## Alkanes

Crude oil is mostly made up of a group of called the .

A is a series of molecules which:

• have the same
• differ by CH2 in the of neighbouring compounds
• show a gradual variation in
• have similar chemical properties

The table shows four alkanes, their molecular formula, displayed formula and ball-and-stick model diagram.

### General formula

The formula of any alkane can be worked out using the general formula CnH2n+2 where n = the number of carbon atoms.

For example, for a hydrocarbon with ten carbon atoms:

• n = 10 and 2n+2 = 22
• the formula is C10H22
Question

Work out the formula for a hydrocarbon molecule with 6 carbon atoms.

C6H14