Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4⋅xH2O, where x indicates the number of moles of H2O per mole of MgSO4. When 6.073 g of this hydrate is heated to 250 ∘C, all the water of hydration is lost, leaving 2.966 g of MgSO4.

Question

What is the value of x?

Answer 1

molar mass MgSO4 ... 120.4 g
... moles MgSO4 ... 2.966 g / 120.4 g

molar mass H2O ... 18.02 g
... moles H2O ... (6.073 g - 2.966 g) / 18.02 g

x = (moles H2O) / (moles MgSO4)