All Questions
Tagged with free-energy kinetics
9
questions
1
vote
0
answers
51
views
Define a rate-determining step and an energy barrier for a multi-step reaction profile
I am currently making reaction profile by means of DFT calculations. I am able to correctly draw a whole reaction profile.
However, I am struggling to find what exactly is the energy barrier of a ...
- 398
11
votes
2
answers
3k
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True or false: "If a reaction has a large negative value of ∆G, then it will be a fast reaction."
I recently took a Gen. Chem. 2 exam that contained this question. I answered false, as I knew that thermodynamics and kinetics are separate matters. My professor said the answer is true. I pressed him ...
- 449
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
4
votes
2
answers
6k
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Which step below is rate determining
What is the rate determining step in the following energy profile? To clarify, the reaction is:
A -> B -> C
The energy of A is greater than B which in turn is also greater than C. The intermediate A-...
- 177
1
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1
answer
1k
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Relative energies between reactants and products
I've been asked to draw a relative energy sketch of the reactants and the two products. The reaction being examined was adding copper acetate monohydrate to glycine in two different fashions to create ...
- 11
3
votes
2
answers
15k
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What is the correct definition of the Gibbs free energy of activation?
Is the following correct?
Gibbs free energy of activation is used in energy profiles where the stabilities of the species are expressed as changes in Gibbs energy, while the activation energy Ea is ...
- 14.4k
5
votes
3
answers
2k
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Rate-limiting in transition state theory
Suppose an initial state $A$ can transition to either state $C$ or state $D$. Suppose further that both of these two processes are rate-limited by a transition to the same intermediate state $B$, as ...
- 401
5
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3
answers
8k
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Activated Complex Products/Reactants
We know that an activation complex is the temporary unstable compound formed when activation energy is reached. But what dictates whether the products are indeed going to be products or if they become ...
- 972