Preparation of Plaster of Paris Class 10

Today we are going to explain the preparation of Plaster of Paris Class 10 with a complete explanation. In this, you will learn how to prepare Plaster of Paris and the properties and uses of Plaster of Paris.

Preparation of Plaster of Paris 

             Table of content

1.    Plaster of Paris formula

2.    Chemical Name of Plaster of Paris

3.    Physical Properties of Plaster of Paris

4.    Preparation method of Plaster of Paris

5.   Chemical properties of Plaster of Paris

6.    Plaster  of Paris uses

7.    Difference between Gypsum and Plaster of Paris

8.    FAQs

 Preparation of Plaster of Paris Class 10

Plaster of Paris formula

`CaSO_4. frac\{1}{2}H_2O`

Chemical name of Plaster of Paris

Calcium sulphate hemi hydrate

Physical Properties of Plaster of Paris

1.  It is a white powder.

2.  On mixing water, it becomes hard in 15 to 20 minutes.

3.  It has a smooth ad fine texture.

4.  It dissolves slowly in water.

5.  It has low density.

6.  It has a porous structure when becomes hard.

 

 Preparation method of Plaster of Paris

Plaster of Paris is prepared by heating gypsums at 373K, partial dehydration takes place and Plaster of Paris is obtained.

Following is the Chemical equation for the preparation of plaster of Paris

  `2CaSO_4. 2H_2O  \overset{373K}{\rightarrow}2CaSO_4. ½ H_2O + 3 H_2O`

 Chemical properties of Plaster of Paris

i.     When water is added to Plaster of Paris, it becomes hard in 15 to 20 minutes.

 `2CaSO_4. 1/2H2O + 3H_2O \rightarrow  2CaSO_4. 2H_2O`

ii.      Plaster of Paris in non-inflammable.

Plaster of Paris uses

i.       Its most important use is in making plaster for repairing fractured bones in hospitals.

ii.      It is used in making statues and surfaces smooth.

iii.   It is used in chemistry labs for sealing the air gaps in air-tight apparatus.

iv.     It is also used in dental clinics.

v.       It is used in making buildings.

vi.   It is used in fire extinguishers.

 

Differences between gypsum and Plaster of Paris

Characteristic	Gypsum	Plaster of Paris
Occurrence	It is a natural substance	It is prepared by heating gypsum
Chemical name	Calcium sulphate dihydrate	Calcium sulphate hemihydrate
Chemical composition	`CaSO_4.2H_2O`	`CaSO_4. 1/2H_2O`
Water content	It contains more water molecules	contains fewer water molecules
Setting time	It takes a long time to settle.	It takes less time to settle.
Strength	Weaker	Stronger

 

FAQs

    1.  Name the raw material used for the preparation of the plaster of Paris?

 Ans -  Gypsum

2.  A compound which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water. Identify the compound.

Ans – Plaster of Paris

   3.  What is burnt Plaster?

   Ans – Anhydrous calcium sulphate is known as a burnt plaster.

   4.  What is the chemical name and formula of plaster of Paris and gypsum?

Ans – Plaster of Paris is calcium sulphate hemihydrate `CaSO_4. 1/2H_2O` and gypsum is calcium sulphate dihydrate `CaSO_4. 2H_2O`.

   5.  Is Plaster of Paris acidic or basic?

Ans – Plaster of Paris is neutral in nature.

   6.  Is gypsum powder the same as the Plaster of Paris?

Ans – Yes, Gypsum powder and plaster of Paris are the same but have some minor differences regarding their chemical composition and setting properties.

  7.  Which is the stronger gypsum and plaster of Paris?

Ans – Plaster of Paris is stronger than gypsum.

   8.  Why plaster of Paris is called plaster of Paris?

Ans - Plaster of Paris got its name because it was manufactured from special gypsum found in abundance near Paris. The term "Plaster of Paris" is associated with the city ‘Paris’.

   9.  Why plaster of Paris is a hemihydrate?

Ans –   One molecule of calcium sulphate is attached to half of the water molecule so it is called hemihydrate.

   10.  What are the medical uses of plaster of Paris?

Ans – Plaster of Paris is used in the medical field, especially in the treatment of fractured bones and dental cures.

11.  What are the medical uses of plaster of Paris?

Ans – Plaster of Paris is used in the medical field, especially in the treatment of fractured bones and dental cures.

12.  Is the plaster of Paris toxic?

Ans- Plaster of Paris is non-toxic but it is advisable not to intake.

13.  What helps the plaster of Paris in the setting?

Ans – The setting of Plaster of Paris is due to the process of hydration. When water is added to Plaster of Paris, the water molecules combine with calcium sulphate hemihydrate molecules and form dihydrate crystals. These dihydrate crystals interlock with each other and thus Plaster of Paris settle down.

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