A simplification of gas clathrate hydrate thermochemistry using the Thermodynamic Difference Rule (TDR). Part 3. Heat capacity prediction as compared with experimental Cp values - Towards further validation of the TDR approach

To date the Thermodynamic Difference Rule (TDR) has proved itself to be highly satisfactory as a means of establishing unknown thermodynamic data. In Parts 1 (Jenkins, 2017) and 2 (Jenkins, 2017) we demonstrated the successful prediction of ΔfHo data for gas clathrate hydrates using TDR. In the absence of any experimental standard Gibbs free energy, ΔfGo or standard entropy, S298o data suggestions were made (based on experience with conventional inorganic hydrates) of likely forms of TDR equations which might predict these missing thermodynamic values. In the present paper, in view of the availability of a few experimental heat capacity values, we test the applicability of a similar suggested form of TDR for Cp prediction against the experimental values. Despite the fact that an absolute comparison cannot actually be achieved, closeness of predicted and (extrapolated) experimental values compare well. The result suggests that our previous TDR equations for the prediction of ΔfGo and S298o are likely to be highly reliable.