Year 10 - Science
Distillation: fractional distillation
Separating substances
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores purification techniques, including filtration, crystallisation, and distillation. It explains formulations, uses chromatographic methods to identify pure and impure substances, and interprets chromatograms with Rf values. The emphasis is on accurate measurements.
Lesson Summary
You will learn to explain how fractional distillation works and how it differs from simple distillation in separating mixtures of fluids.
Key Notes
- 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.
Vocabulary To Learn
- 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 Mistakes To Avoid
- Pupils sometimes think that heating a substance strongly and for extended periods will improve the quality of separation via distillation.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key 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.
2. Define this scientific word and use it in context. 'fraction'
A fraction is a component of a mixture that has been separated by fractional distillation. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils sometimes think that heating a substance strongly and for extended periods will improve the quality of separation via distillation. Correction: 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.
More Lessons In This Unit
- Chromatography: paper Study Guide
- Chromatography: separating a mixture of inks Study Guide
- Comparing types of chromatography: including gas chromatography Study Guide
- Crystallisation Study Guide
- Distillation: separating a mixture of inks Study Guide
- Distillation: simple distillation Study Guide
- Filtration Study Guide
- Interpreting chromatograms Study Guide
- Potable water Study Guide
- Potable water: including sedimentation Study Guide
- Separating mixtures Study Guide
- Separating mixtures (including formulations) Study Guide
- Solutions Study Guide
- Wastewater treatment Study Guide
- Water sample analysis: dissolved solids Study Guide
- Water sample analysis: distillation Study Guide
- Water sample analysis: pH Study Guide
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