Объяснение:
Mr(H2S) = 1*2 + 32 = 34
Mr(SO3) = 32 + 16*3 = 80
Mr(Al2O3) = 27*2 +16*3 =102
Mr(H2SO4) = 1*2 +32 + 16*4 = 98
Mr(Ca(NO3)2 = 40 + 14*2 + 16*6 =164
Mr(P2O5) = 31*2 + 16*5 = 142
Mr(Ca3(PO4)2) = 40*3 + 31*2 + 16*8 =310
