Hydrocarbons from crude oil Flashcards
How is crude oil refined in a distillation plant?
1) The complex mixture of hydrocarbons in crude oil is first separated into fractions.
2) Each fraction consists of a mixture of hydrocarbons with similar boiling points.
3) Pure liquids have a fixed boiling point, a pure hydrocarbon can be obtained by further distillation of a crude oil.
What is the definition of fractional distillation?
The separation of the components in a liquid mixture into fractions which differ in boiling point(and hence chemical composition) by means of distillation,typically using a fractionating column.
How does fractional distillation work?
1) Crude oil vaporised
2) gasses pass up the column
3) Gases reach a temperature that is lower than their boiling points. Here, the vapour condenses to a liquid. The liquids are then tapped off into storage containers.
What happens to the fractions contained for the crude oil?
They can be used as fuels or may be further processed to make petrochemicals. The fractions can also be distilled further to form pure liquids in other fractionating columns.
What is the effect of chain length with the boiling points of alkanes?
As the chain length increases there are more points of contact leading to more van der Waal’s forces between molecules.
What does the effect of branching have on the boiling points of alkanes?
Branched molecules have fewer points of contact and are further apart than unbranched molecules so there are fewer intermolecular forces.
