ISOCHORIC HEAT-CAPACITY AND LIQUID-GAS COEXISTENCE CURVE OF CARBON-DIOXIDE IN THE REGION OF THE IMMEDIATE VICINITY OF THE CRITICAL-POINT

The paper contains the results of new experimental measurements of the isochoric heat capacity and the liquid-gas coexistence curve of carbon dioxide in the one-phase region near the critical point. The measurements were performed in a high temperature adiabatic calorimeter used earlier for the determination of the isochoric heat capacity of several liquids and liquid mixtures near the critical points [1, 2]. The experiments have been performed at seven isochores, namely: 461.2, 464.5, 467.5, 470.1, 477.7, 499.0, and 509.8 kg.m-3 in the neighbourhood of the critical point and the coexistence curve. The measurements were made with samples of constant mass contained in a calorimeter vessel of nearly constant volume. Uncertainties of the heat-capacity measurements are estimated to be less than 2 percent far from T(c) and 3 percent in the immediate vicinity of the critical point. The uncertainty in temperature was less than +/- 10 mK.