Molecular weight of MgSO4.7H2O is = 246.47 g
Molecular weight of MgSO4 is = 120.36 g
Hence, per cent of MgSO4 present in MgSO4.7H2O is,
=[tex] \frac{\text{Molecular weight of MgSO4}}{\text{Molecular weight of MgSO4.7H2O}} [/tex] X 100
= [tex] \frac{120.36}{246.47} [/tex] X 100
= 48.83 %
