Question

cu->cuo->cucl2->cu(oh)2->cuso4->cu(oh)2->cuo->cu

Answer 1

2Cu+O2=2CuO
CuO+2HCl=CuCl2+H2O
CuCl2+2NaOH=Cu(OH)2+2NaCl
Cu(OH)2+H2SO4=CuSO4+2H2O
CuSO4+2KOH=Cu(OH)2+K2SO4
Cu(OH)2=CuO+H2O
2CuO=2Cu+O2