Gibbs Free Energy

Standard States For Gasses & Aqueous Solutions

-1 ATM for gasses -1M for solution

Gibbs Free Energy Equation

-DeltaG=DeltaH-(T*DeltaS) -Delta G=Gibbs free energy change -Delta H=Enthalpy Change -T temperature in K -Delta S=Entropy change -Negative DeltaG favors reactions and is spontaneous

Calculating free energy for reaction

-DeltaGrxn=Sum: DeltaG f(Products) - Sum: Delta G f(reactants) -Only works at 298K

Characteristics with positive Delta G

-Does not produce useful work -Not Spontaneous -More reactant than product at equilibrium

Characteristics With Negative DeltaG

-Produces useful work -Spontaneous -More product than reactant at equilibrium

Effects of temperature on Gibbs free energy and entropy

-The reaction is spontaneous at T>273 K -The reaction is non-spontaneous at T<273 K -Reaction is equal at T=273 K

Equilibrium constant at Delta G = 0

1

Ways to calculate Delta G at non-standard temp

1)Find DeltaH and DeltaS rxn then plug them into Gibbs free energy 2)DeltaGrxn= -R T ln(Keq) R=8.314 T=Temp in K

When is a reaction spontaneous with a negative Delta S?

At lower temperature