# Enthelpy ,gibbs free energy, helmholtz free energy

• abi.ayan
In summary, entropy is a measure of disorder in a system and is related to enthalpy through the equation ΔG = ΔH - TΔS. Gibbs free energy is a measure of available energy in a system and is used to determine spontaneity of a reaction. Entropy can technically be decreased in a closed system, but in an isolated system, it will always increase or remain constant. Helmholtz free energy is used for systems under constant pressure while Gibbs free energy is used for systems under constant pressure and temperature.
abi.ayan
To analyze what does the enthalpy, gibbs free energy and helmholtz free energy are used?What is actually meant by usable energy?

Hello abi. I looked at a few earlier threads from you to place this question in a context. Did not succeed, so I have to ask you: Could you tell us a bit more so we may hopefully provide you with better assistance ?

## 1. What is entropy?

Entropy is a measure of the disorder or randomness of a system. It is a thermodynamic property that increases as the system becomes more disordered.

## 2. How is entropy related to the concept of enthalpy?

Enthalpy is a measure of the total energy in a system, including both its internal energy and the energy required to displace its surroundings. Entropy is related to enthalpy through the equation: ΔG = ΔH - TΔS, where ΔG is the change in Gibbs free energy, ΔH is the change in enthalpy, T is temperature, and ΔS is the change in entropy.

## 3. What is Gibbs free energy and how is it used?

Gibbs free energy is a thermodynamic quantity that measures the amount of energy available to do work in a system. It takes into account both the enthalpy and entropy of a system. It is often used to determine whether a chemical reaction will occur spontaneously, with a negative ΔG indicating a spontaneous reaction.

## 4. Can entropy be decreased?

Entropy can technically be decreased in a closed system, but it would require an external energy input and would result in a decrease in the system's enthalpy. In an isolated system, entropy will always increase or remain constant.

## 5. What is the difference between Helmholtz free energy and Gibbs free energy?

Helmholtz free energy is a thermodynamic quantity that measures the amount of energy available to do work at a constant temperature and volume. It is used for systems that are under constant pressure, while Gibbs free energy is used for systems that are under constant pressure and temperature. In other words, Gibbs free energy takes into account both temperature and pressure, while Helmholtz free energy only takes into account temperature.

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