1)Ca->Ca2(OH)->CaO->CaCl2->Ca

2)CuCl2->Cu->CuO->CuCl2->Cu(Oh)2->CuO

Сa + 2H2O = Ca(OH)2 + H2

Ca((OH)2 =t= CaO +H2O

CaO + 2HCl = CaCl2 + H2O

CaCl2 =эл. ток = Сa + Сl2  

CuCl2 + Mg = Cu + MgCl2

2Cu + O2 =t= 2CuO

CuO +  2HCl = CuCl2 + H2O

CuCl2 + 2NaOH = Cu(OH)2 + 2 NaCl 

Cu(OH)2 =t= CuO + H2O