The chemical process in which a substance reacts with oxygen to give heat and light is called combustion. Combustion is an exothermic chemical reaction that releases heat and light. The most common type of combustion is the burning of fossil fuels, such as gasoline, diesel, and coal. When these fuels are burned, they react with oxygen to produce carbon dioxide and water vapor. The heat and light released by this reaction can be used to power engines, heat homes, and generate electricity.