Molar Heat Capacity Cv, Vapor Pressure, and (p, rho,T) Measurements From 92 to 350 K at Pressures to 35 Mpa and a New Equation of State for Chlorotrifluoromethane (R13)

Published

January 1, 2001

Author(s)

Joe W. Magee, Stephanie L. Outcalt, James F. Ely

Abstract

Measurements of the molar heat capacity at constant volume C_v for chlorotrifluoromethane (R13) were conducted using an adiabatic method. Temperatures ranged from 95 to 338 K, and pressures were as high as 35 Mpa. Measurements of vapor pressure were made using a static technique from 250 to 302 K. Measurements of (p, p, T) properties were conducted using an isochoric method; comprehensive measurements were conducted at 15 densities which varied from dilute vapor to highly compressed liquid, at temperatures from 92 to 350 K. The R13 samples were obtained from the same sample bottle whose mole fraction purity was measured at 0.9995. A test equation of state including ancillary equations was derived using the new vapor pressures and (p,p, T) data in addition to similar published data. The equation of state is a modified Benedict-Webb-Rubin type with 32 adjustable coefficients. Acceptable agreement of C_v predictions with measurements was found. Published C_v(p, T) data suitable for direct comparison with this study do not exist. The uncertainty of the C_v values is estimated to be less than 2.0% for vapor and 0.5% for liquid. The uncertainty of the vapor pressures is 1 kPa, and that of the density measurements is 0.1%.

Citation

International Journal of Thermophysics

Volume

21

Issue

No. 5

Pub Type

Journals

Keywords

calorimeter, chlorotrifluoromethane, density, heat capacity, high pressure, liquid, measurement, vapor, vapor pressure

Citation

Magee, J. , Outcalt, S. and Ely, J. (2001), Molar Heat Capacity Cv, Vapor Pressure, and (p, rho,T) Measurements From 92 to 350 K at Pressures to 35 Mpa and a New Equation of State for Chlorotrifluoromethane (R13), International Journal of Thermophysics (Accessed July 5, 2025)