Page 2 - 3. LESSON NOTE-(COMBINATION & DECOMPOSITION REACTION)
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•  Photo decomposition reaction.
               Thermal decomposition reaction A thermal decomposition reaction can be defined as a
               decomposition reaction which is activated by thermal energy. The reaction is generally
               endothermic as energy is required to break chemical bond in order to separate the constituent
               elements.

               a. Decomposition reactions which require heat – thermolytic decomposition or thermolysis.





















                   When heated Calcium Carbonate, decomposes into Calcium Oxide and Carbon Dioxide. This
                   process is employed in the manufacturing of quick lime which is an important component in
                   industries.

                   ➢  CaCO3 → CaO + CO2
































               On heating, ferrous sulphate crystals lose water and anhydrous ferrous
               sulphate (FeSO4) is formed. So their colour changes from light green to white. On further
               heating, anhydrous ferrous sulphate decomposes to form ferric oxide (Fe2O3), sulphur
               dioxide (SO2) and sulphur trioxide (SO3).




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