| Moles of anhydrous MgSO4 is the number of grams divided by the molecular mass:
2.5g / (24.3 + 32.1 + 64.0) = 2.5 / 120.4 = 0.0208 moles
The moles of water driven off is the mass of water driven off divided by the molecular mass of water:
2.5 / 18.0 = 0.139 moles
Round to the correct number of significant figures. |