Find the total percentage of oxygen in magnesium nitrate crystal Mg(NO3)2·6H2O.
[H = 1, N = 14, O = 16, Mg = 24]
Mass of oxygen present in magnesium nitrate crystal = [(616) + (616)] g = 192 g
Molecular mass of Mg(NO3)2·6H2O = [24 + 2 (14+48) + 6 (18)] g = 256 g