Crude Oil

Question 1

What is the purpose of fractional distillation? For crude oil

Answer 1

To separate hydrocarbons in crude oil so they are useful

Question 2

As the size of molecules are smaller

Answer 2

Boiling point is lower
High flammability
Low viscosity (easily flows / not thick)
Shorter chains

Question 3

As size of molecules is larger

Answer 3

Higher boiling points
High viscosity (doesn’t flow easily / thick)
Low flammability
Longer chain lengths

Question 4

Explain how fractions are obtained from crude oil by fractional distillation (4)

Answer 4

Crude oil is heated to vaporise
There is a temp gradient in the fractioning column
So the gases condense at different levels of fractioning column
Because of their different boiling points
They leave fractioning column at different trays

Question 6

What is a fraction

Answer 6

A mixture of hydrocarbons with similar length and boiling points