FeSO4*xH2O cu masa moleculara: [152+18x]
100g cristalohidrat.........63,32 g O
[152+18x] g......................[64+16x] g O
==>x=7 FeSO4*7H2O cu M=152+126=278
278g ch..........152 g FeSO4
11,12g ch............y=6,08 g FeSO4 (md)
mH2O=V*p=388,88g
ms=11,12+388,88=400
c=6*100/400=.........