Form 1:
Classification of substances

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Suspension/ precipitates/solid-liquid mixture which do not dissolve

Experiment: To make soil, flour and Lead (II) Iodide suspension/precipitate Procedure

Put about 100 cm3 of water in three separate beakers. Separately place a half spatula end full of soil, maize and lead (II) Iodide to each beaker. Stir for about two minutes.

Observation

Some soil, maize and lead (II) Iodide float on the water

A brown suspension/precipitate/particles suspended in water containing soil

A white suspension/precipitate/particles suspended in water containing flour

A yellow suspension/precipitate/particles suspended in water containing Lead (II) iodide. Some soil, maize and lead (II) Iodide settle at the bottom after some time.

Explanation

Some solid substances do not dissolve in a liquid. They are said to be insoluble in the solvent .When an insoluble solid is put in liquid:

(i) Some particles remain suspended/floating in the liquid to form a suspension /precipitate.

(ii) Some particles sink/settle to the bottom to form sediments after being allowed to stand.

An insoluble solid acquire the colour of the suspension/precipitate .e.g.

1. A white suspension /precipitate have some fine white particles suspended /floating in the liquid. Not white solution

2. A blue suspension /precipitate has some fine blue particles suspended /floating in the liquid.

3. A green suspension /precipitate has some fine green particles suspended /floating in the liquid.

4. A brown suspension /precipitate has some fine brown particles suspended /floating in the liquid.

5. A yellow suspension /precipitate has some fine yellow particles suspended /floating in the liquid.

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