Сu-->CuO-->x-->Cu(OH)2-->y-->Cu
2Cu+O2=2CuO
CuO+2HCl=CuCl2+H2O
CuCl2+2NaOH=Cu(OH)2+2NaCl
Cu(OH)2=CuO+H2O
CuO+H2=Cu+H2O