because, when the temperature increases:
• The Kinetic Energy of the particles increases.
• The number of successful collisions between particles increases.
• More particles have energy greater than the activation energy.
(ii) Pressure (for gases only)
• By increasing the pressure the rate of reaction increases, and vice versa. This is
because, when the pressure increases:
• The particles become tightly packed together and the separation between
them decreases.
• The frequency of collisions increases.
(iii) Concentration