DENSITIES OF (XCO2+(1-X)H2O) WITH X-LESS-THAN-0.014 AT SUPERCRITICAL CONDITIONS MOLAR VOLUMES, PARTIAL MOLAR VOLUMES OF CO2 AT INFINITE DILUTION, AND EXCESS MOLAR VOLUMES

Using an improved vibrating-tube densitometer developed in our laboratory, differences in density between H2O and {xCO2 + (1 - x)H2O} for (0.001 < x < 0.015) have been measured at temperatures from 651.1 to 725.5 K at 28.0, 33.0, and 38.0 MPa. At least three different values of x were measured for each temperature. From the measurements, excess molar volumes and partial molar volumes of CO2 at infinite dilution were calculated. The partial molar volumes of CO2 at infinite dilution were very large and positive. Results showed that the mixtures, although dilute, were very non-ideal. These effects were found when the solvent compressiblity was very large in the neighborhood of the solvent critical point. The integral of the indirect pair-correlation function was nearly constant for these measurements and for similar measurements on aqueous argon, xenon, and ethene near the critical point of water. © 1990.