All Questions
Tagged with free-energy transition-state-theory
7
questions
4
votes
2
answers
1k
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How to estimate the temperature needed to overcome an activation energy barrier?
Trying to elucidate a reaction pathway, I calculated the energies for different transition states possible for that reaction (computational chem. DFT). I found activation free energies ranging from 29 ...
3
votes
1
answer
567
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Can rate constant depend upon the concentration of reactants (or other species involved in the reaction)?
Transition state theory tells us that the rate constant of an elementary step is $$k_\mathrm{r} = \frac{\kappa k_\mathrm{B}T}{h}\exp\left\{\frac{- \Delta G^\ddagger}{RT}\right\},$$
where $\Delta G^\...
- 5,685
2
votes
1
answer
281
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Is Gibbs Free Energy of formation equal to Gibbs Free Energy of transition state?
Is activation energy equivalent to Gibbs Free Energy of transition state as related by Eyring equation?
$$E_a=\Delta ^\ddagger G \, \, ?$$
Is Gibbs Free Energy of transition state defined by the ...
- 43
9
votes
1
answer
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Entropy of Activation and Temperature Dependence
I am trying to understand the extrapolation of enthalpy $\Delta H^{\ddagger}$ and entropy of activation $\Delta S^{\ddagger}$ from the Eyring equation. It's typically cast as:
$$\ln\left(\frac{k}{T}\...
2
votes
1
answer
474
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If Gibbs energy of activation is positive, how is the change to the transition state possible?
The Gibbs energy increases from the reactants to the transition state, but according to the Second Law of Thermodynamics, entropy of the universe can only increase. Why is the transition state ...
- 2,725
4
votes
1
answer
140
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How is the energy of reactants in a chemical reaction found ?
A pretty rudimentary question, but I'm reviewing the concept of energy diagrams and activation energy and I'm curious to know how chemists find the energy of reactants and of a transition state in a ...
- 155
14
votes
3
answers
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Transition state and free energy
We have products $\ce{A + B}$ combining to form $\ce{C + D}$ through the transition state $\ce{X}$.
Are all reactions at least virtually reversible? Is the difference between a reversible reaction ...
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