Estimation ofPT slope signs for univariant lines involving one phase of unknown entropy and the optimum univariant reaction for phase equilibrium experiments

Abstract

A concept of “Slope Entropy Limit” is proposed in this paper. With the aid of computer, a Slope Entropy Limit Table can be readily established, which will be helpful to estimating the slope signs of univariant lines involved in a multisystem with a phase of unknown entropy. Under fortunate circumstances the unknown entropy is expected to be restricted within acceptable limits based on slope sign data on some critical univariant lines. Otherwise, these critical univariant reactions are considered most optimum to be tested experimentally. A critical entropy limit can be obtained if only the slope sign of such a line is confirmed. The entropy limit thus obtained is subjected to a much less extent to uncertainties inPT measurements in comparison with entropy values derived fromPT brackets.