# Questions tagged [entropy]

An important extensive property of all systems in thermodynamics, statistical mechanics, and information theory, quantifying their disorder (randomness), i.e., our lack of information about them. It characterizes the degree to which the energy of the system is *not* available to do useful work.

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### Thermodynamic entropy vs statistical mechanical entropy

In thermodynamics, we define the change in entropy of a system as: where $T_b$ is the temperature at the boundary of the system. But in statistical mechanics, we define the change in entropy of a ...
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### Will the calculated mathematical probability of a decrease of disorder in mixing of gases violate the second law of thermodynamics?

I have read that two different gases mix together when the separation between their chambers is open so as to increase entropy.Similarly the mixed gases won't separate by itself so as to not decrease ...
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### Using quasistatic processes to calculate quantities

This question is inspired by Reif Problem 5.5. Note that it is not a homework problem and, even if it were, my question only loosely relates to it. A vertical cylinder contains $N$ molecules of a ...
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### What is the meaning of mutual quantum information?

I'm having some difficulty understanding the physical meaning of the mutual information that two subsystems share with each other. For example, if $\rho_{AB}$ defines the matrix of a bipartite state, ...
1 vote
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### How do I calculate enthalpy and entropy from Gibbs energy? [closed]

If for a system the Gibbs energy depends on the temperature like this: $$G(T) = aT + b + c/T$$, how would enthalpy and entropy depend on temperature?
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### Boltzmann vs Gibbs definition of entropy [duplicate]

I am learning Statistical Mechanics and I have a question regarding different definitions of (statistical) entropy. If we use Boltzmann's definition: $$\sigma \propto\ln(W)$$ Where $\sigma$ is the ...
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### What are the applications of materials if their entropy increases with temperature? [closed]

What could be the possible applications of the materials if their entropy increases with increasing temperature.