Subject: CCL:SUMMARY:Equilibrium Constants

From: knauerc <[email-masked]>
Date: Thu, 08 Aug 2002 15:28:26 -0400

Thanks to everyone for your help, and my apologies for being
so late in posting this summary of responses.

My question was:

Does anyone know where I can find good data for the equilibrium
constants, (as a function of temperature), for the reactions:

H2 + Cl2 = 2HCl

and

H2 + Br2 = 2HBr

The answers I received were:

1) Abhishek Jha ([email-masked])

Hi!
Try www.nist.gov
I have used this before so I am sure you will get what you are looking
for.  Best of luck!

Cheers!
Abhishek Jha

2) Wayne Steinmetz ([email-masked])

Consider using the JANF Thermochemical Tables.

3) Bill Smith ([email-masked])

Apart from standard tables like the JANAF Tables
(CHASE,M.,Jr.,1998, {\it NIST-JANAF Thermochemical Tables, 4th ed., J. Phys. and
Chem. Reference Data Monograph No. 9,} (Am. Chem. Society, Am. Inst.
Physics).Data, you can get a lot of this data from the free Lite version of the
reaction equilibrium software package EQS4WIN, available at

http://www.mathtrek.com

4) Chuck McFarland ([email-masked])

Given that enthalpy and entropy easily lead to free energies, which in turn lead
to equilibrium constants, and that Shomate equation coefficients give
temperature dependence, most, if not all, of what you need is at

http://webbook.nist.gov/chemistry/

5) David Shobe ([email-masked])

The NIST WebBook (http://webbook.nist.gov/chemistry/) has thermochemical data as
a function of temperature, and you can calculate equilibrium constants in the
usual way.

(Also note that the answers and necessary data sets will differ considerably for
gas-phase and aqueous-phase equilibrium constants).

6) Viswanathan Balakrishnan ([email-masked])

The equilibrium constants can be calculated from the thermodynamic data
available at http://webbook.nist.gov/chemistry/

7) Michael J. Zehe ([email-masked])

A convenient source of up-to-date thermodynamic data in an easily-used form is
the program PFC, at http://cea.grc.nasa.gov/.  PFC allows the user to get
accurate data for over 2000 species contained in the NASA Glenn, (formerly NASA
Lewis),database documented in NASA TP-2002-211556 and at
http://www>.grc.nasa.gov/www/ceaweb>. This database has been maintained and
documented for almost 50 years by Ms. Bonnie Mcbride et al at NASA Glenn in
support of the NASA chemical equilibrium program CEA.