How does delta G change with pressure?

1 Answer
Sep 22, 2015

DeltaG=DeltaG^@+RTln(((P_(NH_3))^2)/(P_(N_2)*(P_(H_2))^3))ΔG=ΔG+RTln((PNH3)2PN2(PH2)3)

Explanation:

The relationship between DeltaGΔG and pressure is: DeltaG=DeltaG^@+RTlnQΔG=ΔG+RTlnQ

Where QQ is the reaction quotient, that in case of a reaction involving gaseous reactants and products, pressure could be used.

For example: N_2(g) + 3H_2(g) -> 2NH_3(g)N2(g)+3H2(g)2NH3(g)

The reaction quotient is: Q=((P_(NH_3))^2)/(P_(N_2)*(P_(H_2))^3)Q=(PNH3)2PN2(PH2)3

Therefore, DeltaG=DeltaG^@+RTln(((P_(NH_3))^2)/(P_(N_2)*(P_(H_2))^3))ΔG=ΔG+RTln((PNH3)2PN2(PH2)3)

I recommend this video that explains this concept in details: