Fractional distillation

Fractions

Made up of lots of different sized hydrocarbons. A mixture of hydrocarbons that are similar in size is called a fraction.

Liquid thickness

Viscosity

Set answer for fractional distillation

Crude oil is heated and vaporises.

They enter the fractional distillation column, which is hot at the bottom and cool at the top.

Different fractions condense at different temperatures because they have different boiling points.

The shorter the hydrocarbons, the higher they condense in the column, as they have lower boiling points they vaporise at higher temperatures.

Column order

Gas

Petrol

Naptha

Kerosene

Diesel

Lubricating oil

Fuel oil

Residue

Boiling points relation to chain length

Larger chain alkanes have higher boiling points due to a larger surface area