Plaster of paris
Calcium Sulphate (Plaster of Paris), CaSO4·½ H2O
It is a hemihydrate of calcium sulphate. It is obtained when gypsum, CaSO4·2H2O, is heated to 393 K.
2CaSO4 .2H2O(s) →2CaSO4 .H2O+ 3H2O
Above 393 K, no water of crystallisation is left and anhydrous calcium sulphate, CaSO4 is formed. This is known as ‘dead burnt plaster’.
It has a remarkable property of setting with water. On mixing with an adequate quantity of water it forms a plastic mass that gets into a hard solid in 5 to 15 minutes.
The largest use of Plaster of Paris is in the building industry as well as plasters. It is used for immobilising the affected part of organ where there is a bone fracture or sprain. It is also employed in dentistry, in ornamental work and for making casts of statues and busts.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2026 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.