ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
The Yang–Yang relation expresses the heat capacity at constant volume, CV(T,ρ), of a fluid linearly in terms of the second temperature derivatives of the pressure and the chemical potential, p″(T,ρ) and μ″(T,ρ). At a gas–liquid critical point CV diverges so, on approaching Tc from below, either pσ″(T), or μσ″(T), or both must diverge, where the subscript σ denotes the evaluation of p and μ on the phase boundary or vapor-pressure curve. However, previous theoretical and experimental studies have suggested that μσ″(T) always remains finite. To test these inferences, we present an analysis of extensive two-phase heat capacity data for propane recently published by Abdulagatov and co-workers. By careful interpolation in temperature and subsequently making linear, isothermal fits vs specific volume and vs density, we establish that the divergence is shared almost equally between the derivatives pσ″(T) and μσ″(T). A re-examination of the analysis of Gaddy and White for carbon dioxide leads to similar conclusions although the singular contribution from μσ″(T) is found to be of opposite sign and probably somewhat smaller than in propane. © 2000 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1308284
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