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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Relationship between Enthalpy and Gibbs energy [duplicate]
I am a little stuck understanding the difference between Gibbs free energy and enthalpy. Both are measured in Joules and hence some sort of energy.
In a chemical reaction where C --> A + B
If A and ...
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Why is the formation of a peptide bond not spontaneous?
Why is the formation of a peptide bond from a carboxylic acid and amine not spontaneous?
I'm not looking for the free energy calculation; I have it from several sources. I'm just asking for an ...
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Ordered and random energy [closed]
One of the books refer to potential energy being ordered whereas heat energy being random. Could someone explain what is ordered and random energy?
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Entropy and Gibbs Free Energy of Chelate Complexes
Of [Cd(NH2CH3)4]2+ and [Cd(en)2]2+ the stability of the latter is higher than the former attributing to chelation in the en complex .This is evident from the fact that the Gibbs Free Energy change for ...
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Is it possible to measure the entropy of a chemical reaction through calorimetry?
My broad question is how do you measure entropy change? I was doing a bit of digging into how thermodynamic tables are developed at I got this from NIST. Basically it seems like you need to indirectly ...
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Gibbs free energy for the evaporation of water
Problem
Find the value of $\Delta G$ for the evaporation of water at $\pu{100 °C}$ and $\pu{1 atm}.$
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I have the following data:
$$
\begin{array}{lcc}
\hline
\text{Compound} & \...
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How to use anodic and cathodic overpotentials to calculate electrolytic energy efficiency?
I am trying to calculate the energy efficiency for $\ce{CO2}$ reduction to formate, coupled to water oxidation based on literature data.
$$\ce{CO2 + 2e- + 2H+ -> HCOOH}$$
$$\ce{H2O -> 2H+ + 1/...
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Reactions with a positive Delta H and a negative Delta S are said to be nonspontaneous at ALL temperatures. But what if the temperature IS low enough? [closed]
What I mean is, that if you use G = H-TS and make the temperature low enough, couldn't you make any reaction spontaneous? For example, you have a Delta H of 85 kJ and a Delta S of -66 J/K. I've been ...
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What would be the physical interpretation of the equation dG = Vdp − SdT?
I was trying to understand the derivation of the formula $G=G^\circ+RT\ln (p/p^\circ)$ starting with the following relationships:
$$
\begin{align}
\mathrm dU&=T\,\mathrm dS-p\,\mathrm dV\tag{1}\\
\...
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Isobaric entropy relation from isothermal Gibbs free energy relation
I have been given a problem to derive a relation for change in entropy from change in Gibbs free energy:
Starting with the isothermal equation
$$G(p_2) = G(p_1) + nRT\ln\frac{p_2}{p_1}\label{eqn:1}\...
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Can endergonic reactions be driven by heat?
I am having trouble conceptualizing endergonic reactions and their difference from endothermic reactions. An endergonic reaction is one that has a positive Gibbs free energy change, such that energy ...
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Derivation and visualization of cell potential dependency on temperature and entropy
Working from the thermodynamic identity
$$\Delta{S} = -\left(\frac{\partial{\Delta{G}}}{\partial{T}}\right)_p,$$
is it allowed to integrate both sides to obtain an expression derived from the Nernst ...
user85551
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Change in enthalpy and entropy when sugar dissolves in water
We know that dissolution of sugar in water is a spontaneous process.
So, change in Gibbs free energy $(ΔG)$ must be negative for the overall process:
$$ΔG = ΔH - TΔS < 0$$
Hence either the enthalpy ...
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Finding Gibbs energy at different temperatures just given Gibbs energy at one temperature
How would it be found the Gibbs energy at a certain temperature, if they just give you another Gibbs energy at a temperature? For example: Given $\Delta G = -230 Kcal/mol$ at $773K$ for the reaction $...
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