2СuS + 3O2 = 2CuO + 2SO2S(-2) -6e = S(+4) 2 в-льO2(0) +4e = 2O(-2) 3 ок-ие3Mg + 4H2SO4 = 3MgSO4 + S + 4H2OMg(0) -2e = Mg(+2) 3 в-льS(+6) + 6e = S(0) 1 ок-льNaHCO3 + NaOH = Na2CO3 + H2ONa(+) + HCO3(-) + Na(+) + OH(-) = 2Na(+) + CO3(-2) + H2OHCO3(-) + OH(-) = CO3(-2) + H2OPCl3 + Cl2 = PCl5P(+3) -2e = P(+5) 1 в-льCl(0) +1e = Cl(-) 2 ок-льNa2O + Cl2O7 = 2NaClO4