Pressure

[ng1D]

Does pressure affect free energy? If it does how?

[madawy]

The standard Gibbs Free Energy is calculated using the free energy of formation of each component of a reaction at standard pressure.

The Gibbs free energy equation is dependent on pressure. When a system changes from an initial state to a final state, the Gibbs free energy (ΔG) equals the work exchanged by the system with its surroundings, minus the work of the pressure force.

[Delaney Smith 1C]

Yes, if you increase the partial pressure of a product gas, ΔG becomes more positive. If you increase the partial pressure of a reactant gas, ΔG becomes more negative because of the equation ΔG=ΔGo+RTlnQ where Q equals partial pressure of products over the partial pressure of reactants.

[Matt F]

So in other words, pressure affects Gibbs Free Energy because it affects the value of Q?