What are the combustion products of alkanes?

The combustion products of alkanes are carbon dioxide (CO2) and water (H2O).

Alkanes are a type of hydrocarbon, which are compounds made up of hydrogen and carbon atoms. When alkanes undergo combustion, they react with oxygen in the air to produce carbon dioxide and water. This is a type of exothermic reaction, meaning it releases energy in the form of heat and light.

The general equation for the complete combustion of an alkane is: CnH2n+2 + (1.5n+0.5)O2 → nCO2 + (n+1)H2O. This equation shows that for every one mole of alkane, you need 1.5n+0.5 moles of oxygen to produce n moles of carbon dioxide and n+1 moles of water.

For example, the combustion of methane (CH4), the simplest alkane, is: CH4 + 2O2 → CO2 + 2H2O. This shows that one molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water.

However, if there is not enough oxygen present, the alkane undergoes incomplete combustion. This produces carbon monoxide (CO), or even just carbon (C), as well as water. Carbon monoxide is a poisonous gas, and carbon particles can contribute to air pollution, so complete combustion is much more desirable.

In summary, the combustion of alkanes, which are hydrocarbons, results in the production of carbon dioxide and water. This reaction is exothermic, releasing energy in the form of heat and light. If there is insufficient oxygen, incomplete combustion can occur, leading to the production of carbon monoxide or carbon, both of which have negative environmental and health impacts.