Questions tagged [free-energy]
Also known as Gibbs energy, it is the enthalpy minus the product of thermodynamic temperature and entropy.
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Why is the reverse aldol cleavage of fructose 1,6-bisphosphate highly endergonic under standard conditions?
I have another question similar to this one. I just don't have intuition for why reactions are thermodynamically favorable or unfavorable and I'd like to build it. This time I'd like to ask about ...
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Is the formation of nitrogen dioxide spontaneous?
I was studying Thermodynamics from my Chemistry textbook (page 181-182, section 6.6 (a)).
I have a question regarding the following text from my book.
Now let us examine the following reactions:
$$\...
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Is a change in delta-delta-G typically notated as delta-delta-delta-G?
I'm currently writing a research paper, and need to refer to a difference between $\Delta{\Delta}G$s. The naive way to notate this would be $\Delta{\Delta}{\Delta}G$, but that looks cumbersome and ...
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Is it possible to estimate the abundance of conformers from J values?
I have a system of two disubstituted cyclohexanes and I want to estimate the abundance/ratio of the two based on the J values and if possible, roughly estimate the difference in free energy.
To get ...
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How to find Gibbs energy for a real gas
I'm asked to find $\Delta G$ for the isothermal compression of $\ce{N2(g)}$ (real gas) at $0\ \mathrm{^\circ C}$ if the gas expands from $P=1\space\mathrm{atm}$ to $P=1000 \space\mathrm{atm}$. The ...
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Is the change ΔG for an ideal gas unknown?
When one is introduced to the first law of thermodynamics, one learns that enthalpy is only a function of temperature, and calculating its changes is straightforward
\begin{equation}
\Delta H^\pu{...
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Gibbs free energy of mixing in a control volume
I'm trying to model the amount of energy lost due to mixing of a $\mathrm{HCl}$ solution using the Gibbs free energy of mixing. However, I really like a second opinion on the model and the results, ...
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Why does standard reduction potential get multiplied by the change in oxidation state and not by the number of electrons transferred?
The whole basis of Frost diagrams is to have a graphical representation of the Gibbs free energy of formation ($\Delta{G}_{f}$) of different oxidation states of an element using the proportional ...
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Thermodynamics: Solving for Entropy, Gibbs and Helmholtz
A reversible melting of $32.0\ \mathrm g$ of ice at $0\ \mathrm{^\circ C}$ and $1\ \mathrm{atm}$. Solve for $\Delta G, \Delta S_\text{universe}$, and $\Delta A$
I'm also given latent heat of fusion/...
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Gibbs Free Energy - Maximum Work
I've been having a lot of trouble trying to truly understand Gibbs free energy from a practical perspective. I have no background in physical chemistry, but I think I have a firm grasp on many of the ...
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Gibbs energy of electron transfer
The reaction Gibbs free energy of a cell is
$\Delta_\mathrm{r}G^\circ = -nFE^\circ, \tag{1}$
and the Gibbs energy of photoinduced electron transfer according to IUPAC is
$$\Delta_\mathrm{ET}G^\circ = ...
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How much energy water "captures" at it evaporates in room temperature?
As explained in Why does water evaporate spontaneously at room temperature despite ΔG > 0? water evaporates in room temperature because partial pressure of water is less than "standard" conditions ...
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NAMD free energy calculations (FEP, Alchemical)
I am trying to calculate the absolute free energy of a protein-ligand-complex using the free energy perturbation theory.
Following the alchemical route in this tutorial, I have calculated eight MD-...
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reconciling free energy equations
I am struggling with a very basic concept and I think the issue lies in the definition of standard states.
When calculating standard state free energy change via Gibbs equation $$\Delta G^ \circ = \...
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Active mass,Pressure and concentration
The concentration is connected to the activity via
$$a(\ce{A})= \gamma_{c,\ce{A}}\cdot{}\frac{c(\ce{A})}{c^\circ},$$
where the standard concentration is $c^\circ = 1\:\mathrm{mol/L}$. At reasonable ...
