Page 38 - Curriculum Visions Dynamic Book

Combustion of fuels
When a material burns it undergoes a chemical reaction (combustion) that produces new products and gives out heat. Some materials give out more heat than others. Those that give out the most heat for the smallest volume are called fuels.
The products of fuel combustion are usually carbon dioxide and water vapour, together with any compounds of nitrogen and sulphur that might have been in the fuel as impurities. Solid particles of carbon and carbon monoxide gas may also be produced if the combustion was not complete.
The volume and mass of the products are greater than the volume and mass of the fuel. This is because oxygen is taken from the air.
For example, when one hundred grams of propane fuel is burned it releases three hundred grams
of carbon dioxide. This is because the product contains two hundred grams of invisible oxygen taken from the air.
The temperatures at which combustion occurs vary widely. For example, kerosene (aviation fuel) burns at about 300°C, wood and petrol at 350°C, coal at 400°C, hydrogen (rocket fuel) at about 600°C and aluminium at 2000°C.
  These pictures show that charcoal will simply glow in air, even when heated strongly by a Bunsen burner. However, when the hot charcoal is placed in a
gas jar containing oxygen, the charcoal combusts and a ball of white-hot carbon is produced. Carbon dioxide is given off until the oxygen is used up.
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