Talk:Activation energy

message: The article does not supply enough information about how the activation energy breaks the first bonds in a reactant (or similar, i forget the correct term) and how this then continues the reaction. Instead the article talks more theoretically how the Activation Energy is a point where the needed energy is supplied and the reaction continues.
Although I'm just a student learning about this, I beleive that more information about chemical bonds etc would be good. If I'm wrong or confusing all this with something else then forget it. Thanks!
84.92.204.165 16:33, 14 January 2007 (UTC)
thread_title: Bond information needed?

message: In the first paragraph, this sentence:
:This requires energy - activation energy - and comes from the heat of the system i.e., the translational, vibrational etc... energy of each molecule.
contains an "etc..." that I don't think is needed. First of all, "etc." and "..." is redundant (both mean "and so on"). Secondly, the heat is contained in the translations, vibrations, and rotations of the molecules.  Couldn't the "etc." be replaced by "and rotational" without any loss of explanatory power. At room temperature, other degrees of freedom (such as electronic and nuclear transitions) make a negligible contribution to the heat capacity. So unless anyone objects, could the sentence instead read:
:This requires energy - activation energy - and comes from the heat of the system, i.e. the translational, vibrational, and rotational energy of each molecule.
::Hmm.  Actually, that's wrong.  There are a number of reactions where the activation energy is not supplied by heat.  Specifically, there are electrochemcial reactions and photochemical reactions where the activation energy comes from electric fields or incident photons.  Rare, sure, but certinally important.  I'll edit the article to point out these cases. Syntax 15:03, 9 December 2005 (UTC)
thread_title: "Etc" needed?

message: The article refers to Figure 1 but there doesn't appear to be a figure 1. Was this text copied from somewhere? Perhaps it needs rewriting to remove the reference, but better if a figure 1 could be sourced and supplied showing a typical transition state energy plot? ++Lar: t/c 16:55, 1 January 2006 (UTC)
thread_title:  Figure 1 

message: I've taken a lot of material out of this page.  It wasn't vandalism (despite lots of people trying to revert me!)  The info was simply wrong, or, at best, of limited relevance or misleading.
And I've taken the technical flag off.
129.16.97.227 (talk) 15:53, 11 December 2007 (UTC)
thread_title:  Removed a lot of material 

message: *"Die Gesteinsproben sollen unter anderem auf rund 1000 Grad Celsius erhitzt werden, um Aufschluss über den Wassergehalt und die in der Probe enthaltenen Minerale zu erhalten. 
Die Forscher suchen insbesondere nach Spuren von Kohlenstoff, Wasserstoff und Stickstoff."
*http://www.sueddeutsche.de/wissen/artikel/410/179858/
*http://de.wikipedia.org/wiki/Thermogravimetrie
*http://de.wikipedia.org/wiki/Mikrowaage
*http://de.wikipedia.org/wiki/Aktivierungsenergie
: Der Mars besteht zu 95,3 % aus CO2
*http://de.wikipedia.org/wiki/Mars_%28Planet%29
194.66.226.95 (talk) 12:02, 12 June 2008 (UTC)
thread_title: Aktivierungsenergie: Die Chemische Darstellung von Kleinsten Millimeter Planetenbodens 

message: I really feel that it would be more correct to say that the catalyst provides for an energetically more favorable pathway. Rather than just to say it lowers the activation energy. The activation energy is the difference between the energy  at  the initial state and the energy of the transition state. So, a catalyst would therefore induce, in a sense, an alternative transition state that is lower in energy than the original transition state. Consequently, it would provide for a more energetically favorable reaction path. Its presence does not lower the energy of the transition state, but rather it participates in the formation of an alternate transition state that has a lower energy. This is admittedly nit-picky however.The Lamb of God (talk) 02:52, 5 December 2009 (UTC)
thread_title:  catalysis 

message: Quote: "The blue flame will sustain itself after the sparks are extinguished because the continued combustion of the flame is now energetically favorable."
"Energetically favorable"? - Isn't it simply because the constant stream of incoming volatile gas runs into already burning gas...
:At the higher temperature it is favorable where at the lower temperature it is not. Favorable refers to a formula (a mathematical inequality). What you say is true, but omits the reference to a numerical test. 
:Actually, I see that there is an ambiguity. "Energetically favorable" could refer either to thermodynamically favorable, or to the reaction rate (kinetics). Thermodynamically favorable means the sign of the Gibbs free energy difference of the two end states, which changes with temperature. The reaction rate depends on the supply of energetic particles, which increases at higher temperature, as well as the activation energy, which I'm reading this article to find out about. So both of these kinds of "favorable" can change with temperature. But I don't know which effect dominates in common situations.
:178.38.83.75 (talk) 17:43, 3 April 2015 (UTC)
thread_title:  Explanation under the first picture (with sparks and flame) 

message: Substituted at 06:38, 29 April 2016 (UTC)
thread_title: Assessment comment

message: In physicshttps://www.tandfonline.com/doi/abs/10.1080/00150193.2012.707592, materials science,https://onlinelibrary.wiley.com/doi/full/10.1111/j.1151-2916.1990.tb05175.x and nuclear sciencehttp://www.physics.ohio-state.edu/~kagan/phy367/Lectures/P367_lec_14.html there are significant uses of the phrase "activation energy" each of which have a similar physical meaning as is used for the chemical reaction application. I believe that this page should be significantly modified to reflect these changes.  — Preceding unsigned comment added by Antwan718 (talk • contribs) 01:21, 22 May 2018 (UTC)
thread_title: Generalization of Activation Energy

message: I have added a small concluded blurb at the bottom of this section to wrap things up. This blurb is meant to affirm activation's energy relation to overall reaction energy - them being independent of each other. Perhaps the wording can be altered slightly, though I think this piece wraps up the section nicely in understanding activation energy's role in a whole process.RockstheBlugold (talk) 22:37, 22 November 2019 (UTC)
thread_title:  Section - "Relationship with Gibbs Energy of Activation" 

message: The entropy and enthalpy of activation are typically the standard enthalpy of activation and standard entropy of activation.  The standard state symbol should also be there. This is not actually just a question of semantics, it is a common misconception that the tabulated values are free from standard states. Usually they are not free from standard states. http://goldbook.iupac.org/terms/view/E02142  — Preceding unsigned comment added by Ashi Starshade (talk • contribs) 21:52, 3 May 2020 (UTC)
thread_title: Standard States

message: See commits: Special:Diff/1000520950, Special:Diff/1182119303
I'm removing this section. Potential energy surfaces enable the estimation of activation enthalpy/entropy in transition state theory, the successor to the Arrhenius theory of reaction rates. The transition state theory article already includes a short discussion of the connection (PES saddle point energy determines enthalpy); it's less relevant to this article.
Moreover, this section appears to be an edited copy of the Fig. 3 images and text in 
It includes several errors which suggest the wiki author may not be one of the paper authors, contrary to the copyright statement in :File:Comparative_between_1D_and_2D_PES_for_tungsten_and_hydrogen_gas_reaction.jpg:
* The 2D PES maps the energy of hydrogen adatoms (relative to gas-phase H_2) bound to a W(110) surface - it's not a PES for the surface binding/dissociation of H_2.
* Likewise, the 1D reaction coordinate diagram is for the minimum-energy path of hydrogen adatoms between W(110) surface binding sites, not for "the reaction of hydrogen gas and tungsten".
* The non-word "depics" in the sentence "The depics correspond to the trajectories" appears to be a misphrasing of the paper's sentence beginning "Fig. 3 depicts that the trajectories corresponding to the one Cu has, have somewhat symmetrical shape".
So even if we conclude that a section on potential energy surfaces is appropriate in this article, I think we'll have to write one from scratch, rather than reworking this one. Preimage (talk) 07:16, 27 October 2023 (UTC)
replies: text: . I don't understand any of that, but I just want to say that I appreciate you using your subject matter expertise to improve the encyclopedia. I support your efforts and I hope you stick around! Happy editing :) –Novem Linguae (talk) 08:14, 27 October 2023 (UTC)
thread_title:  Activation energy in a 2D potential energy surface