Carbon dioxide
Combustion

The combustion of all carbon-based fuels, such as methane (natural gas), petroleum distillates (gasoline, diesel, kerosene, propane), coal, wood and generic organic matter produces carbon dioxide and, except in the case of pure carbon, water. As an example, the chemical reaction between methane and oxygen:

Iron is reduced from its oxides with coke in a blast furnace, producing pig iron and carbon dioxide:
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