Ответ:

Используем Ar(H) = 1, Ar(N) = 14, Ar(O) = 16, Ar(K) = 39, Ar(Cl) = 35.5, Ar(Zn) = 65.

  1. Mr(HNO₃) = 1 + 14 + 3 · 16 = 63.
  2. Mr(KCl) = 39 + 35.5 = 74.5.
  3. Mr(Zn(NO₃)₂) = 65 + 2 · (14 + 3 · 16) = 65 + 124 = 189.