New
New
Year 10
Edexcel
Foundation

# Distillation: fractional distillation

I can explain how fractional distillation works and how it differs from simple distillation in separating mixtures of fluids.

New
New
Year 10
Edexcel
Foundation

# Distillation: fractional distillation

I can explain how fractional distillation works and how it differs from simple distillation in separating mixtures of fluids.

Share activities with pupils
Share function coming soon...

## Lesson details

### Key learning points

1. Fractional distillation is an extension of simple distillation, and is mostly used to separate mixtures of liquids.
2. A main distinction between fractional and simple distillation is that the former uses a fractionating column.
3. Fractional distillation has multiple real-world examples, including the fractional distillation of air.
4. Fractional distillation produces fractions; these can be pure or mixtures of chemicals with very similar boiling points.

### Common misconception

Students sometimes think that heating a substance strongly and for extended periods will improve the quality of separation via distillation.

Stress that distillation is a skill which requires careful control of heating so only one substance is in the condenser at a time. Understanding the link between application of heat to the mixture, boiling point and reading a thermometer is essential

### Keywords

• Fraction - A fraction is a component of a mixture that has been separated by fractional distillation.

• Fractional distillation - Fractional distillation is a method used to separate miscible fluids (liquids or gases) with different boiling points into individual components (fractions).

• Miscible - Fluids that dissolve in another fluid are described as miscible in that fluid.

• Boiling point - The temperature at which a substance changes between a liquid state and a gas state is known as its boiling point.

• Fractionating column - A fractionating column is a piece of apparatus within which a temperature gradient develops. It is used during fractional distillation.

Have 'simple' and fractional distillation set ups and compare / contrast them. Use fractional distillation to separate ethanol from water then compare the flammability of the distillate and the starting mixture.
Teacher tip

### Content guidance

• Contains subject matter which individuals may find upsetting.
• Equipment requiring safe usage.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
A mixture is a substance which is made up from more than one element and/or compound which are ...
chemically bonded together.
Correct answer: not chemically bonded together.
always have the same boiling point.
always in the same state.
Q2.
is the process by which a gas is cooled into a liquid.
Q3.
Air is an example of ...
an element.
a compound.
Correct answer: a mixture.
Q4.
Match the following statements to make complete sentences about pure substances and mixtures.
Correct Answer:A pure substance boils ...,at a fixed temperature.

at a fixed temperature.

Correct Answer:A mixture boils ...,over a range of temperatures.

over a range of temperatures.

Correct Answer:A pure substance consists ...,of one element or compound only.

of one element or compound only.

Correct Answer:A mixture consists ...,of more than one element and/or compound.

of more than one element and/or compound.

Correct Answer:A pure substance can ...,not be separated.

not be separated.

Correct Answer:A mixture can ...,be separated.

be separated.

Q5.
Simple distillation can be used to separate solutions. Order the following processes that occur during simple distillation.
1 - Heat the mixture.
2 - The component with lowest boiling point boils.
3 - Vapour is cooled.
4 - Vapour condenses.
5 - Distillate is collected.
Q6.
In the diagram below, give the letters in order for where forces between the particles are overcome or where they are being reformed.
c and b
b and c
Correct answer: a and b
c and a
b and a

## Exit quiz

### 6 Questions

Q1.
What are miscible fluids?
liquid and solid substances that can mix
Correct answer: liquids and/or gases which can dissolve in each other
any liquids that are mixed together
Q2.
are produced by fractional distillation. They may be pure, i.e. contain one component, or a mixture containing multiple components with similar boiling points.
Q3.
What is the purpose of fractional distillation?
to mix multiple fluids together with different boiling points
Correct answer: to separate multiple fluids with different boiling points
to produce a single fraction
to produce a single pure fluid
Q4.
Match the following statements to make complete sentences related to distillation:
Correct Answer:Simple distillation can be used to ... ,separate two miscible liquids with very different boiling points.

separate two miscible liquids with very different boiling points.

Correct Answer:Fractional distillation can be used ...,to separate multiple miscible fluids with a range of boiling points.

to separate multiple miscible fluids with a range of boiling points.

Correct Answer:A fractionating column can be used ...,to create a temperature gradient to separate fluids into fractions.

to create a temperature gradient to separate fluids into fractions.

Correct Answer:Fractions are ...,pure substances, or mixtures with similar boiling points.

pure substances, or mixtures with similar boiling points.

Q5.
A mixture of liquid fractions; X (b.p. 40 - 100°C), Y (b.p. 120 - 160°C) and Z (b.p. 180 - 200°C) was heated quickly to 150°C. What would be found in the distillate?
X, Y and Z
X only
Correct answer: X and Y
Y
Q6.
Match the letter with the correct statement concerning the steps occurring during fractional distillation.
Correct Answer:a,miscible fluid mixture is heated and starts to boil forming a vapour

miscible fluid mixture is heated and starts to boil forming a vapour

Correct Answer:b,the vapour passes up the fractionating column, heating the bottom

the vapour passes up the fractionating column, heating the bottom

Correct Answer:c,most substances cool as they rise up the column and drip back down

most substances cool as they rise up the column and drip back down

Correct Answer:d,lower boiling point substances pass as gases into the condenser

lower boiling point substances pass as gases into the condenser

Correct Answer:e,these gases are cooled in the condenser back into the liquid state

these gases are cooled in the condenser back into the liquid state

Correct Answer:f,the condensed liquid is collected as the distillate fraction

the condensed liquid is collected as the distillate fraction