Understanding Rate of Reaction

  1. Rate of reaction is defined as the change in the amount of reactants or products per unit time.
  2. It is a measure of how fast a reaction occurs.
    1. Fast Reaction = Rate of reaction is high.
    2. Slow Reaction = Rate of reaction is low
  3. A fast reaction taken shorter time for the reaction to complete.

Example of fast reaction
Type of Reaction Example
Combustion Combustion of magnesium in oxygen
Mg+ O 2 MgO Combustion of ethane (C2H6) C 2 H 6 + 7 2 O 2 2C O 2 +3 H 2 O
Reaction between reactive metal and water Reaction between potassium and water 2K+2 H 2 O2KOH+ H 2
Reaction between metal carbonate and acid Reaction between limestone/ marble and sulphuric acid CaC O 3 + H 2 S O 4 CaS O 4 +C O 2 + H 2 O
Ionic precipitation (Double decomposition) Precipitation of silver(I) chloride AgNO 3 + HClAgCl +  HNO 3

Example of slow reaction
Type of Reaction Example
Photosynthesis 6CO 2 +  6 H 2 O C 6 H 12 O 6 +  6O 2
Rusting 4Fe+3O 2 +  2H 2 O 2Fe 2 O 3 H 2 O
Fermentation C 6 H 12 O 6 2C 2 H 5 OH +  2CO 2