Mg(OH)²
-se calculeaza masa molara
M=24+2.16+2=58-------->58g/moli
-se calculeaza comp.proc.prin masa molara
58g.Mg(OH)²-----------24g
Mg----------32g
o------2gh
100g----------x--------y-----z
x=100.24:58=41,38%mg
y=100.32:58=55,17%O
x=100.2:58=3.45%H
