# Questions tagged [free-energy]

Also known as Gibbs energy, it is the enthalpy minus the product of thermodynamic temperature and entropy.

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### Dependency of Standard Gibbs free energy (using electrode potential) on stoichiometric moles of electron exchanged

I have a question regarding the definition of the number of moles $n$ when using the equation- $$\Delta G=-nF\Delta E$$ I understand that $n$ is the number of moles transferred in the overall redox ...
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### Utility of Delta G

What is the main utility of delta G? As far as I could understand, if we do not know whether the reaction we are dealing with occurs in nature or not, we would not be able to tell in which direction ...
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### Why are Kc and Kp interchangeable in the free energy-equilibrium equation? [duplicate]

In this equation that relates Standard free energy and the equilibrium constant: $\Delta Gº=-RT \ln K_{eq}$ My textbook (and my teacher) say both $K_p$ (constant related to pressure) and $K_c$ (...
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### Active mass,Pressure and concentration

The concentration is connected to the activity via $$a(\ce{A})= \gamma_{c,\ce{A}}\cdot{}\frac{c(\ce{A})}{c^\circ},$$ where the standard concentration is $c^\circ = 1\:\mathrm{mol/L}$. At reasonable ...
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### Which step below is rate determining

What is the rate determining step in the following energy profile? To clarify, the reaction is: A -> B -> C The energy of A is greater than B which in turn is also greater than C. The intermediate A-...
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### Gibbs free energy in chemical reaction

I know this kind of question has been asked many times but I think this is a bit different. We have $G = H - TS$. Here I am talking about chemical reactions at constant pressure and temperature. We ...
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### Which equilibrium constant is appropriate to use?

I have learnt that the standard free energy change is related to the equilibrium constant of a reaction by, $$\Delta G^\circ = -RT \ln K$$ Here, does $K$ refer to $K_p$ or $K_c$? Also, please give ...
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### Predicting the spontaneity of non-isothermal reactions

We use free energy equations -- Helmholtz or Gibbs -- to predict whether or not a reaction is spontaneous. These equations depend on constant temperature. This forum post describes a scenario where ...