ABSTRACT
The theoretical framework of thermodynamics was well established by the time National Bureau of Standards (NBS) was founded, and certain important applications, such as improving the efficiency of steam engines, had been demonstrated. However, the broad application of thermodynamics to the design and control of industrial processes had to await the accumulation and organization of a large amount of experimental data, as well as theoretical contributions from quantum mechanics and statistical mechanics. In intermediate situations, one can obtain a quantitative measure of the extent of reaction from the equilibrium constant, which is easily calculated from the tabulated standard state values. Finally, most chemical changes involve either an absorption or release of heat, and the amount of this heat may be calculated from the same data. Thus Selected Values provided an extremely powerful tool for predicting the course of chemical reactions, a goal of chemists since the earliest days of the science.
