Distillation: fractional distillation
I can explain how fractional distillation works and how it differs from simple distillation in separating mixtures of fluids.
Distillation: fractional distillation
I can explain how fractional distillation works and how it differs from simple distillation in separating mixtures of fluids.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Fractional distillation is an extension of simple distillation, and is mostly used to separate mixtures of liquids.
- A main distinction between fractional and simple distillation is that the former uses a fractionating column.
- Fractional distillation has multiple real-world examples, including the fractional distillation of air.
- Fractional distillation produces fractions; these can be pure or mixtures of chemicals with very similar boiling points.
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.
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
Content guidance
- Depiction or discussion of sensitive content
- Risk assessment required - equipment
Supervision
Adult supervision required
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).
Lesson video
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Starter quiz
6 Questions
at a fixed temperature.
over a range of temperatures.
of one element or compound only.
of more than one element and/or compound.
not be separated.
be separated.
Exit quiz
6 Questions
separate two miscible liquids with very different boiling points.
to separate multiple miscible fluids with a range of boiling points.
to create a temperature gradient to separate fluids into fractions.
pure substances, or mixtures with similar boiling points.
miscible fluid mixture is heated and starts to boil forming a vapour
the vapour passes up the fractionating column, heating the bottom
most substances cool as they rise up the column and drip back down
lower boiling point substances pass as gases into the condenser
these gases are cooled in the condenser back into the liquid state
the condensed liquid is collected as the distillate fraction