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Chemical Changes (RI TONG) - Coggle Diagram
Chemical Changes (RI TONG)
Decomposition by Electrolysis
When electricity is passed through acidified water, it decomposes into hydrogen gas and oxygen gas
Water → oxygen + hydrogen
Sodium chloride can be decomposed into its elements by electrolysing molten sodium chloride
Sodium chloride → sodium + chlorine
Example
Household bleach is produced by the electrolysis of concentrated sodium chloride
Aluminium is extracted from its ore using electrolysis
Aluminium oxide → Aluminium + oxygen
Thermal Decomposition
When a carbonate is strongly heated, an oxide and carbon dioxide are formed
Copper carbonate → copper oxide + carbon dioxide
Calcium carbonate → Calcium oxide + carbon dioxide
Sugar → Carbon + Water Vapour
When carbon dioxide is bubbled through calcium hydroxide, white precipitate is formed
Oxidation
Respiration
In the cells of living things this occurs to produce energy to do work.
Sugar + oxygen → Carbon dioxide + water
Rusting
Iron + water + oxygen → Iron hydroxide (rust)
Combustion
Oxidation of substances to produce heat and light
Carbon + oxygen → carbon dioxide
Methane + oxygen → carbon dioxide + water
Petrol + oxygen → Carbon dioxide + water
Magnesium + oxygen → magnesium oxide