(a)
Carbon atoms form the spine of
molecules. In the 1st molecule diagram on the left, all the carbon atoms are joined by
covalent carbon-carbon bonds and because of this bonding feature they are described as
hydrocarbons and collectively known as the
series.
(b)
Other hydrocarbons have carbon carbon
covalent bonds and because of this feature they are described as
, and are known as the
series of hydrocarbons illustrated by the 2nd example on the left.
(c) A simple laboratory test for an unsaturated hydrocarbon is to use
. The yellow-brown colour of the
testing reagent becomes
as the bromine reacts with the unsaturated alkenes. There is
with the alkanes.
(d) These unsaturated hydrocarbons from cracking are reactive and so are useful for making many other substances including
. These consist of large molecules, and are formed when many
molecules, of substances called
, join together.
(e) This process is called
. When unsaturated monomers join together to form a polymer with no other
being produced in the reaction, the process is called
polymerisation.
(f) Polymers are often commonly called
and are made by polymerisation. For example,
, often called polythene is made by polymerising the simplest alkene,
. Another plastic called poly(propene) is made from
.