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CHEMISTRY

Conc Sulphuric Acid as a Dehydrating Agent
Oxygen Preparation & Thermal Decomposition
Red Cabbage Extract
Test for Water
Liquid Density Lower than Water
Reaction of Magnesium Ribbon
Universal Indicator Experiment
Metal Reactivity Experiment
Formation of Plastic Sulphur
Testing the Acidity of Carbon Dioxide
Reaction of Copper with Nitric Acid

Experiments to Test for the Presence of Water

First Test for Water
Anhydrous cobalt chloride paper is blue.It can be obtained by warming light pink hydrated cobalt chloride paper in a test tube with a gentle flame. (As seen in the picture on the left)
CoCl2.2H2O
CoCl2 + 2H2O
Blue cobalt paper will turn pink when the blue paper is wetted.

Second Test for Water
Use white anhydrous copper sulphate which will turn blue when it is hydrated with 5 molecules of water per formula unit. Kindly refer to Mr Peter Lim's coloured QA book for more details.

Third Test for Water
When solid ammonium carbonate is heated, it thermally decomposes to 2 gases and a vapour. They are ammonia gas, carbon dioxide gas and water vapour.
(NH4)2CO3(s) 2NH3(g) + CO2 + H2O(g)

Can you remember the 3 tests shown, of each test for the products? Hints: Use colourless phenolphthalein, limewater and blue anhydrous cobalt chloride paper.

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