vitrinite: fossil woody tissue, likely often charcoal from forest fires in the coal forests
fusinite: made from peat made from cortical tissue
exinite: fossil spore casings and plant cuticles
resinite: fossil resin and wax
alginite: fossil algal material
Carbon forms more than 50 percent by weight and more than 70 percent by volume of coal (this includes inherent moisture). This is dependent on coal rank, with higher rank coals containing less hydrogen, oxygen and nitrogen, until 95% purity of carbon is achieved at Anthracite rank and above. Graphite formed from coal is the end-product of the thermal and diagenetic conversion of plant matter (50% by volume of water) into pure carbon.
Coal usually contains a considerable amount of incidental moisture, which is the water trapped within the coal in between the coal particles. Coals are usually mined wet and may be stored wet to prevent spontaneous combustion, so the carbon content of coal is quoted as both a 'as mined' and on a 'moisture free' basis.
Lignite and other low-rank coals still contain a considerable amount of water and other volatile components trapped within the particles of the coal, known as its macerals. This is present either within the coal particles, or as hydrogen and oxygen atoms within the molecules. This is because coal is converted from carbohydrate material such as cellulose, into carbon, which is an incremental process (see below). Therefore coal carbon contents also depend heavily on the degree to which this cellulose component is preserved in the coal.
Other constituents of coals include mineral matter, usually as silicate minerals such as clays, illite, kaolinite and so forth, as well as carbonate minerals like siderite, calcite and aragonite. Iron sulfide minerals such as pyrite are common constituents of coals. Sulfate minerals are also found, as is some form of salt, trace amounts of metals, notably iron, uranium, cadmium, and (rarely) gold.
Methane gas is another component of coal, produced from methanogenesis. Methane in coal is dangerous, as it can cause coal seam explosions, especially in underground mines, and may cause the coal to spontaneously combust. It is, however, a valuable by-product of some coal mining, serving as a significant source of natural gas.
2007-02-19 08:38:58
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answer #1
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answered by Anonymous
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Coal is formed when all the leaves wash down the river to the delta where it will deteriorate into gas,oil,and after a long time coal.
2007-02-19 17:44:02
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answer #2
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answered by JOHNNIE B 7
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Coal is made of carbon-based life forms (in other words any living thing) that has undergone centuries of extreme heat and massive pressure deep within the earth. If the coal continues in this massive heat and pressure it may eventually become diamond.
2007-02-19 16:36:56
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answer #3
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answered by Ryan HG 2
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Coal is formed by millions of years of compression underground from trees. If you examine a piece you can still see the grain of the wood.
2007-02-19 16:35:47
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answer #4
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answered by Maid Angela 7
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Carbon, which in the case of coal came from the crushed remains of dead plants.
2007-02-19 18:08:00
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answer #5
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answered by funnelweb 5
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Carbon
2007-02-19 16:34:16
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answer #6
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answered by spiegy2000 6
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It is carbon which any living thing is made up of.
2007-02-19 16:38:25
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answer #7
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answered by Rory M 2
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Compressed fossilised vegetation.
2007-02-19 16:35:02
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answer #8
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answered by Anonymous
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carbon compound
2007-02-19 16:44:11
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answer #9
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answered by briggs 5
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fossilised trees
2007-02-19 16:34:10
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answer #10
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answered by Good Egg 6
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