• Two methods to test the presence of water will be introduced.

1) Using dry cobalt chloride paper 2) Anhydrous copper (II) sulphate. • What is water? Water is a compound which contains 2 Hydrogen molecules, and 1 Oxygen molecule to form H2O. Water exists in three state

s – solid, liquid and gas.

Materials and Apparatus:Materials and Apparatus:

• Dry cobalt chloride paper 2 pieces • Unknown substance several • Dropper 1 dropper• Forceps 1 forceps Cobalt Chloride Paper:Cobalt Chloride Paper:

• stored in a desiccator• should be blue in colour

Procedure:Procedure:

Add a drop of unknown substance to a piece of dry cobalt chloride paper.

Possible ResultsPossible Results

1) The dry cobalt chloride paper turns from blue to pink, it proves that there is water in the unknown liquid.

2) The color of the dry blue cobalt chloride

paper remains unchanged, it shows that water is absent in the liquid.

Chemical Symbol: Anhydrous CuSO4 Anhydrous means ‘without water’. Anhydrous Copper (II) Sulphate is whit

e in color. Reaction between water and Anhydrous

Copper (II) Sulphate is reversible.

Results:Results:

Anhydrous CuSO4 is dry, when water is added, it turns from white to the familiar hydrated blue crystals. This proves that water is present.

• There are two ways to test for the presence of water. The use of dry cobalt chloride paper is relatively an easier process than using Anhydrous Copper (II) Sulphate.

• Therefore, dry cobalt chloride paper is more commonly use than Anhydrous Copper (II) Sulphate.