Apparatus for the measurement of compressibility isotherms of gases up to 10 kbar: Experimental data for argon at 298.15 K

Abstract

An apparatus for the measurement of compressibility isotherms of gases up to pressures of 10 kbar and at temperatures between 273 and 350 K is described. It is based on a gas expansion method in which the pressure distortion of the experimental volume is evaluated by calibration with the measuring gas at lower pressures. The apparatus can easily be adapted for isochoric measurements over a wide temperature range. Measurements on argon at 298.15 K show that the method is capable of giving a precision of 0.02%–0.06% for the density, 0.1% for the pressure, and 2 mK for the temperature.