| Abstract
| - Speeds of sound in the liquid phase of 1,1-difluoroethane, CHF2CH3, were measured by a sing-aroundtechnique operated at a frequency of 2 MHz. The results cover the temperature range along six isothermsfrom (243 to 333) K and pressures from near the saturation line to about 30 MPa. The combineduncertainty is estimated to be within ±0.2% except for the region near the coexistence line in the uppertemperature range. The vapor pressure was also measured with an uncertainty lower than ±20 kPa bydetecting the phase change using an acoustic absorption technique. The speeds of sound in the saturatedliquid were estimated by the extrapolation to the vapor pressure from those in the compressed liquid.The temperature and/or pressure effects on the speed of sound are discussed and compared with data forsome other hydrofluorocarbons reported elsewhere.
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