A chemical that is found in a material in very small amounts, but can change the material's properties.

A single element or compound that is not mixed with any other substance.

A smaller portion of a larger quantity of a substance.

A separation technique that uses boiling and condensation to remove and isolate a liquid component of a mixture.

The liquid that is condensed from the gas state during distillation.

Water sample analysis: distillation

Combined science

Separating mixtures (including formulations)

Solutions

Filtration

Crystallisation

Chromatography: paper

Interpreting chromatograms

Chromatography: separating a mixture of inks

Distillation: simple distillation

Distillation: separating a mixture of inks

Distillation: fractional distillation

Potable water

Wastewater treatment

Water sample analysis: pH

Water sample analysis: dissolved solids

In the Making Salts unit, pupils will build on their understanding of separation techniques to learn about the process of making salts and writing balanced chemical equations.

In the Separation Techniques unit, pupils learned about various methods for separating mixtures, including filtration, evaporation, distillation, and chromatography.

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.

Separating substances

What process would produce pure water from potable water containing dissolved solids?

What does a boiling point range of 98°C to 102°C suggest about the water sample?

What is indicated by a boiling point of 100°C?

To cool and condense the vapour back into a liquid

What is the purpose of the condenser in the distillation apparatus?

To ensure the distillate evaporates again

Why is it important to collect the distillate in a clean container?

Compare the boiling points before and after distillation

How can you determine the effectiveness of distillation from boiling point data?

What is the main principle behind the separation of mixtures in distillation?

Soluble substances pass through the filter

Why can't filtration separate soluble substances from liquids?

What does a change in the boiling point of a liquid indicate?

Water sample analysis: distillation

Lesson outcome