The branch of science that deals with the study of the composition and the physical and chemical properties of various forms of matter is called chemistry.

Fuel is any substance that can provide heat and produce energy when it is burned. This energy that releases is generally in the form of chemical energy or heat energy. The recent invention of nuclear technology means now even nuclear energy may be released due to nuclear fission or fusion.

The word "Alchemy" has its origin in a Greek word 'Khemeia' which means "art of transmuting metals". Alchemy is the persons who perform the transformation of substances mainly of all elements in to gold and silver. In the ancient times, the study of chemical science was limited to alchemists.