Carbon

Carbon

Carbon! It is a non-metal which is solid at room temperature. It exists naturally as diamond and graphite. It also exists in pure form as diamond and graphite. It can also exists as an impure substance as coal, coke, charcoal, bicarbonate, metallic carbide etc. The chemistry of carbon is known as the organic chemistry.

Carbon exhibits a phenomenon known as allotropy ( is the existence of two or more different forms of an element with the same physical state ). Diamond and graphite are the crystalline allotropes of carbon, while coal, coke, charcoal, lamp black, are amorphous or non crystalline allotropes of carbon.

Crystalline Carbon

Diamond

Diamond is one of the allotropes of carbon. Diamond is a colourless transparent solid that is octahedral in shape. It is the hardest known substance hence, nothing can cut diamond. Note, we use diamond to cut diamond. It is a non conductor of electricity due to the existence of covalent bond in its structure, leading to no free mobile electrons in the diamond crystal.
Diamond is used in drilling because of its hardness. It is mainly used in making jewelleries because it shines continually when polished and it has a very high refractive index.
Diamonds are naturally deposited in Africa, Brazil, India and Siberia. The world's main supply of diamonds comes from southwestern Africa.

Graphite

Graphite is a black opaque solid and hexagonal in structure. It is very soft. Unlike diamond, graphite is a good conductor of electricity because only three out of four valence electrons involved in bond formation, the extra electron is responsible for the conduction of electricity.
Graphite is less dense than diamond. It is an excellent lubricant. It is used as electrode in electroplating and in dry cells, due to its good conduction of electricity. A mixture of graphite and clay is used as lead in pencil. It can withstand high temperature. It is also used in atomic bomb as a neutron moderator.  Graphite can be produced in large quantity by heating coke in an electric furnace  to a very high temperature for about 20-30 hours. This process is called the ACHESON PROCESS.

Amorphous Carbon

Coal

Coal is formed by plant decay in the absence of air. Whereby,carbon(IV)oxide ,methane and water are liberated during the decomposition, leaving behind the coal. Various types of coal include peat, lignite, bituminous, and anthracite. Coal is used to generate power from steam engine. Impurities present in coal are nitrogen, sulphur and phosphorous.

Coke

Coke is formed by heating bituminous coal in the absence of air to drive away all volatile constituent. This is called destructive distillation of coal.

Bituminous coal   ---------> coke + ammonical liquor + coal tar + coal gas

Coke is the  only non volatile form. Ammonical liquor is a solution of ammonia in water, when mixed with an acid it is used as a fertilizer. Coal gas is a mixture of carbon (IV) oxide, hydrogen, and methane. Coal tar is a mixture of different organic solvents.
Coke is used as a powerful reducing agent. It is used in manufacture of graphite in Acheson process. It is also used as fuel. It is the major constituent of gaseous fuel such as water gas.

Wood

Wood is also a complex substance like coal. The amount of water in wood is higher than that of coal, but the percentage of carbon in coal is higher than that in wood. The destructive distillation of wood is shown below,
Wood --------> Wood charcoal + Pyroligneous acid + Wood tar + Wood gas

Charcoal

Charcoal is formed by heating wood, sugar, animal refuse, bone even blood in a limited supply of air. Wood charcoal is the commonest charcoal and contains sulphur impurities. It is used in absorbing poisonous gas and for the purification of noble gases. Sugar charcoal is the purest form of charcoal while animal charcoal has the highest percentage of impurities.

Soot

Soot are finely divided carbon  particles also known as carbon black. They are used in manufacturing black shoe polish, carbon paper, rubber type, typewriter ribbon etc. Free Gift.