Question

Cu->CuO->CuSO4->Cu(OH)2->CuO->Cu

Answer 1

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