## Gibbs Free Energy and K

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Fatemah Yacoub 1F
Posts: 114
Joined: Thu Jul 11, 2019 12:16 am

### Gibbs Free Energy and K

Can someone explain the free energy depends on pressure and the equilibrium constant

Isha_Maniyar_Dis2E
Posts: 110
Joined: Thu Jul 11, 2019 12:16 am

### Re: Gibbs Free Energy and K

You can relate Gibbs free energy to K using the following equation:

∆Gº = -RTlnK

As you can see, this is not dependent on pressure or temperature. However, the max work that can be done is given by ∆G at constant pressure and temperature.

Hope this helped!

Kassidy Ford 1I
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Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 1 time

### Re: Gibbs Free Energy and K

Isha_Maniyar_Dis2E wrote:You can relate Gibbs free energy to K using the following equation:

∆Gº = -RTlnK

As you can see, this is not dependent on pressure or temperature. However, the max work that can be done is given by ∆G at constant pressure and temperature.

Hope this helped!

You said that this isnt dependent on temperature, but doesnt the T in the equation stand for temperature? also wouldn't K change if the temperature changed?

MAC 4G
Posts: 121
Joined: Wed Sep 18, 2019 12:16 am

### Re: Gibbs Free Energy and K

Kassidy Ford 1I wrote:
Isha_Maniyar_Dis2E wrote:You can relate Gibbs free energy to K using the following equation:

∆Gº = -RTlnK

As you can see, this is not dependent on pressure or temperature. However, the max work that can be done is given by ∆G at constant pressure and temperature.

Hope this helped!

You said that this isnt dependent on temperature, but doesnt the T in the equation stand for temperature? also wouldn't K change if the temperature changed?

Yes, the T does stand for temperature, but I don't think the value of K wouldn't change if the temperature changed being K=[P]/[R]. The equation is referring to the system being at a constant temperature, and I'm not sure exactly how to explain it, but I'll try. Gibbs energy is the chemical potential that is minimized when a system reaches equilibrium at constant pressure and temperature. As such, it is a convenient criterion of spontaneity. And Gibbs free energy and spontaneity depends on the value of K. For instance, if you have a small K value and a positive delta G, you'll have a non-spontaneous system.

Megan Kirschner
Posts: 46
Joined: Wed Feb 20, 2019 12:17 am

### Re: Gibbs Free Energy and K

Gibbs energy is like a chemical potential that is reduced to its minimum when a system reaches eq. at constant pressure and temperature. Gibbs and K are related because they can tell us what is likely happen in a reaction.

AKatukota
Posts: 100
Joined: Thu Jul 25, 2019 12:18 am

### Re: Gibbs Free Energy and K

So for example question 5G.13 in the textbook, how would you find Gibbs free energy when given K, temperature, and there pressures of the products and reactants?