What is Coal? -- Science Ncert / Cbse Revision Notes
During the carboniferous age, the earth had large amounts of plant life and dense forests in swampy and low-lying wetland areas. Plants and other life forms, after their death, drifted down to the bottom of the swamps, where they were compressed and decomposed to form peat. Coal was formed due to the compression of the peat at high temperature and pressure. As coal was formed from the remains of vegetation, it is called a fossil fuel.
Carbonisation is the slow process of conversion of dead vegetation into coal. Coal is the world’s most abundant fossil fuel. There was a time when it was used as a primary fuel for cooking and driving railway engines. It is now the largest source of fuel to generate electricity all over the world.
Coal is primarily made up of carbon, also hydrogen, oxygen, nitrogen and some amounts of sulphur.
Surface mining is used when coal is found close to the surface or hillsides. Underground mining is used to extract coal that is deep beneath the surface of the earth.
Warren Hastings, the first governor general of West Bengal, initiated the commercial coal mining at Raniganj in the year 1774. Coal is processed in the industry to get useful products coke, coal tar and coal gas. Coke from coal is black, tough and porous. It is an almost pure form of carbon that is used in the manufacture of steel and extraction of metals.
Coal tar is a black, thick mixture of almost 200 substances. It is used as a starting material for manufacturing synthetic dyes, explosives, perfumes, drugs and plastics, synthetic resins, paints and stains.
Naphthalene balls, which are used to repel moths and other insects, are also obtained from coal tar.
Bitumen, a petroleum product, is now used in place of coal tar for surfacing roads.
Coal gas is obtained during the processing of coal to get coke. It is mainly used as a fuel in industries around coal processing plants. In the year 1810, for the first time coal gas was used for street lighting in London. It was used in New York in the year 1820. Now, it is used more as a source of heat than light.
Uses of coal:
- Coal gas is obtained during the processing of coal to get coke. It is mainly used as a fuel in industries around coal processing plants.
- Coal is the largest source of fuel used to generate electricity world-wide.
- Coal is used in manufacturing industries for heat and power applications.
- Coal is used to make steam for heating.
- It is also used as coke in steel making.
Resources occurring naturally are called natural resources. These are of two types:
- Inexhaustible natural resources
- Exhaustible natural resources
Must Read : Natural Resources
Resources available in unlimited quantity and not likely to be exhausted by human activity are called inexhaustible natural resources. Examples: Sunlight and air.
Resources available in limited quantity and likely to be exhausted by human activity are called exhaustible natural resources. Examples: Forests, wildlife, minerals and coal.
- It is black in colour.
- It is solid like a rock.
- It was used in railway engines as fuel in the olden days.
- It is used in thermal power production.
- It is used in various industries.
Millions of years ago, when forests got buried, the dead plants got converted into coal due to the high pressure and temperature under the soil. This process of conversion of dead vegetation into coal is called carbonation. Coal is formed from the remains of vegetation, and hence, it is called fossil fuel. Coal is processed in the industry to get different products like coke, coal tar, coal gas, etc.
- It is a porous and black substance.
- It is a pure form of carbon.
- It is used in the extraction of steel and many other metals.
- It is a black thick liquid with an unpleasant smell.
- It is a mixture of 200 substances.
- The products obtained from coal tar are used as starting materials for manufacturing substances like dyes, drugs, explosives and perfumes.
- Coal gas is obtained during the processing of coal to coke.
- It is used as a fuel in many industries.