Carbon And How It Effect Our Lives Essay, Research Paper

CARBON AND HOW IT EFFECT OUR LIVES

Although widely distributed in nature, carbon is not particularly plentiful (it makes up only about 0.025 percent of the Earth’s crust). Yet it forms more compounds than all the other elements combined. In 1961 the isotope carbon-12 was selected to replace oxygen as the standard relative to which the atomic weights of all the other elements are measured; carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radio labeling.

Elemental carbon exists in three forms, each of which has its own physical characteristics. Two of the forms, diamond and graphite, are crystalline in structure. They differ in physical properties because the arrangements of the atoms in their structures are dissimilar. The third form, known as carbon black, is amorphous in structure and includes charcoal, lampblack, coal, and coke, although X-ray examination has revealed that these substances do possess a low degree of crystallinity. Diamond and graphite can be produced synthetically; they are chemically inert but do combine with oxygen at high temperatures, just as amorphous carbon does.

Pure diamond is the hardest naturally occurring substance known and is a poor conductor of electricity. Graphite, on the other hand, is a soft, slippery solid that is a good conductor of both heat and electricity. Because of their beauty, diamonds are valued as jewels and, because of their hardness, as abrasives for cutting, grinding, and drilling. Graphite is used as a lubricant, in paint, and, mixed with clay, as the “lead” of pencils; because it conducts electricity but does not melt, graphite also is used for electrodes in electric furnaces and dry cells as well as for making crucibles in which metals are melted.

Each of the amorphous forms of carbon has its own specific character; hence, each has its own particular applications. All are products of oxidation and other forms of decomposition of organic compounds. Coal and coke, for example, are used extensively as fuels; charcoal is used as an absorptive and filtering agent and as a fuel and in the manufacture of gunpowder. In addition to its uses in making inks, carbon paper, typewriter ribbons, and paints, carbon black also is added to the rubber used in tires to improve its wearing qualities. Bone black, or animal charcoal, can adsorb gases and coloring matter from many other materials; a major use is in decolorizing raw sugar.

Carbon has two stable isotopes, carbon-12 (which makes up 98.89 percent of natural carbon) and carbon-13 (1.11 percent); five radioactive isotopes are known, of which the longest-lived is carbon-14, which has a half-life of 5,730 +/- 40 years.

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