How many water molecules of crystallization are present in exactly one formula unit of the substance — s Block Elements Chemistry Question

💡 Solution & Explanation

Dead burnt plaster is formed when Gypsum is heated above $393\text{ K}$. At this elevated temperature, it loses all of its water of crystallization to form completely anhydrous Calcium Sulphate ($CaSO_4$). Therefore, there are 0 water molecules.