H₂+Cl₂=2HCl
Fe+3Cl₂=2FeCl₃
x= masa de clor di 40 moli
1mol......................71g
40 moli..................x
x=40*71/1=2840g Cl₂
Masa molara HCl=1*1+1*35.5=36.5
y=masa de HCl obtinuta
y=2840*2*36.5/71=2920g HCl
Masa molara FeCl₃=56*1+3*35.5=162.5
z=masa de FeCl₃ obtinut
z=2840*2*162.5/6*35.5=4333.3g FeCl₃