Equilibrium Constants from Molecular Structure


This applet uses statistical mechanics to calculate the equilibrium constant for a simple bimolecular chemical reaction involving diatomic molecules and atoms. You can use the pre-set examples or you can input your own. You can calculate Ae, Be, and Ce using the calculators at the bottom of the page.

Fill in the values: (You can put a space between the elements, e.g. H 35Cl )
A + B -> C + D
Ae (cm-1)
Be (cm-1)
Ce (cm-1)
symm. number
vo (cm-1)
ground state degeneracy
Do, dissociation E (eV)
or choose
mass (g/mol)
H-H(0) (kJ/mol)
S (J/mol/K)
G-G(0) [internal] (kJ/mol)
G-G(0) (kJ/mol)
G(0) (kJ/mol)
G (kJ/mol)

Final reaction Gibbs Free Energy change: kJ    and Kp:

Polyatomic Be Calculator   ABC

Diatomic Be Calculator

Calculate Be from the bond length for a diatomic molecule. Put in the new molecule and bond length and then click outside the ro dialog box. Click on "Transfer to ->" to put your new Be in the main form. For Diatomics set Ae and Ce = 0.

formula:     ro (ang):     Be (cm-1) :

Transfer to

Allowable element names are:

with the element symbol without the mass number, the most abundant isotope. For example, H = 1H, S = 32S, and Cl = 35Cl.
A simpler version of this applet for Diatomics is also available.
Colby College, T. W. Shattuck, 5/4/04