Crude oil is a mixture of lots of different hydrocarbons. Hydrocarbons are compounds which only contain hydrogen and carbon.
Some of these hydrocarbons are very small such as methane (CH4). This has a very low boiling point and is very flammable. As the hydrocarbons get bigger in size their boiling point increases and they become less flammable.
- Crude oil is heated to 350°C
- Most of the substances in the crude oil are evapourated
- It is pumped into the bottom of a factioning tower
- Heavier hydrocarbons are already liquid or condense
- Smaller hydrocarbons (low bpt.) rise up the tower
- As hydrocarbons are cooled to their bpt. , they condese
- Some hydrocarbons (low bpt.) are collected as gases
- Short chain ones are more useful as fuels
- Their general formula is CnH2n+2 (where n=no. of carbons)
- The carbon - carbon bonds in alkanes are all single covalent bonds
- This means they are saturated hydrocarbons
- only have c-c single bonds
- carbon atoms already have bonds to 4 other atoms so it's not possible to bond to new atoms