Răspuns:
2.M(CuCl2)=64+35×2=134g/mol
M(K2S)=39×2+32=110g/mol
M(H3PO4)=1×3+31+16×4=98g/mol
M(Mg(OH)2)=24(16+1×2)=432
3.a)M(K2O)=39×2+16=94g/mol
n=m:M
n(K2O)=282g:94g/mol=3mol
b)M(MgCl2)=24+35×2=94g/mol
n(MgCl2)=95g:94g/mol=1,01mol
c)M(NH3)=14+1×3=17g/mol
n(NH3)=68g:17g/mol=4mol
