Formulations for the Thermodynamic Properties of Pure Substances

2003 ◽  
Author(s):  
George A. Adebiyi
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Constant Pressure ◽  
Equations Of State ◽  
Property Values ◽  
Complete Analysis ◽  
Specific Heat Data ◽  
Pvt Data ◽  
Pure Substances ◽  
Heat Data

Complete analysis of thermodynamic systems generally requires knowledge of the property values of substances at different states. Performing such analysis on the computer is facilitated if the equations of state for the substances are available in relatively simple analytic forms. This article presents a procedure for formulation for the thermodynamic properties of pure substances using two primary sets of data, namely the pvT data and the specific heat data such as the constant-pressure specific heat, cp, as a function of pressure and temperature. By developing a correlation of the pvT data in the virial form of equation of state, an appropriate corresponding correlation can be determined for the specific heat of the substance on the basis of the laws of thermodynamics. The resulting equations of state take on remarkably simple analytic forms that give accurate predictions over the range of input data employed.

Formulations for the Thermodynamic Properties of Pure Substances

2005 ◽  
Vol 127 (1) ◽  
pp. 83-87 ◽  
Author(s):  
George A. Adebiyi
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Constant Pressure ◽  
Equations Of State ◽  
Virial Coefficients ◽  
Data Correlation ◽  
Specific Heat Data ◽  
Pvt Data ◽  
Pure Substances ◽  
Heat Data

This article presents a procedure for formulation for the thermodynamic properties of pure substances using two primary sets of data, namely, the pvT data and the specific heat data, such as the constant-pressure specific heat cp as a function of pressure and temperature. The method makes use of a linkage, on the basis of the laws of thermodynamics, between the virial coefficients for the pvT data correlation and those for the corresponding specific heat data correlation for the substance. The resulting equations of state take on remarkably simple analytic forms that give accurate predictions over the range of input data employed.

Thermodynamic Properties of Natural Rubber and Isoprene

1966 ◽  
Vol 39 (1) ◽  
pp. 143-148 ◽  
Author(s):  
R. W. Warfield ◽  
M. C. Petree
Keyword(s):  
Free Energy ◽  
Glass Transition ◽  
Thermodynamic Properties ◽  
Natural Rubber ◽  
Specific Heat ◽  
Gibbs Free Energy ◽  
Kcal Mole ◽  
Specific Heat Data ◽  
Temperature Range ◽  
Heat Data

Abstract Using published specific heat data, the entropy, enthalpy, and Gibbs free energy of natural rubber (NR) have been calculated over the temperature range 0 to 320° K. The thermodynamic function Cp/T as a function of T calculated for NR exhibits a maximum at 50° K and another maximum at 210° K, which is associated with the glass transition. The number of classically vibrating units per repeating unit of NR is 6.61 at 300° K. These functions have also been calculated for isoprene over the temperature range 0 to 300° K. At 298.16° K the entropy of polymerization was found to be 24.00 cal mole−1deg−1 and the free energy of polymerization − 10.7 kcal/mole.

A Rational Equation of State for Water and Water Vapor in the Critical Region

1964 ◽  
Vol 86 (3) ◽  
pp. 320-326 ◽  
Author(s):  
E. S. Nowak
Keyword(s):  
Water Vapor ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Critical Point ◽  
Critical Region ◽  
Constant Pressure ◽  
Parametric Equation ◽  
Enthalpy And Entropy ◽  
Specific Volumes

A parametric equation of state was derived for water and water vapor in the critical region from experimental P-V-T data. It is valid in that part of the critical region encompassed by pressures from 3000 to 4000 psia, specific volumes from 0.0400 to 0.1100 ft3/lb, and temperatures from 698 to 752 deg F. The equation of state satisfies all of the known conditions at the critical point. It also satisfies the conditions along certain of the boundaries which probably separate “supercritical liquid” from “supercritical vapor.” The equation of state, though quite simple in form, is probably superior to any equation heretofore derived for water and water vapor in the critical region. Specifically, the deviations between the measured and computed values of pressure in the large majority of the cases were within three parts in one thousand. This coincides approximately with the overall uncertainty in P-V-T measurements. In view of these factors, the author recommends that the equation be used to derive values for such thermodynamic properties as specific heat at constant pressure, enthalpy, and entropy in the critical region.

Specific heat data of high-Tc superconductors: Lattice and electronic contributions

1989 ◽  
Vol 69 (6) ◽  
pp. 625-629 ◽  
Author(s):  
J.E. Gordon ◽  
M.L. Tan ◽  
R.A. Fisher ◽  
N.E. Phillips
Keyword(s):  
Specific Heat ◽  
High Tc Superconductors ◽  
Specific Heat Data ◽  
High Tc ◽  
Heat Data

Fast Dynamics in Glass-Formers: Relation to Fragility and the Kohlrausch Exponent

1996 ◽  
Vol 455 ◽  
Author(s):  
K. L. Ngai ◽  
C. M. Roland
Keyword(s):  
Relaxation Time ◽  
Low Temperature ◽  
Specific Heat ◽  
Raman Spectra ◽  
Low Temperatures ◽  
Coupling Model ◽  
Boson Peak ◽  
Specific Heat Data ◽  
Low Temperature Specific Heat ◽  
Heat Data

ABSTRACTFrom the Raman spectra and related inferences from low temperature specific heat data, Sokolov and coworkers have established that the ratio of the quasielastic and vibrational contributions at low temperatures (5∼10K) up to Tg correlates well with the degree of fragility and β of the glass-former. As pointed out by Sokolov (see his contribution in this Volume) such a correlation between the fast dynamics and structural a-relaxation at Tg(i.e., m and β) is intriguing, since at and below Tg, the α-relaxation time τα is more than twelve orders of magnitude longer than the quasielastic contribution and the boson peak. We show in this paper how the Coupling Model (CM) may provide an explanation for this correlation.

Comparison of the prediction power of 23 generalized equations of state: Part I. Saturated thermodynamic properties of 102 pure substances

2010 ◽  
Vol 288 (1-2) ◽  
pp. 67-82 ◽  
Author(s):  
F. Abdollahi-Demneh ◽  
M.A. Moosavian ◽  
M.M. Montazer-Rahmati ◽  
M.R. Omidkhah ◽  
H. Bahmaniar
Keyword(s):  
Thermodynamic Properties ◽  
Equations Of State ◽  
Generalized Equations ◽  
Pure Substances
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