Mr(N2O5) = 108
W(N) = (Ar(N) * 2) / Mr(N2O5) = (14 * 2) / 108 = 0.25926 = 25.926%
W(O) = (Ar(O) * 5) / Mr(N2O5) = (16 * 5) / 108 = 0.74074 = 74.074%
ответ: W(N) = 25.926%; W(O) = 74.074%
