Volume 29, Issue 5, September 2000
Index of content:
New Equation of State for Ethylene Covering the Fluid Region for Temperatures From the Melting Line to 450 K at Pressures up to 300 MPa29(2000); http://dx.doi.org/10.1063/1.1329318View Description Hide Description
This work reviews the available data on thermodynamic properties of ethylene and presents a new equation of state in the form of a fundamental equation explicit in the Helmholtz energy. The functional form of the residual part of the Helmholtz energy was developed by using state-of-the-art linear optimization strategies. The new equation of state contains 35 coefficients which were fitted to selected data of the following properties: (a) thermal properties of the single phase and (b) of the liquid–vapor saturation curve including the Maxwell criterion, (c) speed of sound w of the single-phase region and the saturated vapor and liquid, (d) isochoric heat capacity (e) specific isobaric heat capacity of the single-phase region and of the saturated liquid, and (f) second and third thermal virial coefficients B and C. For the density, the estimated uncertainty of the new equation of state is less than ±0.02% for pressures up to 12 MPa and temperatures up to 340 K with the exception of the critical region. Outside the range mentioned above, the estimated uncertainty is less than ±0.03% for pressures up to 30 MPa and temperatures between 235 and 350 K. The new formulation shows reasonable extrapolation behavior up to very high pressures and temperatures. Independent equations for the vapor pressure, for the pressure on the sublimation and melting curve, and for the saturated-liquid and saturated-vapor densities are also included. Tables for the thermodynamic properties of ethylene from 104 to 450 K for pressures up to 300 MPa are given in the appendix.
Volumetric Ion Interaction Parameters for Single-Solute Aqueous Electrolyte Solutions at Various Temperatures29(2000); http://dx.doi.org/10.1063/1.1321053View Description Hide Description
The ion interaction approach developed by Pitzer allows the prediction of thermodynamiccharacteristics of mixed electrolytesolutions at various temperatures, if the respective parameters for each type of single electrolytesolution are known. Among such thermodynamiccharacteristics are the volumetric ones (density and apparent molal volumes). A database for the densities and the apparent molal volumes versus concentrations was developed at a temperature interval of 288.15–368.15 K using all available literature sources for each single electrolytesolution formed by various electrically neutral combinations of the following ions ( and These are the most important ions for industrial solutions as well as for natural waters. Statistical treatment was applied to this database in order to discard poor data. The proper treatment of all sound quality apparent molal volumes, in a wide range of concentrations from infinite dilution through saturation, allowed us to compute sets of volumetric ion interaction parameters ( and ) at various temperatures in a 288.15–368.15 K temperature interval. The validity of the selected sets at various temperatures was demonstrated by a comparison of the experimental and calculated densities for multiple-solute electrolytesolutions containing NaCl, KCl, and with an ionic strength reaching 9.23 that resembled Dead Sea water.
29(2000); http://dx.doi.org/10.1063/1.1329317View Description Hide Description
New equations that describe the thermodynamic properties of the system were obtained from previously published measurements for this system. The measured values included in the fitted equations spanned the range of temperatures of approximately 236–425 K for and 16–548 K for New equations and/or values for the following properties are given in the present work: (1) thermal properties of from 0 K to near the lambda transition, 548.6 K, (2) the change in chemical potential for both and in as a function of temperature, and molality, valid from 236 to 425 K, and the molality range of 0 mol⋅kg−1 to the lesser of the saturation molality or 25 mol⋅kg−1, and (3) standard-state properties for the aqueous solution process.
29(2000); http://dx.doi.org/10.1063/1.1321054View Description Hide Description
Robust, accurate, and asymptotically exact cross section formulas for all direct and dissociative electron impact ionization channels of methane and hydrogen are presented. The parameter estimation employs Bayesian inference and allows for a consistent use of data from different experiments with possibly discordant calibrations. An efficient method for the calculation of rate coefficients and their temperature derivatives is outlined.
29(2000); http://dx.doi.org/10.1063/1.1329911View Description Hide Description
The mutual solubilities and liquid–liquid equilibrium of nitromethane binary systems with liquidsolvents are reviewed. The solvents include water, inorganic compounds, and a variety of organic compounds as hydrocarbons, halogenated hydrocarbons, alcohols, acids, esters, and nitrogen compounds. A total 474 systems published through 1993 are compiled. For 39 systems sufficient data were available to allow critical evaluation. All data are expressed as mass and mole fractions as well as the originally reported units. Similar reviews of gas, liquid, and solid solubilities for other systems were published in the frame of Solubility Data Series.