In the conversion of limestone to lime,
CaCO3(s)→CaO(s)+CO2(g)
the values of ΔHo and ΔSo are +179.1kJmol−1 and 160.2kJmol−1 respectively at 298K and 1 bar. Assuming that, ΔHo and ΔSo do not change with temperature; temperature above which conversion of limestone to lime will be spontaneous is: