-se afla nr. de moli de hidrogen
n=m:M [ n=nr.moli m=masa subst. M=masa molara ]
n=100g : 2g/moli=50 moli hidrogen
50moli xmoli
3 H2 + N2 = 2NH3
3moli 2moli
x=50 .2 :3=33,33 moli NH3
50moli ymoli
H2 + Cl2 =2 HCl
1mol 2moli
y=50 .2=100 moli HCl
b.
m=n.M
mHCl=100moli . 36,5 g/moli=3650g
ms HCl=md.100 : c
ms=3650 .100 : 20=18250 g sol. HCl