文档介绍：pounds
——hydrocarbons
The term "organic" appears to have been used for the first time about 1777 and was applied to those materials occurring in or derived from anisms. Accordingly, such substances as starch, alcohol, and urea were classified anic, for starch is produced by living plants, alcohol is a product of fermentation caused by anisms, and urea is contained in urine. In 1824, however, the German chemist WÖhler synthesized urea, and the original meaning of the term “organic” no longer applied. pounds, in the modern sense, are pounds of carbon. Many thousands of pounds which are not found in or derived from anisms have been produced by chemists, and well over a pounds are already known.
The existence of so pounds is due primarily to the ability of carbon atoms bine with other carbon atoms, forming chains of different lengths and rings of different sizes. The elements, other than carbon, most frequently found pounds are hydrogen, oxygen, nitrogen, sulfur, the halogens, phosphorus, and some of the metals. Although the number pounds is vast, the study anic chemistry is greatly simplified by the fact that the chemistry of pounds can anized around “functional groups”, each of which imparts similarities in chemical properties.
Hydrocarbons
The pounds are those containing only carbon and hydrogen. pounds are known as hydrocarbon. Some of them are found in nature, where they were derived from plant or animal forms of life. Several types of hydrocarbons are possible.
The alkanes
The series pounds which have the general empirical H2n+2, where n is an integer, is called the alkane, or paraffin.
The lighter members of the alkane series are gases, the members of intermediate weight are liquids, and the heavier members are solids. From the formulas of pounds it is evident that each member differs from the preceding one by the increment CH2. A series pounds in which each member differs from the one before it by mon increment is called a homologous series.
The electro