Рассчитать Mr (Cu(NO3)2) и массовые доли элементов

Mr(Cu(NO3)2) = Mr = Ar(Cu) + 2Ar(N) + 6Ar(O) = 64 + 2 * 14 + 6 * 16 = 188

w(Cu) = Ar(Cu) / Mr = 64 / 188 = 0.3404 = 34.04%

w(N) = 2Ar(N) / Mr = 28 / 188 = 0.1489 = 14.89%

w(O) = 6Ar(O) / Mr = 96 / 188 = 0.5107 = 51.07%