Question

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). Also determine whether the reactions in part 1 and 2 are spontaneous or nonspontaneous. 1).1095 K 2).1500K

Answer 1

The reaction

You need to calculate the standard enthalpy and entropy of the reaction:

You need the enthaply of formation an entropy from tables, for the products and reactants

         

             

                  

Assuming the enthaply and entropy doesn't change you can calculate the free energy using:

<-------notice you need to change the entropy to kJ

at 1095K

at 1500K

At

1095 the free energy is positive, thus the reaction is non-spontaneous.

At

1500 the free energy is negative, thus the reaction is spontaneous.