Ideal Gas Heat Capacity Regression Coefficients

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SUMMARY

The discussion focuses on finding empirical coefficients for calculating ideal gas constant pressure heat capacities using the equation \(\frac{c^{IG}_P}{R}=A+BT+CT^{2}+DT^{-2}+ET^{3}\). The user has identified sources such as the NIST-JANAF thermochemical tables and "The Properties of Liquids and Gases" by Reid et al., but is seeking additional references specifically for this equation. They have also noted that the book "Engineering and Chemical Thermodynamics" by Koretsky contains relevant empirical constants. Suggestions for further references include works by C. A. Passut and R. P. Danner, and T. E. Daubert.

PREREQUISITES
  • Understanding of ideal gas laws and thermodynamics
  • Familiarity with empirical equations for heat capacity
  • Knowledge of the Shomate equation and its application
  • Experience with thermochemical data sources like NIST
NEXT STEPS
  • Research the empirical coefficients in "Engineering and Chemical Thermodynamics" by Koretsky
  • Explore the NIST-JANAF thermochemical tables for additional data
  • Investigate the works of C. A. Passut and R. P. Danner for relevant empirical constants
  • Examine T. E. Daubert's publications for further insights on heat capacity equations
USEFUL FOR

Chemical engineers, thermodynamics researchers, and anyone involved in the study of heat capacities and empirical data in gas thermodynamics will benefit from this discussion.

cjc0117
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I'm trying to find a comprehensive list of the empirical coefficients to be used in the following equation for calculating ideal gas constant pressure heat capacities:

\frac{c^{IG}_P}{R}=A+BT+CT^{2}+DT^{-2}+ET^{3}
(Eqn. 1)​

cPIG is the ideal gas constant pressure specific heat capacity; R is the universal gas constant; A,B,C,D,E are the empirical constants; T is temperature

I've found empirical constants for the Shomate equation (similar to Eqn. 1 above except that T is replaced with t=T/1000) for a limited number of chemicals, but I can't find this data in a table.

I've tried following links to NIST-JANAF thermochemical tables, and I've tried looking in the API Technical Data Book to no avail (it may be there but I just can't find it amongst all the other data).

"The Properties of Liquids and Gases" by Reid et al. has a comprehensive list of empirical constant but they use an equation in this form instead:

\frac{c^{IG}_P}{R}=A'+B'T+C'T^{2}+D'T^{3}+E'T^{4}
(Eqn. 2)​

I suppose I could fit data derived from Eqn. 2 to Eqn. 1 if I need to. I just want to see if I can find references that use Eqn. 1.

The table at this link, http://www.personal.utulsa.edu/~geoffrey-price/Courses/ChE7023/HeatCapacity-HeatOfFormation.pdf, and the book "Engineering and Chemical Thermodynamics" by Koretsky has empirical constants for Eqn. 1. That's all I've been able to find.

Does anybody know of any other references I could use? Thanks.
 
Last edited:
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Try C. A. Passut and R. P. Danner, Ind. Eng. Chem. Proc. Des. Dev., 11: 543, 1972 or
T. E. Daubert, Ibid., 13: 193, 1974
 

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