I. Найти Mr
- Mr(Fe₂O₃) = 2 × Ar(Fe) + 3 × Ar(O) = 2 × 56 + 3 × 16 = 112 + 48 = 160
- Mr(Na₃PO₄) = 3 × Ar(Na) + Ar(P) + 4 × Ar(O) = 3 × 23 + 31 + 4 × 16 = 69 + 31 + 64 = 164
- Mr(Fe(OH)₂) = Ar(Fe) + 2 × Ar(O) + 2 × Ar(H) = 56 + 2 × 16 + 2 × 1 = 56 + 32 + 2 = 90
Ответ: Mr(Fe₂O₃) = 160; Mr(Na₃PO₄) = 164; Mr(Fe(OH)₂) = 90.