4.6: Understand How to Classify Reactions of Organic Compounds as Substitution, Addition and Combustion

SUBSTITUTION REACTION: Reaction where one atom is swapped with another atom

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Example: Methane reacts with Bromine under Ultraviolet Light

Methane   +   Bromine   →   Bromomethane   +   Hydrogen Bromide             CH4                 Br2                      CH3Br                            HBr

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ADDITION REACTION: Reaction in which one molecule combines with another to form a single larger molecule

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Example: Bromine will react with Ethene by Bromine molecule adding across the double bond of Ethene

Ethene   +   Bromine   →   Dibromoethane           C2H4                 Br2                      C2H4Br2

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COMBUSTION REACTION: Chemical reaction involving burning

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Example: Alkenes burn when heated in Air of Oxygen

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If there is an unlimited supply of Oxygen, combustion reaction (complete combustion) will produce Carbon Dioxide and Water:

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CH4   +   2O2   →   CO2   +   2H2O        C3H8   +   5O2   →   3CO2   +   4H2O

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If there is a limited supply of Oxygen, combustion reaction (incomplete combustion) will produce Carbon Monoxide and Water:

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CH4   +   ½ O2   →   CO   +   2H2O