### Liquid-vapor equilibrium in binary systems for He in n-H{sub 2}, HD, and n-D{sub 2} under ordinary pressureLiquid-vapor equilibrium in binary systems for He in n-H{sub 2}, HD, and n-D{sub 2} under ordinary pressure

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 Author Yamanishi, Toshihiko ♦ Okuno, Kenji ♦ Naruse, Yugi ♦ Sada ♦ Eizo Sponsorship USDOE Source United States Department of Energy Office of Scientific and Technical Information Content type Text Language English
 Subject Keyword CHEMISTRY ♦ HELIUM ♦ EQUILIBRIUM ♦ HYDROGEN ♦ DEUTERIUM ♦ LIQUIDS ♦ VAPORS ♦ TEMPERATURE DEPENDENCE ♦ TEMPERATURE RANGE 0013-0065 K ♦ PRESSURE DEPENDENCE ♦ LOW PRESSURE ♦ MEDIUM PRESSURE ♦ MATHEMATICAL MODELS Abstract The liquid-vapor equilibrium in binary systems for He in n-H{sub 2}, HD, and n-D{sub 2} has been measured in the range 15-25 K under ordinary pressure (40-170 kPa). Helium mole fractions in the liquid phase presented linear dependence on the He partial pressure within the precision of composition measurements for all the systems: the systems obeyed Henrys law. The Henrys law constant K was expressed by a empirical formula by arranging the experimental data: K=F{sub 1}(T) exp(F{sub 2}(T)/RT) where R and T are the gas constant and temperature, respectively. The functions F{sub 1} and F{sub 2} were expressed by the first-order functions of temperature: F{sub 1}(T)=f{sub 1} + f{sub 2}T and F{sub 2}(T)=f{sub 3}+f{sub 4}T. The values of functions F{sub 1} and F{sub 2} and the Henrys law constants experimentally determined agree approximately with those estimated by regular solution theory. Agreements of the calculated result using the above equation with some previous data were also demonstrated for corresponding liquid-vapor equilibrium. Enhancement factors which define deviation from Raoults law were experimentally determined for hydrogen isotopes. The thermodynamic equation evaluating the enhancement factors was also derived under an assumption that equations of state for the vapor phase could be expressed by virial equations using the second virial coefficients alone. The calculated values were in approximate agreement with those experimentally determined. 25 refs., 5 figs., 5 tabs. ISSN 00223654 Educational Use Research Learning Resource Type Article Publisher Date 1992-03-05 Publisher Place United States Journal Journal of Physical Chemistry Volume Number 96 Issue Number 5