Răspuns:
100g Fe.....................70g pur
8gFe..............................xg pur
x=8×70/100=5,6g Fe pur
MFe=56g/mol
MFeCl3=56+3×35,5=162,5g/mol
2×56g...................2×162,5g
2Fe + 3Cl2 → 2FeCl3
5,6g.......................xg FeCl3
x=5,6×2×162,5/2×56= calculeaza
Explicație: