ISSN:
1572-9567
Keywords:
1-chloro-1,2,2,2-tetrafluoroethane
;
2,2-dichloro-1,1,1-trifluoroethane
;
heat capacity
;
R123
;
R124
;
vapor pressure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Molar heat capacities at a constant volume (C v) of 2,2-dichloro-1,1,1-trifluoroethane (R123) and 1-chloro-1,2,2,2-tetrafluoroethane (R124) were measured with an adiabatic calorimeter. Temperatures ranged from 167 K for R123 and from 94 K for R124 to 341 K, and pressures were up to 33 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of a high purity, verified by chemical analysis of each fluid. For the samples, calorimetric results were obtained for two-phase (C (2) v), saturated liquid (C σ or C′ x ), and single-phase (C v) molar heat capacities. The C σ data were used to estimate vapor pressures for values less than 100 kPa by applying a thermodynamic relationship between the saturated liquid heat capacity and the temperature derivatives of the vapor pressure. Due to the tendency of both R123 and R124 to subcool, the triple-point temperature (T tr) and the enthalpy of fusion (Δ fus H) could not be measured. The principal sources of uncertainty are the temperature rise measurement and the change-of-volume work adjustment. The expanded uncertainty (at the 2σ level) for C v is estimated to be 0.7%, for C (2) v it is 0.5%, and for C σ it is 0.7%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006717110887
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