Ha> HB: the reaction a-B is spontaneous uB>HA: the reaction B>A is spontaneous ua- uB: neither direction, A,G=0 65 △G<0 △G>0 △G=0 Extent of reaction, 5
A > B : the reaction A→B is spontaneous B > A : the reaction B → A is spontaneous A = B : neither direction, rG = 0 Extent of reaction, Gibbs energy, G rG < 0 rG > 0 rG = 0
AG<0, the forward reaction is spontaneous, called exergonic(work producing) AG>0, the reverse reaction is spontaneous, called endergonic"(work consuming, e.g., eletrolysing water to H, and O2) G=0, reaction at equilibrium, neither exergonic nor endergonic
rG < 0, the forward reaction is spontaneous, called “exergonic” (work producing) rG > 0, the reverse reaction is spontaneous, called “endergonic” (work consuming, e.g., eletrolysing water to H2 and O2 ) rG = 0, reaction at equilibrium, neither exergonic nor endergonic
Perfect Gas Equilibria △G=pB-FA (uB+RTin PB)-(A+RTIn pa =△G+RTln2B PA =△G°+ RTIn Q 0, pure A reaction guotient oo, pure B
Perfect Gas Equilibria ( ln ln ) ( ) ln ln r B A B B A A B r A r G RT P RT P P G RT P G RT Q = − = + − + = + = + “reaction quotient” 0, pure A , pure B
The Standard Reaction Gibbs Energy, AGo Like the standard reaction enthalpy, defined as the difference in the standard molar gibbs energies of the reactants and products B =△G-△G0
The Standard Reaction Gibbs Energy, rG Like the standard reaction enthalpy, defined as the difference in the standard molar Gibbs energies of the reactants and products. r B m A m , , f B f A G G G G G = − = −
At equilibrium,△G=0, 0=△G6+ rTIn k RT In K=-△G K=(PR/PA B Equilibrium equilibrium tables of constant thermodynamic data
At equilibrium, rG = 0, 0 = rG + RT ln K RT ln K = – rG K = (PB /PA)equilibrium tables of thermodynamic data equilibrium constant