Combustion Reactions

Combustion Reaction The very rapid reaction of a substance with oxygen to produce compounds called oxides (often called burning) Word equation to represent combustion: fuel + oxygen  oxides + energy The energy produced is mainly in the form of heat and light and the fuel can be a variety of elements and compounds. The products of a combustion reaction are either complete or incomplete.

Complete Combustion of Hydrocarbons In a complete combustion reaction, the supply of oxygen is plentiful. The only products of complete combustion are carbon dioxide and water Word equation to represent complete combustion of a hydrocarbon hydrocarbon + oxygen  carbon dioxide + water + energy (blue flame) The most important fuels we burn are hydrocarbons (Ex: gasoline, natural gas, kerosene)

Complete Combustion of Hydrocarbon Examples hydrocarbon + oxygen  carbon dioxide + water + energy CH4 + O2  CO2 + H2O C4H10 + O2  CO2 + H2O CH3OH10 + O2  CO2 + H2O C6H12O6 + O2  CO2 + H2O C7H14 + O2  CO2 + H2O

Incomplete Combustion of Hydrocarbons In an incomplete combustion reaction, the supply of oxygen is limited. The products of complete combustion are are carbon monoxide gas, carbon (soot), carbon dioxide and water Word equation to represent incomplete combustion of a hydrocarbon hydrocarbon + oxygen  carbon dioxide + water + carbon monoxide + carbon + energy Carbon monoxide is an odourless, colourless gas that is highly toxic. Carbon monoxide is produced by a running vehicle in an enclosed space and poorly ventilated furnaces. Soot is common in older vehicles with poorly maintained engines

Incomplete Combustion of hydrocarbon Examples hydrocarbon + oxygen  carbon dioxide + water + carbon monoxide + carbon + energy (yellow flame) hydrocarbon + O2  CO2 + H2O + CO + carbon + energy CH4 + O2  H2O + CO C3H8 + O2  H2O + CO

Incomplete Combustion continued…… In some cases, metals will react with oxygen in the combustion reaction and an oxide of a metal will be produced. General word equation Element + Oxygen  Oxide + Energy For example: Mg + O2  MgO Li + O2  Li2O Na + O2  Na2O