Thermodynamics of sublimation of zinc chloride investigated by the mass-spectrometric method

Abstract

The vapour pressures of solid zinc chloride were measured by Knudsen effusion-mass spectrometry, and are expressed by ln p Pa = −(17760 ± 210)( K T ) +(30.92 ± 0.41) at temperatures from 455 to 570 K. The second-law enthalpy of sublimation Δ s s H m o(298.15 K) is (150.2 ± 1.7) kJ·mol −1, and the third-law value is (149.1 ± 0.7) kJ·mol −1. The corresponding values of Δ s s S m o(298.15 K) are 167.7 and 165.4 J·K −1·mol −1.