## Gibbs

$\Delta G^{\circ} = -nFE_{cell}^{\circ}$

CHEM 14B Lover
Posts: 33
Joined: Fri Sep 28, 2018 12:19 am

### Gibbs

Could someone explain to me in words (to help me conceptualise) what Gibbs Free energy is?

Parth Mungra
Posts: 72
Joined: Fri Sep 28, 2018 12:28 am

### Re: Gibbs

Gibbs Free energy helps us calculate the energy that is free to do work after a certain process. This does not include the energy in between electrons or protons, but it is the energy that can be transferred to do, for example, expansion against a force.

Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Re: Gibbs

It is the energy available to do work, which determines spontaneity of a reaction because a negative value of delta G means the reaction is spontaneous, while a positive value means it is not spontaneous.

Jennifer Su 2L
Posts: 47
Joined: Wed Nov 21, 2018 12:20 am

### Re: Gibbs

Gibb's Free Energy can be calculated through using enthalpy and entropy.
deltaG=deltaH - T*deltaS

When a reaction has a positive enthalpy (+deltaH):
deltaG will be positive if entropy is negative (-deltaS)
deltaG will be negative if entropy is positive (+delta S) and T*deltaS is greater than deltaH

When a reaction has a negative enthalpy (-deltaH):
deltaG will be positive if entropy is negative (-deltaS) and T*deltaS is greater than deltaH
deltaG will be negative if entropy is positive (+deltaS)

When a reaction has a positive deltaG, then it is not spontaneous because it means the products has more free energy than the reactants (an input of free energy is needed).
When a reaction has a negative deltaG, then it is spontaneous because it means the products has less free energy than the reactants (free energy is released).

Return to “Work, Gibbs Free Energy, Cell (Redox) Potentials”

### Who is online

Users browsing this forum: No registered users and 1 guest