Hydrocarbons

Hydrocarbons are compounds that contain only carbon and hydrogen atoms. Depending on the
kinds of bonds found between the carbon atoms (only single bonds can exist between carbon and
hydrogen), hydrocarbons can be classified into one of four classes: alkanes, alkenes, alkynes, and
aromatics.

ALKANES

Alkanes are hydrocarbons that contain only single bonds. They all have a molecular formula of the

general form CnH 2 n (^) + 2, where n is some positive integer. They are all named by attaching the suffix -
ane to a prefix that indicates the number of carbon atoms. These prefixes will be used again in the
naming of other hydrocarbons and it is therefore worth knowing at least a few. Properties of the
simplest six alkanes are shown in Table 16.1.
Table 16.1 Properties of Simple Alkanes

of C Atoms Prefix Name of Alkane Molecular Formula

1 meth- methane CH 4
2 eth- ethane C 2 H 6
3 prop- propane C 3 H 8
4 but- butane C 4 H 10
5 pent- pentane C 5 H 12
6 hex- hexane C 6 H 14

A CLOSER LOOK

Alkanes are nonpolar    and therefore   tend    to  have    low melting and boiling points  in  general.