# What property allows chemists to separate gasoline from asphalt and paint thinner from jet fuel?

$\text{Differential volatility............}$
Of course when they tap an oil well, and remove its contents for processing, the crude oil is distilled at an oil refinery on a fractionating tower that may be many metres tall. The length of the tower allows efficient separation (so-called $\text{fractionation}$) of the crude petroleum into so-called distillates; i.e. they collect the fractions boiling between $40 - 60$ ""^@C, $60 - 80$ ""^@C, $90 - 110$ ""^@C, and these fractions are a mixture of alkanes and olefins; the longer the chain the more involatile the material.