Iti dau exemplu la ex.1
1mol.......2mol
CO2 +2 NaOH---> Na2CO3+H2O
5mol.........n=10molNaOH
m=nxM
m=10molx40g/mol= 400g=. MASA CARE ESTE DIZOLVATA =>md
c=mdx100/ms---> ms=mdx100/c= 400x100/20=2000g
reactia la 2 Mg+ 2HCl---> MgCl2 + H2
reactia la 3 2Al + 3H2SO4---> Al2(SO4)3 + 3H2