Page 7 - Curriculum Visions Dynamic Book

What is so special about carbon?
Carbon is very special because it can form so many compounds. The explanation lies deep inside the atom. Carbon atoms can form strong links with four other atoms. This dramatically increases the number of patterns that carbon atoms can make.
Carbon can also link together in long chains or rings, carbon to carbon to carbon to carbon and so on. Chemists call these links chemical bonds; very long chains, made by joining short ones, are called polymers. And, quite unusually, these long chains cannot be destroyed by water or air or be attacked by bacteria. This explains why so many plastics do not disintegrate in the environment in the way that other materials do. Only sunlight can destroy some polymers, causing the chains to break, and the material to become brittle.
combustion: the special case of oxidisation of a substance where a considerable amount of heat and usually light are given out. Combustion is often referred to as “burning”.
compound: a chemical consisting of two or more elements chemically bonded together. Calcium atoms can combine with carbon atoms and oxygen atoms to make calcium carbonate, a compound of all three atoms.
plastic (material): a carbon-based material consisting of long chains (polymers) of simple molecules. The word plastic is commonly restricted to synthetic polymers.
plastic (property): a material is plastic
if it can be made to change shape easily. Plastic materials will remain in the new shape. (Compare with elastic, a property where a material goes back to its original shape.)
 Butane gas is a hydrocarbon and contains carbon and hydrogen bonded together. When set alight it burns, producing heat.
 Living organisms depend on carbon atoms for their existence. Tissues and bones or shells and wings are all carbon-based compounds.
 This is a piece of anthracite, a form of hard coal with a very high carbon content. Anthracite was formed by the slow decomposition of plant tissue
under high temperature and pressure, deep within the Earth.
The Carboniferous Period is a part of geological time that began
about 400 million years ago and lasted for some 60 millions years. In the
19th century geologists working in Britain recognised that much of the coal they were mining was formed during the same part of the Earth’s history.
Because coal is a carbon-based compound, they called the entire period the Carboniferous.
In fact, the Carboniferous Period contains carbon-based rocks of two kinds. During the early part, many thick beds of limestone were laid down. These Carboniferous limestones are made of calcium
carbonate and so are carbon-based rocks. They also contain large amounts of oil and natural gas (petroleum).
During the later part of the Carboniferous Period, the main coal-bearing rocks on Earth were formed, together with more
oil and natural gas (petroleum).
Geologists now know that coal and petroleum deposits
have formed in a great many geological periods, and are still forming today.
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