Fractional Distillation Worksheet

Fractional distillation can be used to separate a mixture of compounds with different boiling points such as crude oil or air.

Air is a mixture of nitrogen, oxygen, carbon dioxide and some other gases. The composition of air is shown in the pie chart below.

Pie chart of gases of the air

To separate this mixture the air must be cooled to -200 ^oC, which turns it into a liquid. It is then warmed up slowly and each of the liquids boil off at a different temperature and can be collected and removed.

Distillation of liquid air

Fractional distillation can also be used to separate crude oil into the many compounds that it is made up of. This is very important as crude oil contains some very useful compounds such as petrol and diesel. The products of fractional distillation are shown in the diagram below:

Fractional distillation of crude oil

Use this activity to find out more about this method of separating mixtures of liquids.

Which of the following is the process used to produce petrol from crude oil?

filtration

fractional distillation

evaporation

Which gas is the main component of air?

nitrogen

oxygen

carbon dioxide

Distillation of air can be used to separate the gases in air. The air must first be turned into a liquid. What temperature is air cooled to before distillation takes place?

-2°C

-20°C

-200°C

Match each of the substances to the raw material that they can be produced from.

Column A	Column B
aviation fuel	crude oil
petrol	crude oil
oxygen	air
nitrogen	air
lubricating oil	crude oil
plastics	crude oil

Which of the products from fractional distillation is not used as a fuel?

natural gas

petrol

residue

List the fractions produced from crude oil in order of increasing boiling points.

	Highest Boiling Point	Lowest Boiling point
Residue
Natural Gas

ANSWERS

Question 1

Which of the following is the process used to produce petrol from crude oil?

CORRECT ANSWER

fractional distillation

EDDIE SAYS

Fractional distillation separates crude oil into fractions that can be used to produce many products.

ANSWERS

Question 2

Which gas is the main component of air?

CORRECT ANSWER

nitrogen

EDDIE SAYS

The air we breathe contains about 80% nitrogen gas.

ANSWERS

Question 3

Distillation of air can be used to separate the gases in air. The air must first be turned into a liquid. What temperature is air cooled to before distillation takes place?

CORRECT ANSWER

-200°C

EDDIE SAYS

The air is cooled to -200°C before being slowed warmed and the different components collected as they turn into a gas. That's because at -200°C all the various components of air are liquids, all mixed together, since that temperature is lower than their boiling points.

ANSWERS

Question 4

Which of the following is produced from the distillation of crude oil? Tick three boxes.

CORRECT ANSWER

petrol
gas
diesel oil

EDDIE SAYS

The distillation of crude oil can be used to produce many products.

ANSWERS

Question 5

Which of the following is produced from the distillation of air? Tick two boxes.

CORRECT ANSWER

oxygen
nitrogen

EDDIE SAYS

Air is made of mostly nitrogen and oxygen and so these gases are produced when the air is separated.

ANSWERS

Question 6

Match each of the substances to the raw material that they can be produced from.

CORRECT ANSWER

Column A	Column B
aviation fuel	crude oil
petrol	crude oil
oxygen	air
nitrogen	air
lubricating oil	crude oil
plastics	crude oil

EDDIE SAYS

Crude oil is used to produce lots of products but the distillation of air is used to produced nitrogen and oxygen only.

ANSWERS

Question 7

Which of the products from fractional distillation is not used as a fuel?

CORRECT ANSWER

residue

EDDIE SAYS

The residue fraction is combined with small stones to create tar for our roads and pavements. Most of the fractions produced from crude oil are burned as fuels.