Cu->CuO->CuSO4->Cu(OH)2->CuO->Cu
2Сu + O2 = 2CuO CuO + H2SO4 = CuSO4 + H2O CuSO4 + 2NaOH = Cu(OH)2 + Na2SO4 Cu(OH)2 = CuO + H2O CuO + H2 = Cu + H2O