Fractional distillation Flashcards
Why do we use fractional distillation ?
To separate the hydrocarbons in crude oil, so we can use crude oil as a fuel for our cars.
What is crude oil ?
Crude oil is a fossil fuel.
How is crude oil formed ?
It is formed from the remains of plants and animals, mainly plankton, that died millions of years ago and were buried in mud. Over millions of years, with high temperatures and pressure , the remains turn to crude oil.
How can you get crude oil out of the earth ?
It can be drilled up from the rocks where it is found.
What are examples of non-renewable fuels ?!
Fossils fuels like coal, oil and gas.
How are coal, oil and gas non-renewable fuels ?
As they take so long to make that they’re being used up much faster than they’re being formed. They are finite resources and one day they will run out.
Why is fractional distillation used ?
To serparte hydrocarbon fractions.
How does fractional distillation work ?
1) The oil is heated until most of it has turned into gas. The gases renter a fractional column ( and the liquid bit is drained off)
- In the column there’s a temperature gradient ( it’s hit at the bottom and gets colder as you go up)
- The longer hydrocarbons have high boiling points. They condense back into liquids and drain out the column early in, when they’re near the bottom. The shorter hydrocarbons have a lower boiling points. They condense and drain out much later on, near the top if the column where it’s cooler.
4) You end up with the crude oil mixture separated out into different fractions. Each fraction contains a mixture of hydrocarbons that all contain a similar number of carbon atoms, so have similar boiling points.
