SPEED OF SOUND AND IDEAL-GAS HEAT-CAPACITY AT CONSTANT-PRESSURE OF GASEOUS TRIFLUOROIODOMETHANE (CF3I)

The speed of sound of the gaseous trifluoroiodomethane (CF3I) was meas ured for temperatures from 273.15 to 333.15 K and pressures from 58 to 276 kPa with a cylindrical, variable-path acoustic interferometer ope rating at 156.252 kHz. The uncertainty of the speed of sound was less than +/-0.1%. The ideal-gas heat capacity at constant pressure and the second acoustic virial coefficients were determined over the temperat ure range from the speed of sound measurements. The ideal-gas heat cap acity at constant pressure and second virial coefficients calculated f rom the present speed of sound measurements were compared with the ava ilable data. The uncertainty of the ideal-gas heat capacity at constan t pressure was estimated to be less than +/- 1%. (C) 1997 Elsevier Sci ence B.V.