abstract
The behavior of the isochoric heat capacity of pure fluids and the isobaric heat capacity at constant composition of binary mixtures along isothermal paths of approach to liquid-gas and liquid-liquid critical points is studied. From the complete scaling formulation of fluid-fluid criticality, explicit expressions for the critical amplitudes of the leading vertical bar Y-Y-c vertical bar(-alpha/beta) (where Y can be the density or the mole fraction) contributions are found to reveal previously discovered features of the scaling function, whereas the nature of the most important asymmetry-related terms is characterized. Data for pure toluene and for the binary mixture nitromethane-isobutanol are described within experimental uncertainty using the vertical bar Y-Y-c vertical bar(-alpha/beta) singularity plus a linear term. Extensive data for mixtures allow proper visualization of the topological features of the heat capacity-density-temperature surface in the critical region.
keywords
CRITICAL END-POINTS; LIQUID; THERMODYNAMICS; UNIVERSALITY
subject category
Chemistry; Physics
authors
Losada-Perez, P; Perez-Sanchez, G; Troncoso, J; Cerdeirina, CA
our authors
Germán Pérez-Sánchez
Junior Researcheracknowledgements
This research was supported by the Conselleria de Innovacion e Industria (Xunta de Galicia) under Grant No. PGIDIT-06PXIB3832828PR. Assistance to P.L.-P. and G.P.-S. by the "Ministerio de Educacion y Ciencia" under the "Programa Nacional de Formacion del Profesorado Universitario" (Grant Nos. AP-2004-2947 and AP-2005-1959, respectively) is greatly appreciated.