CHEMISTRY

Filtration

• What is the principle?

• How does it work?

• Give one example.

• State one application.

Principle
Difference in particle size.

✅ How it works

• The mixture is poured through filter paper.

• Insoluble solid remains on the filter paper (residue).

• Liquid passes through (filtrate).

✅ Example
Sand + Water

✅ Applications

• Purifying drinking water

• Separating tea leaves from tea

Distillation

• What is the principle?

• How does it work?

• Give one example.

• State one application.

Principle
Difference in boiling points.

✅ How it works

1. Heat the mixture.

2. Lower boiling liquid evaporates first.

3. Vapour enters the condenser.

4. Condenses into pure liquid.

✅ Example
Salt water → Pure water

✅ Applications

• Desalination

• Preparing distilled water

• Separating alcohol from water

Keywords: Boiling point • Condensation • Condenser

Sublimation

• What is the principle?

• How does it work?

• Give one example.

• Name two other sublimable substances.

Principle
Some solids change directly into vapour on heating.

✅ How it works

• Heat the mixture.

• Sublimable solid changes into vapour.

• Vapour cools and forms solid crystals.

• Non-sublimable substance remains behind.

✅ Example
Ammonium chloride + Sand

✅ Other substances

• Camphor

• Iodine

• Naphthalene

Keywords: Solid → Vapour → Solid

Chromatography

• What is the principle?

• Why do substances move at different speeds?

• Give one example.

• Give two applications.

Principle
Difference in affinity for the stationary phase (paper) and the mobile phase (solvent).

✅ How it works

• Solvent rises through the paper.

• Components move at different speeds.

• Separate coloured spots appear.

✅ Example
Separating colours in black ink.

✅ Applications

• Food colouring

• Forensic science

• Drug testing

• Plant pigments

Keywords: Affinity • Solvent • Paper • Different speeds

Centrifugation

• What is the principle?

• How does it work?

• Give one example.

• State one application.

Principle
Difference in density.

✅ How it works

• Spin the mixture rapidly.

• Denser particles move outward and settle.

• Lighter particles remain above.

✅ Example
Cream from milk

✅ Applications

• Blood testing

• Dairy industry

• Laboratories

Keywords: Density • Spinning • Heavy particles settle

Crystallisation

• What is the principle?

• How does it work?

• Why is it better than evaporation?

• Give one example.

Principle
Difference in solubility with temperature.

✅ How it works

1. Prepare a hot saturated solution.

2. Filter impurities.

3. Cool slowly.

4. Pure crystals form.

✅ Better than evaporation because

• Produces purer crystals.

• Soluble impurities remain in the mother liquor.

• Gives large, well-shaped crystals.

✅ Example
Copper sulphate crystals

Keywords: Solubility • Cooling • Pure crystals

Explain the different types of separations.

Method	Principle	Example
Filtration	Particle size	Sand + Water
Distillation	Boiling point	Salt water
Sublimation	Ability to sublime	Ammonium chloride + Sand
Chromatography	Affinity for solvent & paper	Ink colours
Centrifugation	Density	Cream from milk
Crystallisation	Solubility changes with temperature	Copper sulphate