Introduction

Abstract

The primary purpose of tables of thermochemical data is to enable chemists to explain why a given process occurs or alternatively, to allow them to predict which chemical processes are thermodynamically feasible using the equation:

$$\Delta {G^\theta } = \Delta {H^\theta } - T\Delta {S^\theta } = - RT1n{K_a}$$

where ΔG^θ,ΔH^θ; and ΔS^θ are the standard Gibbs energy, enthalpy and entropy changes for the process concerned. K_a is the equilibrium constant in terms of activities and is a quantitative measure of the allowed maximum extent of a chemical reaction if equilibrium is attained. Values of ΔH^θ and ΔS^θ can be calculated from tabulated values for the standard enthalpies of formation and entropies of the species involved in the process.