(a) What is plaster of Paris? Write the chemical formula of plaster of Paris.
(b) How is plaster of Paris prepared? Write the chemical equation of the reaction involved.
(c) Explain why plaster of Paris should be stored in a moisture-proof container.
(d) State two important uses of plaster of Paris.
(a) Plaster of Paris is a white colour substance that becomes hard when coming into the contact of water. It is prepared by heating gypsum. The chemical formula of plaster of Paris is CaSO4.12 H2O.
(b)CaSO4.2H2O Gypsum heat to 373K−−−−−−−→CaSO4.12H2O Plaster of Paris
(c)It has a property of setting into a hard mass when water is added into it, within half an hour. The setting of plaster of Paris is due to its hydration to form crystals of gypsum which set to form a hard and solid mass.
(d)