2Cu + O2 =t= 2CuO

CuO + 2HCl = CuCl2 + H2O

CuCl2 + 2NaOH = Cu(OH)2↓ + 2NaCl

Cu(OH)2 + 2HCl = CuCl2 + 2H2O

Zn + CuCl2 = ZnCl2 + Cu↓