# Questions tagged [entropy]

For questions about the thermodynamical state function entropy, commonly understood as a measure of disorder.

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### Computation of thermodynamic functions of molecules by molecular parameters

I want to implement in my program Chemcraft the computation of entropy and Gibbs energy of molecules in approximation "rigid rotor - harmonic oscillator", by the molecular parameters (...
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### If the same reaction happens at two different pressures… will the entropy change be the same [closed]

This is the question I was solving where I encountered this problem. They have assumed it to be so to arrive at the answer]1
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### Determine enthalpy and entropy from measurements of Kd at different temperatures?

In biochemical experiments, it is very common to measure IC50 (half inhibitory concentration) eg by adding different amounts of an inhibitor to an enzyme+substrate and measuring the reaction rate or ...
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### Can we interpret the number of micro states calculated from molar entropy?

Forgive me if this is not the correct place to ask this. When I encounter a molar entropy, is it possible to rearrange the Boltzmann entropy formula $$S=k\log W$$ and meaningfully interpret the number ...
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### How are fundamental equations valid for both reversible and irreversible processes?

We know for an irreversible process, $\mathrm dS\gt\mathrm dq/T$. And if the process is done at constant pressure we can take the equation as $\mathrm dH-T\,\mathrm dS\lt0$. And we defined Gibbs ...
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### Can Vdp work be considered irreversible work (e.g., production of entropy)?

Since conduction across a finite temperature difference will produce entropy, will work done due to pressure difference generates entropy because system tends towards mechanical equilibrium which ...
1 vote
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### If entropy is a state function, how can it be calculated for both reversible and irreversible processes?

$$\Delta S = nR\ln( V_2/V_1)$$ The value of ΔS of the system is independent of the path between the initial and final states, so this expression applies whether the change of state occurs reversibly ...
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### Isn't the change in Gibbs free energy for a reversible process zero?

In problem 6, part 6.5 of the 2020 IChO (PDF), a thermodynamic cycle is given for “one mole of monoatomic perfect gas”: $\mathrm{A \to B}$; isothermal reversible expansion receiving $\pu{250 J}$ by ...
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1 vote
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### Justifying assumptions about method to find equilibrium pressure for co-existence of graphite and diamond

The standard state Gibbs free energies of formation of $\ce{C(graphite)}$ and $\ce{C(diamond)}$ at $T = \pu{298 K}$ are $\pu{0 kJ mol-1}$ and $\pu{2.9 kJ mol-1}$, respectively. The conversion of ...
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### What does the change in Gibbs Free Energy refer to?

Usually change is indicated as the difference between some initial and final state. However, for ΔG there seem to be multiple definitions and I am a bit confused. For example, at equilibrium, ΔG = 0 ...
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### Change in entropy in reversible and irreversible processes

The change in entropy for a reversible process is given as- $\Delta$S = $\frac{q_{rev}}{T}$ Where qrev is the heat supplied isothermally and reversibly. The change in entropy for a irreversible ...
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### Where is my non-expansive work in combustion?

Consider if I burn some octane. The enthalpy released is $5430 \;\text{kJ/mol}$. The Gibbs free energy released is $5537 \;\text{kJ/mol}$. From my understanding, enthalpy is the heat change in the ...
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### Does entropy contribute work?

I've seen that Gibbs free energy is defined as the maximum amount of work that a system can do. From this I gather, this is how much energy it will release - right? But, I've also learnt that the heat ...
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