Faci suma maselor atomilor componenti !!!!!!! A=masa atomica relativa
M Al2(SO4)3= 2A Al+ 3 A S+12A O =2*27+3* 32+ 12* 16=....
M MgCl2=A Mg+2A Cl=24+ 2*35,5=.....
M KCl= A K+ ACl= 39+ 35,5=....
M MgSO4= A Mg+ A S+ 4A O= 24+32+4*16=...
M NaNO3= A Na+ A N+ 3*A O= 23+14+3*16=...