Question

The difference of water molecules in Gypsum and Plaster of Paris (POP)?
A. $\dfrac{5}{2}$
B. $\dfrac{1}{2}$
C. 1
D. $1\dfrac{1}{2}$

Answer 1

Hint:We were asked to find the difference between water molecules in Gypsum and plaster of paris. So, we’ll discuss how gypsum and plaster of Paris is made. Then we’ll write on the reactions of those two compounds then will acknowledge the difference between the amounts of water molecules present.

Complete step by step answer:
Gypsum may be a soft sulphate mineral composed of calcium sulphate dihydrate, with the formula , on the opposite hand, plaster of Paris may be a white powdery slightly hydrated calcium sulphate made by calcining gypsum and used chiefly for casts and moulds within the sort of a quick-setting paste with water. It's manufactured as a dry powder and is mixed with water to make a stiff but workable paste immediately before it's applied to the surface. The reaction with water liberates heat through crystallization and therefore the hydrated plaster then hardens.
When gypsum is heated in air it loses water and converts first to calcium sulphate hemihydrate, (basanite, often simply called "plaster") and, if heated further, to anhydrous calcium sulphate (anhydrite). As for anhydrite, its solubility in saline solutions and in brines is additionally strongly hooked into NaCl (common table salt) concentration.
Gypsum crystals are found to contain anion water and hydrogen bonding. The foremost common sorts of plaster mainly contain gypsum, lime, or cement, but all add an identical way. Sorts of plaster have several other uses. In medicine plaster orthopaedic casts are still often used for supporting set broken bones. In dentistry, plaster is employed to form dental impressions. Various sorts of models and moulds are made with plaster.
Plaster of Paris (POP) is formed by heating Gypsum at a temperature of 373K. it's also referred to as calcium sulphate Semi-Hydrate
Number of water molecules in plaster of Paris (POP)= 2
Number of water molecules in Gypsum= 0.5
Hence option D is the correct one.

Additional Information:
Gypsum is widely mined and is employed as a fertilizer and because it is the main constituent in many sorts of plaster, blackboard chalk, and drywall. it's moderately water-soluble and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures.

Note:
When added water to the plaster of Paris (POP), it'll re-form into gypsum. Plaster of Paris (POP) is often moulded into different shapes when it's moistened, but gypsum doesn't have that property. Gypsum may be a present mineral whereas Plaster of Paris is manufactured.