Question

Why controlled heating of gypsum is essential to prepare plaster?

Answer 1

Answer:

Temperature should be controlled very carefully. while preparing plaster of paris from gypsum heat must be controlled. because, it should not be allowed to rise above 152 degree celsius or 425 kelvins, if the whole water is lost then anhydrous calcium sulphate is produced,whichis called dead burnt plaster

Answer 2

Gypsum(CaSO4.2H2O) is heated at 100*c or 373 k to form plaster of paris (CaSO4.1/2H2O)

this temp. should be maintained so that it evaporate 1.5 H2O moleculeor

if the temperature is increased then it will form (CaSO4) known as dead burnt plaster