Determine the quantity of pure MgSO4 in 2.4 g of MgSO 4 ⋅ 7H 2 O MgSO4⋅7H2O

We can calculate this in the following way;

%MgSO4 in MgSO4.7H2O = [ (molar mass MgSO4/molar mass MgSO4.7H2O) ] x 100 = ?

Molar mass of MgSO4.7H2O is 246.4746 g/mol

Molar mass of MgSO4 is 120.366 g/mol.

%MgSO4 in MgSO4.7H2O = 120.366 / 246.4746 = 0.488 x 100 = 48.8

Then 2.4g x (%MgSO4/100) = 2.4 x (48.8/100) = 2.4 x 0.488 = 1.17 = 1.2g MgSO4