Question

why making statue out of plster of parisis chemical change

Answer 1

Gypsum is a crystalline mineral of hydrated calcium sulphate (chemical formula CaSO4. 2H2O). ... A mixture of gypsum and water can be poured; the gypsum hardens as the water evaporates. In art gypsum is mainly used in the partly dehydrated form of plaster of Paris (2CaSO4).

Is making statues with a plaster of Paris a chemical change? Why?

I am assuming that you are adding water to the PoP, and not just pressing the material into the mould.

Of course it is a chemical change.

CaSO4.1/2H2O changes to CaSO4.2H2O