Question

Why does complete combustion release more energy than incomplete combustion?

Answer 1

Complete combustion reacts oxygen with a fuel to produce carbon dioxide and water. Because the air we breathe is only 21% oxygen, a large volume of air is required for complete combustion to take place. Combustion is an exothermic reaction that releases energy in the forms of heat and light. When a fuel undergoes complete combustion, it releases the maximum amount of energy from the fuel being reacted.

Incomplete combustion is also a reaction between oxygen and fuel but the products are carbon monoxide, water and carbon. Incomplete combustion occurs when a combustion reaction occurs without a sufficient supply of oxygen. Incomplete combustion is often undesirable because it releases less energy than complete combustion and produces carbon monoxide which is a poisonous gas. Incomplete combustion can also produce pure carbon (soot) which is messy and can build up in equipment.