Carbon and some of its compounds

Since the complete story of carbon would be a history of organic chemistry, asphalt, carbonate rocks, alkaline carbonates, fuels, foods, plant and animal nutrition, photosynthesis, and respiration, the following brief sketch can merely suggest the magnitude of the subject. 

In the second decade of the eighteenth century, Dr. Rosinus Len-tilius (Linsenbahrdt) (1657-1733) discussed the occurrences of coal. The best description of coal, said he, is given by Friedr. Hoffmann (in obs. phys. chem. libr. II. obs. 24). He says that these coals are a loose, porous earth intimately penetrated by a large amount of a subterranean resinous fluid. Their principal constituent is the lesin, for when that has been lost, they no longer smoke and burn.. (4). He also described the 

Per Kalm stated, in the account of his journey to North America in 1748-51, that Coals have not yet been found in Pennsylvania, but people pretend to have seen them higher up in the country among the natives. Many people, however, agree that drey are met with in great quantity more to the north, near Cape Breton (5). 

In 1824 an anonymous contributor to the Aesculapian Register of Philadelphia wrote as follows Much as we are gratified with the vast advantages which we promise ourselves by the introduction of the Lehigh Coal into common use, we already perceive an evil arising from it, which it becomes necessary to counteract.— Unlike the fuel heretofore employed, its ashes afford no alkali that can render them useful in the formation of soap nor as yet have they probably been sufficiently tested as a manure. Our streets have therefore become their deposit. . . (7). He believed that until coal could be sold at from 20 to 25 cents a bushel, it would be unable to compete successfully with wood. 

The inhabitants of ancient Nineveh used an asphaltic mortar prepared from partially evaporated petroleum (8). In some translations of the Old Testament, this substance is called pitch or slime. When Noah built the ark, he was told to pitch it within and without with pitch. For building the Tower of Babel, Noah s descendants had brick for stone, and slime had they for mortar (9). 

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Nitration using this reagent was first investigated, by Francis. He showed that benzene and some of its homologues bromobenzene, benzonitrile, benzoyl chloride, benzaldehyde and some related compounds, and phenol were mono-nitrated in solutions of benzoyl nitrate in carbon tetrachloride anilines would not react cleanly and a series of naphthols yielded dinitro compounds. Further work on the orientation of substitution associated this reagent with higher proportions of o-substitution than that brought about by nitric acid this point is discussed below ( 5.3.4). 

The Murchison meteorite shown in Figure 6.7, like all meteorites, is named after the place from which it was recovered and in this case it is the town of Murchison, Victoria in Australia about 100 km north of Melbourne. The fall occurred in 1969 and was followed by an analysis of the chemical composition in some considerable detail. The Murchison meteorite is a carbonaceous chondrite containing about 2 per cent carbon, some as inorganic carbonates, and some as soluble compounds such as amino acids but the bulk as a macromolecular heterogeneous material referred to as kerogen. 

This alternative hybridization scheme explains how carbon can combine with four atoms in some of its compounds and with three other atoms in other compounds. You may be aware of the conventional way of depicting carbon as being tetravalent in all its compounds it is often stated that carbon always forms four bonds, but that sometimes, as in the case of ethylene, one of these may be a double bond. This concept of the multiple bond preserves the idea of tetravalent carbon while admitting the existence of molecules in which carbon is clearly combined with fewer than four other atoms. 

Let us begin our study of stereochemistry with methane and some of its simple substitution products. Any compound however complicated, that contains carbon bonded to four other atoms can be considered to be a derivative of methane and whatever we learn about the shape of the methane molecule can be applied to the shapes of vastly more complicated molecules. 

Liquid-Gas Soiutions Carbonated beverages are liquid-gas solutions—carbon dioxide is the gaseous solute, and water is the liquid solvent. The carbon dioxide gas gives the beverage its fizz and some of its tartness. The beverage also might contain other solutes, such as the compounds that give it its flavor and color. 

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