what happens when copper sulphate crystals are heated?
Copper sulphate is a hydrated salt which contains 5 molecules of water of crytsallisation, and so is denoted by the chemical formula CuSO4.5H2O. These 5 molecules of water of crytsallisation are responsible for the blue colour of the salt. However, when copper sulphate is heated for some time, the blue colour disappears and it becomes white-gray in colour. This is because the water molecules are lost on heating and copper sulphate pentahydrate is converted to anhydrous copper sulphate.
Copper sulphate contains 5 molecules of water of crystallisation and its chemical formula is CuSO4.5H2O. It is blue in colour and when heated, it loses the 5 molecules of water of crystallisation and forms anhydrous copper sulphate which is grey-white in colour. Thus, this is a physical change and not a chemical change since copper sulphate is only losing water molecules on heating. Moreover, no new chemical substance is being formed in the process, hence it is not a chemical change but a physical change.
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