Page 7 - Microsoft Word - Module-4

Uses:

 Used as plaster in building and in bone fracture.

 Used in dentistry and for making casts of statues

and busts.

(e)Cement:

It is also called Portland cement because it resembled

the natural lime stone in the Isle of Portland in

England.

Raw Materials:

Limestone and clay (aiumino silicate)

Setting of cement: when mixed with water setting of

cement takes place to give a hard mass. Gypsum is

added to slow down the setting time of cement so that

it gets sufficiently hardened.

Uses: it is used in building industry, concrete and in

plastering.

BIOLOGICAL IMPORTANCE OF Mg AND Ca

 The main pigment for the absorption of light in

plants is chlorophyll which contains Mg.

 Ca is present in bones and teeth and plays important

roles in neuro muscular function.