Links
Hydrocarbons
Revision Questions
gcsescience.com 8 gcsescience.com
What is an Alkane?
Alkanes are organic
molecules that form an homologous
series
with the general
formula CnH2n+2.
Homologous series
means that
the series has the
same general formula
and
the compounds have
similar properties and structure,
differing
only in the number of CH2 units
in the chain. The "chain"
is the line of
carbon atoms joined together.
Members
of
the
same series show a gradual change in physical
properties
for example the boiling point
increases as the chain gets longer.
| Methane, CH4, has n=1. | Pentane, C5H12, has n=5. |
| Ethane, C2H6, has n=2. | Hexane, C6H14, has n=6. |
| Propane, C3H8, has n=3. | Heptane, C7H16, has n=7. |
| Butane, C4H10, has n=4. | Octane, C8H18, has n=8. |
Below are links to the structure
of some alkanes.
Some of these molecules exist as isomers.
The
structural formula
is sometimes called the displayed formula.
Alkanes
are hydrocarbons
that have single bonds between
all of the atoms.
They have the maximum number of
hydrogen atoms for the number of carbon atoms present,
and so alkanes are called saturated hydrocarbons.
Links
Hydrocarbons
Revision Questions
gcsescience.com The Periodic Table Index Hydrocarbons Quiz gcsescience.com
Home GCSE Chemistry GCSE Physics
Copyright © 2015 gcsescience.com. All Rights Reserved.