Page 6 - Microsoft Word - Module-4

Properties:

 White floppy powder and insoluble in water.

CaCO 1200k CaO + CO
3
2
CaCO + H SO  CaSO + H O + CO
3
2
2
2
4
4
Uses:
 Used as a building material (marble) and

manufacture of quick lime.

 Used as an antacid, constituent of chewing gum.

(d)Calcium Sulphate (plaster of paris), CaSO .1/2H O
4
2
It is a hemihydrate of CaSO and obtained when
4
gypsum is heated to 393k.

2(CaSO .2H O)  2(CaSO ). H O +3H O
4
2
4
2
2
Properties:
 Above 393k anhydrous CaSO is formed known as
4
dead burnt plaster.

 On mixing with an adequate quantity of water

plaster of paris forms a plastic mass that gets into

a hard solid in 5 to 15 minutes.