Question

define the state of coal.
​

Answer 1

There are four types of coal:

1) Anthracite: It is the best kind of coal. It is hard, brittle and lustrous. It has high percentage of carbon and very small amount of moisture.

2) Bituminous: Bituminous coal is a soft, dense, black coal. Bituminous coal often has bands of bright and dull material in it. Bituminous usually has a high heating value.

3) Lignite: Lignite is brownish black, has a high moisture content (up to 45 %), and a high sulphur content. It is a low grade with very less amounts of carbon.

4) Peat: Decaying plants in swamps produce peat, which has low carbon content and high moisture content. It is widely used as a domestic fuel.

Answer 2

Answer:

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen.[1] Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years.