Ca-->Ca(OH)2-->CaCO3-->CaO-->CaSO4-->CaCl2-->Ca(OH)2
1) Ca +2H2O = Ca(OH)2 + H2
2) CaOH2+CO2 = CaCO3+H2O
3)CaCO3 =t= CaO + CO2
4) CaO +H2SO4 = CaSO4(осадок) + H2O
5) CaSO4+4СО =700-800 град С= CaS +4СО2
CaS+2HCl(разб)=CaCl2+H2S
6) CaCl2 + 2NaOH = Ca(OH)2 + 2NaCl