Thermal dissociation in terms of the second law of chemical thermodynamics

Starting from the relationship between Gibbs free energy and equilibrium constant of a chemical reaction (ECCR) and taking into account its temperature dependence according to Kirchhoff, Eq. (12), we arrive at the three-parametric Eq. (26). In going this way, we employ the relationship between the ECCR and the degree of conversion of the solid phase using Eqs. (20) and (21). We find that there is a compensating effect between the coefficients of the equation (i.e., ) in the form of a linear equation, which has been attributed to the enthalpy-entropy compensation. According to current state of knowledge, this result applies both to the chemical reactions resulting in individual chemical bond formation as well as in thermal decomposition. When the heat capacity of such chemical reactions decreases linearly along with temperature, it can adopt the value of the (arithmetic mean) average, and the negative sign determines the elements of the functional equations valid for theoretical (Eq. 26) and experimentally fit (Eq. 32) states. For calcite, several possibilities arising from equilibrium changes in the conversion rate vs. temperature are compared by taking into account the CDV L'vov theory.