A combustion reaction is an exothermic chemical reaction between a fuel source and an oxidant. The most common fuels are hydrocarbons, which are mostly made from a mixture of hydrogen and carbon atoms, while the most common oxidantÂ is simply oxygen from air.
Hydrocarbon combustion typically results in three common products: heat, water and carbon dioxide. It is possible for the heat to generate flames in the right conditions depending on the reactants. If there is insufficient oxygen to react with the fuel, a similar reaction called incomplete combustion will occur. Incomplete combustion produces heat, water and carbon monoxide, which can be a lethal substance to humans and animals.