fractional distillation, crude oil and its uses

what is crude oil comprised of?

its a mix of compounds (the majority of which are hydrocarbons and alkanes)

what can change the composition of a specific batch of crude oil?

where it had been extracted

how is crude oil formed?

• marine orrganisms (mainly plankton) died millions of years ago

• they were buried by sediment

• over millions of years, they were compressed under high temperatures and pressures to form crude oil

why is crude oil valuable?

it is a finite resource - there is a limited amount to be used before it is depleted

what is the purpose of fractional distillation?

to separate hydrocarbons into the sizes of its different molecules

why is it useful to split hydrocarbons into their different sizes?

as different sizes have different uses

how does fractional distillation work?

• crude oil is heated and vaporised

• the fractionating column is hottest at the bottom and coolest at the top

• as the gases rise up the tower, they condense back into a liquid

• fractions have different boiling points so will condense at different levels in the column

• bigger molecules have stronger intermolecular forces and so have higher boiling points so will exit at the bottom of the tower

• smaller molecules have weaker intermolecular forces and so have lower boiling points so will exit at the top of the tower

what is the order of products of fractional distillation (from smaller hydrocarbons to larger)?

• fuel gas

• petrol/gasoline

• naptha

• paraffin/kerosine

• diesel fuel

• fuel and lubricating oil

• bitumen

what is fuel gas used for?

bottled camping gas

what is petrol/gasoline used for?

fuel for cars, motorcycles and other smaller vehicles

what is naptha used for?

making chemicals - solvents, cleaning fluid, paint etc

what is paraffin/kerosene used for?

fuel for greenhouse heaters and jet engines

what is diesel fuel used for?

fuel for lorries, trains and other larger vehicles

what are fuel and lubricating oil used for?

heating for large buildings, fuel for ships, lubrication

what is bitumen used for?

roofing and material for road surfaces