Virial equation of state of helium, xenon, and helium-xenon mixtures from speed-of-sound and burnett P ρ T measurements

The virial equation of state was determined for helium, xenon, and helium xenon mixtures for the pressure and temperature ranges 0.5 to 5 MPa and 210 to 400 K. Two independent experinaental techniques were employed: Burnett PpT measurements and speed-of-sound measurements. The temperaturedependent second and third density virial coefficients for pure xenon and the second and third iInteraction density viria[ coefficients for helium xenon mixtures were determined. The present density virial equations of state for xenon and helium-xenon naixtures reproduce the speed-of-sound data within 0.01% and the PpT data within 0.02% of the pressures. All the results for helium are consistent, within experimental errors, with recent ab initio calculations, confirming the accuracy of the experimental techniques.