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Grade 9 Intermediate About 15 min Version 1 Awaiting review Premium

Sorting substances by their physical properties

A physical property can be observed or measured without changing what the substance is: its colour, state, whether it dissolves, its melting point, or whether it conducts electricity. Solids that dissolve in water are soluble; those that do not are insoluble. Liquids that mix completely with water are miscible; those that form a separate layer are immiscible. These properties help chemists identify substances and choose how to separate mixtures.

What you will learn

  • Carry out simple tests of physical properties.
  • Distinguish soluble from insoluble solids and miscible from immiscible liquids.
  • Use properties to choose a method of separation.

Before you start

  • Know the meaning of dissolve, solution and mixture.

Materials

  • Salt, sugar, copper sulfate, chalk, sand, iron filings, candle wax, ethanol, vinegar, kerosene, cooking oil, glycerine

Equipment

  • Test tubes, water, spirit lamp, conductivity tester, spatula

Procedure

  1. Choose a card and add the substance to water: does it dissolve, mix or form a layer?
  2. Heat a small sample and test whether its solution conducts electricity.
  3. Place each card in the right group.