Объяснение:
Mr(P2O5) = 31*2 + 16*5 =142
W(P) = Ar(P) *n / Mr(P2O5) *100% = 31*2 / 142 *100% =44%
W(O) = Ar(O) *n / Mr(P2O5) *100% = 16*5 / 142 *100% =56%
