Plaster of Paris Gypsum is the common name of calcium sulfate dihydrate (CaSO4 m
ID: 622732 • Letter: P
Question
Plaster of Paris Gypsum is the common name of calcium sulfate dihydrate (CaSO4 middot 2 H2O). When gypsum is heated to 150 degree C, it loses most of the water in its formula and forms plaster of Paris (CaSO4 middot 0.5 H2O): 2 CaS04 middot 2H2O(s) rightarrow 2 CaSO4 middot 0.5H2O(s) + 3 H2O(g) What is the sign of AH for making plaster of Paris from gypsum? Delta His positive because it requires energy to remove the waters of hydration. Delta H is negative because it requires energy to remove the waters of hydration. Delta H is positive because energy is released when the steam is removed. Delta H is negative because energy is released when the steam is removed.Explanation / Answer
A heat is required to remove water . dH +ve