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Rates of reaction - (CCEA)Effect of concentration - higher tier

The rate of reaction increases when reactant particles successfully collide more frequently. Temperature, reactant concentration, size of solid reactant particles (surface area) and catalysts can all affect the reaction rate.

Part of Combined ScienceFurther chemical reactions, rates and equilibrium, calculations and organic chemistry

Effect of concentration - higher tier

The rate of a chemical reaction can be changed by altering the concentration of a reactant in solution. If the concentration is increased:

  • there are more reactant particles
  • there are more successful collision per unit time
  • the rate of reaction increases
Effect on concentration graph

Compared to a reaction with a reactant at a low concentration (if a solution), the graph line for the same reaction but at a higher concentration:

  • has a steeper gradient at the start
  • becomes horizontal sooner

This shows that the rate of reaction was greater at the higher concentration.