Chemical Reactions

The pH scale

Combustion reactions are those in which a substance reacts with oxygen and heat is released. Burning is a combustion reaction that produces a flame. The substance that reacts with oxygen in a combustion reaction is called a fuel. The chemical word equation for the combustion of octane is: octane + oxygen → carbon dioxide + water.

Fossil fuels such as natural gas, petrol and coal have formed from the remains of living things. They are compounds of hydrogen and carbon called hydrocarbons. The products of the combustion of fossil fuels always include carbon dioxide and water. Because of impurities in fossil fuels, these are not the only products of their combustion. In some cases various dangerous gases, including carbon monoxide, are also produced.

The fuel used in jet aircraft is kerosene, which is obtained from crude oil. Like the octane in cars, the vapour of this fossil fuel reacts with oxygen. An electrical spark is used to start the reaction. The chemical word equation for the combustion of kerosene in a jet engine is: kerosene + oxygen → carbon dioxide + water.

A chemical reaction called respiration takes place in every cell of your body. Respiration is a slow combustion reaction. The energy required by your body is released when the fuel, glucose from your digested food, reacts with oxygen from the air that you breathe. The products of respiration are carbon dioxide and water. The chemical word equation for respiration is: glucose + oxygen → carbon dioxide + water.

Harry's Lab

Acids and Bases

The pH scale

Endothermic or Exothermic?

Combustion reactions

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