10. Рассчитайте относительную молекулярную массу веществ: а) B(OH)₃, PCl₃, CuCl₂, SiCl₄; б) P₂O₅, Cl₂O₇, N₂O₅, Al₂S₃; в) K₃PO₄, K₂SO₃, Na₂SO₄, AgNO₃; г*) Zn(NO₃)₂, Cu(OH)₂, Fe(OH)₃, Al₂(SO₄)₃; д*) CuSO₄·5H₂O, Na₂CO₃·10H₂O.

Используем относительные атомные массы: H = 1, C = 12, N = 14, O = 16, Na = 23, Al = 27, P = 31, S = 32, Cl = 35,5, K = 39, Fe = 56, Cu = 64, Zn = 65, Ag = 108, Si = 28.

1. а)

   • M_r(B(OH)₃) = 11 + 3 × (16 + 1) = 62.
   • M_r(PCl₃) = 31 + 3 × 35,5 = 137,5.
   • M_r(CuCl₂) = 64 + 2 × 35,5 = 135.
   • M_r(SiCl₄) = 28 + 4 × 35,5 = 170.

2. б)

   • M_r(P₂O₅) = 2 × 31 + 5 × 16 = 142.
   • M_r(Cl₂O₇) = 2 × 35,5 + 7 × 16 = 183.
   • M_r(N₂O₅) = 2 × 14 + 5 × 16 = 108.
   • M_r(Al₂S₃) = 2 × 27 + 3 × 32 = 150.

3. в)

   • M_r(K₃PO₄) = 3 × 39 + 31 + 4 × 16 = 212.
   • M_r(K₂SO₃) = 2 × 39 + 32 + 3 × 16 = 158.
   • M_r(Na₂SO₄) = 2 × 23 + 32 + 4 × 16 = 142.
   • M_r(AgNO₃) = 108 + 14 + 3 × 16 = 170.

4. г*)

   • M_r(Zn(NO₃)₂) = 65 + 2 × (14 + 3 × 16) = 189.
   • M_r(Cu(OH)₂) = 64 + 2 × (16 + 1) = 98.
   • M_r(Fe(OH)₃) = 56 + 3 × (16 + 1) = 107.
   • M_r(Al₂(SO₄)₃) = 2 × 27 + 3 × (32 + 4 × 16) = 342.

5. д*)

   • M_r(CuSO₄·5H₂O) = 64 + 32 + 4 × 16 + 5 × (2 × 1 + 16) = 250.
   • M_r(Na₂CO₃·10H₂O) = 2 × 23 + 12 + 3 × 16 + 10 × (2 × 1 + 16) = 286.