Question

CO2=CaCO3=Ca(HCO3)2=CaCO3=CaCl2

Answer 1

CaCO3--t-->CaO+CO2;
CO2+CaO---->CaCO3;
CaCO3+CO2+H2O----->Ca(HCO3)2;
Ca(HCO3)2+2HCl------>CaCl2+2H2O+2CO2;

Answer 2

1)CaO+CO2=CaCO3
2)CaCO3+H2O+CO2=(t)Ca(HCO3)2
3)Ca(HCO3)2=(t)CaCO3+H2O+CO2
4)CaCO3+2HCl=CaCl2+H2O+CO2