Consider the following reaction:

CaCO3 (s) →CaO (s) + CO2 (g).

Estimate ΔG∘ for this reaction at each of the following temperatures. (Assume that ΔH∘ and ΔS∘ do not change too much within the given temperature range.)

300K

1000K

1440K

Well even though im not giving you the whole answer, Im going to tell you what to do in order for you to do it. The main thing you need to do is to determine the delta H and delta S for the reaction. Then subtract the reactants from the products.

On eexample of this is: Delta H = (-634.9 (CaO) + - 393.5 (CO2)) - (-1207.6 (CaCO3)) = 179.2 kJ

Do the same thing for Delta S but make sure you use the correct units. Delta S is in Joules so you may need to convert. Once you have those values, plug into the equation

Delta G = Delta H - T * Delta S

And you will get your result

hope this is very useful for you