Speed-of-sound measurement with a spherical resonator is recognized as one of the most precise and reliable approaches to determine ideal-gas heat capacities and to reveal thermodynamic properties of rarefied gases. In this study, a spherical resonator was used to measure the speed of sound in gaseous pentafluoroethane, R125. Eighty speed-of-sound values were obtained along five isotherms from 277 K to 343 K and up to 600 kPa in pressure. In addition, c po values and second acoustic virial coefficients were determined at each temperature. Sample purity was 99.9% of the gas-chromatograh area fraction analyzed by the manufacturer. The expanded uncertainties with k = 2 are estimated at 11 mK in temperature, 0.31 kPa in pressure, and 72 ppm in speed of sound. The cpo values reported here were compared with those from spectroscopic data. The agreement between them was within ±0.2%.
ASJC Scopus subject areas
- Chemical Engineering(all)