Sorting substances by their physical properties
Test common laboratory substances with water, heat and a conductivity tester, and group them by how they behave.
Core concept
Physical properties such as solubility, miscibility, melting and conductivity can be used to identify and group substances
Topic: Matter
A physical property can be observed or measured without changing what the substance is: its colour, state, whether it dissolve: To mix into a liquid so completely that you can no longer see the pieces. All key words, 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 mixture: Two or more substances mixed together, which can be separated again. All key words.
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
- Choose a card and add the substance to water: does it dissolve, mix or form a layer?
- Heat a small sample and test whether its solution conducts electricity.
- Place each card in the right group.