Crude Oil and Hydrocarbons

Crude oil is found in rocks. It’s a finite resource, meaning that one day it will run out.

Crude oil is formed over millions of years from the remains of plankton which were buried in mud.

Crude oil is a mixtures of molecules called hydrocarbons, which means molecules made up of only hydrogen and carbon atoms.

ALKANES

Alkanes is the name for specific types of hydrocarbons found in crude oil. The key feature of alkanes is that they have this general formula:

CnH(2n+2)

This means that, if we know the number of carbon atoms in the alkane (n), then we can calculate the number of hydrogen atoms by multiplying the number of carbon atoms by 2, then adding 2.

E.g.

Methane is an alkane with one carbon atom. To work out the hydrogen atoms, we multiply 1 by 2 then add 2, which gives us 4.

This means methane has one carbon atom bonded to 4 hydrogen atoms.

Ethane is another alkane with 2 carbon atoms. To work out the hydrogen atoms, we multiply 2 by 2 then add 2, which gives us 6.

This means ethane has 2 carbon atoms bonded to 6 hydrogen atoms.

Key alkanes:

• Methane

• Ethane

• Propane

• Butane

Alkanes are saturated molecules, meaning that the carbon atoms are fully bonded to hydrogen atoms.