Decomposition potential and Gibbs Free Energy

In summary: Hmm but isn't it counter intuitive? Since in a normal cell the higher the E the more negative delta G is. But in this case it seems like the higher the E the more positive the delta G should be. Why is this so?The thermodynamic potentials are only for systems that are in equilibrium. In reality, systems never behave in equilibrium, and the overpotential is always higher than the theoretically determined potential.
  • #1
sgstudent
739
3
The decomposition potential is always higher than the theoretically determined potential by thermodynamics. E=η+Eeq where E is the decomposition potential, η is the overpotential and Eeq is the theoretically determined potential.

And ΔG=-nFE and if we were to substitute the decomposition potential into this equation, the higher the decomposition potential the more negative the Gibbs Free Energy. This seems wrong because intuitively I feel like the higher the decomposition potential the more energy is required. Like in any electrical appliance the greater the voltage the more energy is needed. So what is wrong with my concept here?
 
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  • #2
Overpotential covers loses, not the original process.
 
  • #3
Borek said:
Overpotential covers loses, not the original process.
So should the equation be E=Eeq-η instead? But still why would the decomposition potential for the process be higher than what was thermodynamically determined E? And how would I calculate the delta G this way?
 
  • #4
sgstudent said:
why would the decomposition potential for the process be higher than what was thermodynamically determined E?

Because the thermodynamical values are for a process that goes infinitely slow through a series of equilibrium positions. No real system behaves this way.

This is not different conceptually from the way Carnot cycle describes heat engine. It gives a theoretical estimation of the maximum efficiency, but no system ever will be able to reach it.
 
  • #5
Borek said:
Because the thermodynamical values are for a process that goes infinitely slow through a series of equilibrium positions. No real system behaves this way.

This is not different conceptually from the way Carnot cycle describes heat engine. It gives a theoretical estimation of the maximum efficiency, but no system ever will be able to reach it.

Hmm but isn't it counter intuitive? Since in a normal cell the higher the E the more negative delta G is. But in this case it seems like the higher the E the more positive the delta G should be. Why is this so?
 

What is decomposition potential?

Decomposition potential is the minimum amount of energy required to break down a compound into its constituent elements. It is also known as the thermodynamic potential for decomposition.

What is Gibbs Free Energy?

Gibbs Free Energy is a measure of the maximum amount of work that can be extracted from a thermodynamic system at a constant temperature and pressure. It is represented by the symbol G and is defined as the difference between the enthalpy and the product of the temperature and entropy of the system.

How are decomposition potential and Gibbs Free Energy related?

The decomposition potential of a compound is directly related to the Gibbs Free Energy of the reaction. As the decomposition potential increases, the Gibbs Free Energy of the reaction also increases, indicating that more energy is required to break down the compound.

What factors influence the decomposition potential and Gibbs Free Energy of a compound?

The decomposition potential and Gibbs Free Energy of a compound are influenced by factors such as temperature, pressure, and the chemical composition of the compound. Higher temperatures and pressures can increase the decomposition potential and Gibbs Free Energy, while the presence of more stable bonds can decrease these values.

Why are decomposition potential and Gibbs Free Energy important in chemical reactions?

Decomposition potential and Gibbs Free Energy are important in chemical reactions because they provide information about the stability and feasibility of a reaction. A negative Gibbs Free Energy indicates that a reaction is spontaneous and will proceed without the input of external energy, while a positive value indicates that the reaction is non-spontaneous and will require energy to proceed.

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