ry to find out why is calcium sulphatehemihydrate called ‘Plaster of Paris’

The term "Plaster of Paris" is used to refer to calcium sulphate hemihydrate due to its historical association with the city of Paris. Here are the steps to understand why it is called "Plaster of Paris":

1. Historical Context: The name "Plaster of Paris" originated in the 18th century when large deposits of calcium sulphate hemihydrate were discovered near Paris, France. These deposits were extensively mined and used for various purposes, including the production of plaster.

2. Manufacturing Process: To produce Plaster of Paris, calcium sulphate hemihydrate is obtained by heating gypsum (calcium sulphate dihydrate) at a specific temperature. This process results in the removal of water molecules, leaving behind the hemihydrate form.

3. Setting Properties: Plaster of Paris has unique setting properties that make it ideal for various applications. When mixed with water, it forms a paste that can be easily molded into different shapes. The paste then hardens rapidly, forming a solid structure.

4. Versatile Uses: Plaster of Paris has been widely used in construction, art, and medicine. In construction, it is used for creating decorative elements, molds, and repairing walls. In art, it is used for sculpting, casting, and creating intricate designs. In medicine, it is used for making casts and splints to immobilize broken bones.

5. Popularity and Recognition: The extensive use of Plaster of Paris in Paris and its popularity in various fields led to the name "Plaster of Paris" being associated with calcium sulphate hemihydrate. Over time, the name became widely recognized and is still commonly used today.

In conclusion, calcium sulphate hemihydrate is called "Plaster of Paris" due to its historical association with the city of Paris, its unique setting properties, versatile uses, and its popularity in various fields.