Amorphous forms of carbons consist of coal, charcoal and carbon black. Millions of years ago, due to geographical changes, plants were buried under the earth crust. High temperature and absence of air converted them to coal is a complex material consisting mainly of hydrocarbons and other organic compounds. It contains 60 to 90% carbon together, oxygen. Nitrogen, sulphur, aluminium and silicon when coal is heated at high temperature, it decomposes producing a variety of gases and liquid products. The mixture of gases which are largely methane, hydrogen and carbon monoxide is known as coal gas and the mixture of liquids containing hydrocarbons other organic compounds is called coal tar. The solid residue left during this process is called coke. It contains 90 to 95% carbon.
Charcoal is obtained by heating wood and other organic materials to a high temperature in the absence of air. It is porous and brittle solid. It is lighter than wood. Its density is very low. Charcoal is extremely porous and its structure resembles to sponge. It is usually crushed into very fine powder before use due to large surface area it can absorb gases as well as other impurities from a number of materials. It is used for removing pleasant and dangerous gases from air. It is also used for removing burnt hydrocarbons from automobile exhaust.
Carbon black is also the purest form of carbon. It is formed by burning some natural oil in limited supply of air. Carbon black is very soft powder. It is used for making carbon paper, inks and paints. Carbon black is added to rubber to increase its strength and stiffness. That's why the tyres are usually black in colour.
Charcoal is obtained by heating wood and other organic materials to a high temperature in the absence of air. It is porous and brittle solid. It is lighter than wood. Its density is very low. Charcoal is extremely porous and its structure resembles to sponge. It is usually crushed into very fine powder before use due to large surface area it can absorb gases as well as other impurities from a number of materials. It is used for removing pleasant and dangerous gases from air. It is also used for removing burnt hydrocarbons from automobile exhaust.
Carbon black is also the purest form of carbon. It is formed by burning some natural oil in limited supply of air. Carbon black is very soft powder. It is used for making carbon paper, inks and paints. Carbon black is added to rubber to increase its strength and stiffness. That's why the tyres are usually black in colour.