How is plaster of Paris prepared Why is temperature control necessary during its preparation How does it react with water?

What is plaster of Paris How is it prepared what is the action of heat on it?

Plaster of Paris is calcium sulphate hemihydrate. Preparation: (i) From gypsum (CaSO4. 2H2O): When gypsum is heated to about 393 – 403 K, partial dehydration takes place with the formation of Plaster of Paris. … (iii) The action of heat: When plaster of Paris is heated at 473 K, it forms anhydrous calcium sulphate.

How is plaster of Paris prepared Class 11?

Plaster of Paris is manufactured by heating gypsum at 423K or 150o C/300o F. On heating gypsum at 423 K, it loses water molecules and becomes calcium sulphate hemihydrate. This product is known as the plaster of Paris.

What is plaster of Paris how it is prepared give its important uses?

This is prepared by heating gypsum to 120–130°C. Uses of plaster of Paris: (i) It is used in making chalks and fire proof materials. (ii) Used for making patient plasters used in surgery and for plastering fractured parts of the body.

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What special precautions should be taken during the preparation of plaster of Paris?

Precautions:

  • Cold water should be made available to wash off the plaster.
  • Protect the eyes by wearing goggles.
  • Cover the face and hands using dust masks and gloves.
  • Casting of faces and body parts should be avoided.
  • Wet plaster must be handled properly.

Why is the temperature maintained around 393 K during the preparation of plaster of Paris?

because if gypsum is heated beyond the temperature 373 K then all the water of crystallization is removed from it which results in anhydrous calcium sulphate which is also called as dead burnt plaster. The disadvantage of this dead burnt plaster is that it doesn’t set like plaster of Paris after adding in water.

How is plaster of Paris prepared write two properties and two uses?

plaster of paris is prepared by heating gypsum (CaSO4. 2H2O) at 120°C in rotary kilns, where it gets partially dehydrated. The temperature should be kept below 140°C otherwise further dehydration will take place and the setting property of the plaster will be partially reduced.

Why during the preparation of plaster of Paris temperature is maintained at hundred degree Celsius?

Reason (R): The temperature is maintained 1000C to prevent the formation of dead burnt plaster.

How does Plaster of Paris Harden?

Answer: Plaster of Paris hardens by combining with water. Explanation: Plaster of Paris is a salt of calcium metal which is also called as calcium sulfate hemihydrate.

How is plaster of Paris Class 10?

Plaster of Paris is prepared by heating gypsum to a temperature of 373K. When gypsum is heated to a temperature of 373k ,It loses three-Fourths of its water of crystallisation and forms Plaster of Paris.

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