Journal archive > 2005 > N 1 January-February

# A new thermodynamic function, which allows easy determination of the direction of a reaction and its energetic characteristics

A new thermodynamic function, namely *a universal variable Q*, is suggested for the description of reversible chemical reactions. According to the definition, if the reaction is represented by the equation *a*A + *b*B = *g*G + *h*H, and *K* is the equilibrium constant, the universal variable *Q* is: *Q* = (*a _{G}^{g}a_{H}^{h}*)/(

*a*). Then,

_{A}^{a}a_{B}^{b}K*Q*is a dimensionless variable, which has the following properties:

*Q*= 1 for the state of equilibrium,

*Q*< 1 for spontaneous reactions, and

*Q*> 1 for the reverse reaction. Knowledge of

*Q*allows determination of the Gibbs energy and standard Gibbs energy by the same formula: ?G =

*RT*ln

*Q*.

Recieved: 2004-11-12

Published at the site: 2005-02-02

The original article in Ukrainian is available for download in PDF format.