Fractions
Applied Science: BTEC Level 3 National Extended Diploma, topic 3.6.1
Crude Oil
Crude oil is a non-renewable (finite) resource.
Fossilised plankton
- Crude oil is made from the fossilised remnants of ancient plankton.
Found in rocks
- Crude oil is found in rocks and is used to produce fuels and other important chemicals.
Mixture of compounds
- Crude oil is a mixture of lots of different compounds that are not chemically combined.
- Most of the compounds in crude oil are hydrocarbons.
Most compounds are hydrocarbons
- Hydrocarbons are molecules made up of only hydrogen and carbon atoms.
- Hydrocarbons differ in their size, which can change the properties of the hydrocarbon.
Uses of Different Fractions of Crude oil
Fractional distillation separates crude oil into simpler, more useful mixtures. Here are the different fractions and their uses.
Gases - domestic heating and cooking
Kerosene - fuel for aircraft
Petrol - fuel for cars
Diesel oil - fuel for some cars and trains
Fuel oil - fuel for large ships and power stations
Bitumen - surfacing roads and roofs
Naphtha - making chemicals
Lubricating oil - lubricants, waxes and polishes
Properties of Hydrocarbons
A hydrocarbon's size affects its properties. A hydrocarbon's properties can affect how useful it is as a fuel.
Boiling point
- Hydrocarbons with longer chains have higher boiling points.
Viscosity
- Hydrocarbons with longer chains have higher viscosity (i.e. they are thicker and flow less easily).
Flammability
- Hydrocarbons with longer chains are less flammable.
Toxicity
- Hydrocarbons are toxic to ingest and inhale, causing serious injury or death.
Explosive
Test yourself on Fractions
Where is crude oil found?
Crude oil is...
Why is crude oil classified as a mixture rather than a compound?
Which of the fractions of crude oil is used as fuel for aircraft?
Which of the following crude oil fractions is heaviest?