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Methane Ethane Propane
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Hexane OctaneThe simplest combination of carbon and hydrogen consists of a
single carbon atom bonded to four hydrogen atoms. This molecule is
called methane. It is a gas that is combustible (burnable) in the pres-
ence of oxygen. In fact, it is so-called natural gas, obtained from fossil
fuel deposits in the earth and shipped into our homes by pipeline to
be burned in stoves and furnaces. The combination of two carbons
and six hydrogens is called ethane; it is also a combustible gas. Three
carbons and eight hydrogens make up propane, also a combustible gas
that easily liquefies under pressure and thus can be more easily stored
and transported in tanks. Four carbon atoms and ten hydrogen atoms
form butane, an even more easily liquefied combustible gas. Five car-
bons make pentane and six carbons make hexane, both combustible
liquids. Seven carbons make heptane and eight carbons make octane,
also both combustible liquids. As the number of carbons grows larger,
the liquids develop an oily consistency and get progressively thicker.
When the number of carbon atoms reaches twenty or more, the re-
sulting substance is a waxy solid.
These molecules are fossils—molecular remnants originating with
living organisms millions of years, or hundreds of millions of years,
ago. Geological processes have transformed the once living material