when do you use 0= delta G naught + RTlnK? I know how to use the equation to find K, but when is the equation above used?
Gibbs Free Energy and Equilibrium
(using text Chemistry the Central Science)
- pisgahchemistLv 711 months agoFavorite Answer
Gibbs free energy ....
The Gibbs free energy expression for non-standard conditions
ΔG = ΔG° + RTlnQ ........... Q is the reaction quotient(*)
If a system is at equilibrium, then ΔG = 0 an Q = K
0 = ΔG° + RTlnK
ΔG° = -RTlnK
* The expression for the reaction quotient looks just like the equilibrium expression, but does not include equilibrium concentrations. Q might be based on the initial concentrations
- 冷眼旁觀Lv 711 months ago
ΔG° = Standard Gibb's free energy (in J mol⁻¹)
R = Gas constant = 8.314 J mol⁻¹ K⁻¹
T = Temperature (in K)
K = equilibrium constant
The expression 0 = ΔG° + R T ln(K) can be used in 2 cases:
Case 1: Rearrange to ΔG° = R T ln(K)
Calculate the standard Gibb's free energy, ΔG°, at a certain temperature when the equilibrium constant, K, is known.
Case 2: Rearrange to ln(K) = ΔG° / (R T)
Calculate the equilibrium constant, K, at a certain temperature when the standard Gibb's free energy, ΔG°, is known.