Sound Velocity, Adiabatic Compressibility, and Specific Heat of Liquid and Dense Fluid Krypton

Abstract

The sound velocity, W, in liquid and dense fluid krypton has been measured with an estimated accuracy of 0.2%, using a double-transducer acoustic interferometer operating in the frequency range 1.05–1.44 MHz. Measurements have been made over the temperature range 145–240°K, and at pressures up to 680 atm. The results show good agreement with published data for pressures below 68 atm. Measurements at the critical temperature, 209.4°K, and at several nearby temperatures, provide information about the form of W–P–T and W–V–T surfaces near the critical point. Smoothed values of W have been used, together with published P–V–T data, to derive adiabatic compressibilities and constant-pressure and constant-volume specific heats for liquid krypton. The calculated specific heats, which have an estimated accuracy of 5%, show good agreement with the calorimetric measurements of Gladun and Menzel for the saturated liquid. However, our results suggest that Cv for liquid krypton is not independent of temperature in the region adjacent to the saturation line, as Gladun and Menzel have reported.