- Coal - Wikipedia
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 | Uses, Types, Pollution, Facts | Britannica
Coal is defined as having more than 50 percent by weight (or 70 percent by volume) carbonaceous matter produced by the compaction and hardening of altered plant remains—namely, peat deposits
- What are the types of coal? | U. S. Geological Survey - USGS. gov
When peat is placed under high pressure and heat, it undergoes physical and chemical changes (coalification) to become coal There are four major types (or “ranks”) of coal
- Coal - National Geographic Society
Coal is a black or brownish-black sedimentary rock that can be burned for fuel and used to generate electricity It is composed mostly of carbon and hydrocarbons, which contain energy that can be released through combustion (burning)
- Coal explained - U. S. Energy Information Administration (EIA)
Coal is a combustible black or brownish-black sedimentary rock with a high amount of carbon and hydrocarbons Coal is classified as a nonrenewable energy source because it takes millions of years to form Coal contains the energy stored by plants that lived hundreds of millions of years ago in swampy forests
- WSGS - What is Coal
Coals are categorized by rank depending on the degree of transformation they have experienced The four coal ranks are lignite, subbituminous, bituminous, and anthracite These different coals can be identified by their color, heat content, and shininess
- What are the different types of coal?
Types, or “ranks,” of coal are determined by carbon content There are four types of coal, ordered from highest to lowest rank below Anthracite, or “hard coal,” contains the highest amount of carbon out of all coal ranks (86%-97%) 1 It has a brittle texture and lustrous sheen
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