## Gibbs free energy

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

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

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

josephyim1L
Posts: 61
Joined: Fri Sep 28, 2018 12:15 am

### Gibbs free energy

Can someone explain the difference between Gibbs free energy and enthalpy/entropy/heat?

Jonathan Omens 1K
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

### Re: Gibbs free energy

Gibbs free energy is a measure of energy contained within a system. More specifically, this energy is the energy in the system that can be accessed to do work.

Enthalpy is the measure of energy due to temperature.

Entropy is a measure of the number of quantum states that a system can occupy.

Heat is a transfer of thermal energy.

Nathan Tran 4K
Posts: 92
Joined: Fri Sep 28, 2018 12:16 am

### Re: Gibbs free energy

In terms of the equations, gibbs' free energy sees a relationship with enthalpy and entropy where delta G = Delta H - T * Delta. Heat is a measurement of how much energy is transferred, but in terms of energy that is not able to do work, whereas Gibbs free energy is a measurement of how much work something can do. Also, heat equals change in enthalpy under constant pressure conditions.

Posts: 60
Joined: Fri Sep 28, 2018 12:27 am

### Re: Gibbs free energy

Gibbs free energy is not measured directly (like enthalpy is by a calorimeter). Rather, it is a calculated value that we get when we know enthalpy, entropy, and temperature.

JacobHershenhouse3G
Posts: 32
Joined: Thu Jan 10, 2019 12:17 am

### Re: Gibbs free energy

You can think about Gibbs free energy as a conglomeration of enthalpy, temperature, and entropy because they are all related to energy and the amount of work a system can do, so the GFE equation brings them all together. Hope this helps :)

Yiting_Gong_4L
Posts: 69
Joined: Fri Sep 28, 2018 12:25 am

### Re: Gibbs free energy

Gibbs free energy is the energy that is available to do work, unlike entropy/enthalpy/temperature, it cannot be directly measured.

Niveda_B_3I
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Re: Gibbs free energy

Gibbs free energy is the amount of energy that is available to do work, and the equation shows the relationship between entropy and enthalpy as well.

Cody Do 2F
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

### Re: Gibbs free energy

Gibbs Free Energy is a concept developed to explain the energy within a system that is readily available to do work. It can't be directly measured and thus must be ascertained through calculations. When discussing the change in Gibbs Free Energy, we can say that if the value is negative, then the reaction is spontaneous at X pressure and Y temperature and if it's positive, then the reaction is not spontaneous at X pressure and Y temperature.

Return to “Gibbs Free Energy Concepts and Calculations”

### Who is online

Users browsing this forum: No registered users and 1 guest