Răspuns:
Mr(KOH) = A(K) + A(O) + A(H) = 39 + 16 + 1 = 56 u.
Mr(H₂SO₄) = 2 × A(H) + A(S) + 4 × A(O) = 2 × 1 + 32 + 4 × 16 = 98 u.
Mr(H₃PO₄) = 3 × A(H) + A(P) + 4 × A(O) = 3 × 1 + 31 + 4 × 16 = 98 u.
Mr(Ca(NO₂)₂) = A(Ca) + 2 × A(N) + 4 × A(O) = 40 + 2 × 14 + 4 × 16 = 132 u.
Mr(FeCl₃) = A(Fe) + 3 × A(Cl) = 56 + 3 × 35,5 = 162,5 u.
Mr(Al₂O₃) = 2 × A(Al) + 3 × A(O) = 2 × 27 + 3 × 16 = 102 u.
Mr(P₂O₃) = 2 × A(P) + 3 × A(O) = 2 × 31 + 3 × 16 = 110 u.
-Mihai
