The chemical equation for the combustion of coal is C + O2 = CO2. In this equation, C represents the carbon in the coal, which reacts with air, represented by O2, to form carbon dioxide, or CO2.
When coal combustion occurs in an environment low on oxygen, the equation C + CO2 = 2CO may result. During this reaction, carbon and carbon dioxide react to form carbon monoxide. The combustion of coal causes the a release of heat in an exothermic reaction. Such reactions occur between a fuel source, such as carbon in coal or methane in natural gas, and an oxidizing agent, such as oxygen.