Question

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

Answer 1

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.