PETROLEUM

Petroleum – the oil and gas in the earth crust – is the immense importance to humans. Petroleum occurs widely in the sedimentary rocks of the earth's crust. It may as gas, liquid, semisolid or solid, although mixtures of gas and liquids are most common.

Petroleum is a complex mixture of hydro carbon compounds with minor amounts of nitrogen, oxygen and sulfur as impurities. Forms of petroleum include crude oil. Natural gas consisting of the compound methane, butane and propane. Asphalt is obtained as a residue from certain petroleum. Commercially, crude oil is the most important form of petroleum and natural gas is second.

Petroleum is enormously important from an economic, technological and social standpoint. Fuels that derived from petroleum supply more than half of the world's total supply of energy. Gasoline, kerosene and diesel oil provide fuel for automobiles, tractors, trucks, aircraft and ships. Fuel oil and natural gas are used to heat homes and commercial buildings.

Petroleum products are used in the manufacture of synthetic fibers for clothing and in plastics, paints, fertilizers, insecticides, soaps and synthetic rubber. The uses of petroleum as a source of raw material in manufacturing have progressively increased in importance.