What is combustion?
Combustion is a rapid chemical reaction of a substance with oxygen involving the production of heat and light. Combustion is an exothermic reaction accompanied by the development of heat so that temperature rises considerably.
Combustion reaction with insufficient oxygen produces carbon monoxide instead of carbon dioxide. In general combustion processes, oxidation-reduction reactions where oxidizing agent is the oxidant and the reducing agent is the fuel.
Combustion Formula is expressed by
Heat of combustion = Heat of formation of products – Heat of formation of reactants.
The easiest way to identify a combustion reaction is that the products always contain carbon dioxide and water.
- Complete Combustion is an oxidation of hydrocarbon producing only carbon dioxide and water. Example for clean combustion is burning of candle wax, where the heat from the wick vaporizes wax (a hydrocarbon), which reacts with oxygen to release carbon dioxide and water
- Incomplete Combustion is hydrocarbon oxidation that produces carbon monoxide and/or carbon (soot) in addition to carbon dioxide. Example of incomplete combustion is burning of coal, where a lot of soot and carbon monoxide is released.
Combustion of methane
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)
Burning of naphthalene
C10H8 + 12 O2 → 10 CO2 + 4 H2O
Combustion of ethane
2 C2H6 + 7 O2 → 4 CO2 + 6 H2O
Combustion of butane ( found in lighters)
2C4H10(g) +13O2(g) → 8CO2(g) +10H2O(g)
Combustion of methanol ( wood alcohol)
2CH3OH(g) + 3O2(g) → 2CO2(g) + 4H2O(g)