Combustion

Just a quick reply to an issue which was raised in a previous post surrounding 'incomplete combustion'.

Complete combustion

In complete combustion, the burning fuel will produce only water and carbon dioxide (no smoke or other products). The flame is typically blue. For this to happen, there needs to be enough oxygen to combine completely with the fuel gas.

Many of us use methane gas (CH₄), commonly known as natural gas, at home for cooking. When the gas is heated (by a flame or spark) and if there is enough oxygen in the atmosphere, the molecules will break apart and reform totally as water and carbon dioxide.

Incomplete combustion

If there is not enough oxygen available during a chemical reaction, incomplete combustion occurs, and products such as carbon (C) and carbon monoxide (CO) as well as water and carbon dioxide are produced. Less heat energy is released during incomplete combustion than complete combustion. In incomplete combustion, the burning flame is typically yellow or orange and there is smoke.

Hope this answers your query!

Jack Scott

http://www.sciencelearn.org.nz/Contexts/Fire/Science-Ideas-and-Concepts/What-is-fire