How would you determine if a reaction is entropy driven or enthalpy driven?

1 Answer
Aug 18, 2017

Answer:

We calculate entropy change, #DeltaS#, by standard summation.

Explanation:

#DeltaS^@""_"reaction"# is given by.......

#SigmaS^@{"products"}-SigmaS^@{"reactants"}#

And a similar summation gives you the enthalpy change. The single, unequivocal' criterion for the spontaneity of chemical change is give by #DeltaG^@=DeltaH^@-TDeltaS^@#.

#DeltaG#, the Gibbs free energy, can also be related to the thermodynamic equilibrium constant, i.e. #DeltaG=-RTln{K_"eq"}#.

And thus you need values for both enthalpy and entropy change for a given reaction. Most of the time entropy is the dominant term, but you need data for a given reaction.