Response to “Comment on ‘The electrochemical Peltier heat of the standard hydrogen electrode reaction’ by Zheng Fang et al.” [Thermochimica Acta V 490 (1–2) (2009) 82–84

Abstract

In response to Rockwood's query about the standard state of electron and the handling of the entropy of electron on the absolute scale, an answer is made. Usually, the standard state for a chemical substance is specified based on a classical physical law. The standard state of electron on the absolute scale is determined according to the free electron model on the Fermi–Dirac statistics. However, the thermodynamic handling of the same particle on the different scales must be completely identical, and the difference is only designated values of the thermodynamic parameters. For the standard hydrogen electrode reaction, the electron entropy and the partial molar entropy of hydrogen ion, respectively, are 65.29 J mol −1 K −1 and zero on the conventional scale, and zero and about −22.3 J mol −1 K −1 on the absolute scale at 298.15 K. The other query, related to units used for fugacity, the conversion entropy of electron from gas-phase to metal-phase, the partial molar entropy of electron in the platinum, and the Peltier heat at the platinum/copper joint, is also expatiated.