Question

Find the total percentage of Magnesium in magnesium nitrate crystals, Mg( NO₃) ₂.6H₂O. 

[Mg = 24, N = 14; O = 16 and H = 1]

Answer 1

Relative molecular mass of Mg(NO₃)₂'6H₂O 

= (24) + (14 x 2) + (16 x 6) + (12 x 1) + (6 x 16) 

=24 + 28 + 96 + 12 + 96 = 256

Amount of Mg in 256 g of magnesium nitrate = 24

% of Mg in Mg(NO₃)₂ 6H₂O = 24/256 x 100 = 9.37%