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  • Created by: Becky
  • Created on: 19-04-13 16:01

Rates of reaction

Rate = change in concentration divided by time


  • The rate is fastest at the start of the reaction since each reactant has its greatest concentration
  • Rate slows as the reaction progresses as the concentration of the reactants decreases
  • Rate becomes zero when the reaction stops (normally when one of the reactants have been used up)

The rate of reaction can be affected by different factors 

  • Temperature - increases the amount of kinetic energy which results in more successful collisions. At higher temperatures the peak moves to the right (higher energy) with a lower height.


  • Pressure of gases - the particles are closer together so are more likely to react
  • Concentration of solutions - there are more particles that are closer together so collide more frequently
  • Catalysts - lowers the activation energy needed and so provides an alternative route.
  • Surface area - small pieces have many surfaces for reacting particles to collide with

Measuring the rate of reaction

  • Change in gas volume - volume of gas can be recorded by using a gas syringe at various times
  • Change in gas pressure - change in gas pressure can be measured by using a manometer
  • Change in mass - if a…


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