Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ideal Gas Heat Capacity Regression Coefficients

  1. May 15, 2013 #1
    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:

    (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:

    (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: May 15, 2013
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted