Răspuns:
FeS compus in care Fe are valenta II
miu(M)= (56gFe + 32gS)/mol= 88g/mol
in 88g compus........56gFe........32gS
100g...............................x.......................y
x=100x56/88=63,6% Fe
y= 100x32/88=36,4%S
Fe2S3 este compusul in care Fe are valenta III
URMARESTE calculul de mai sus si aplica-l la acest compus; ai grija ca x+y=100
Explicație: