Talk:Proton affinity
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Untitled
edit"The strongest known base is the methanide anion (Epa = 1743 kJ/mol)" - I don't think this is right. Just a quick search turned up the following paper which gives SO42- with 1847 kJ/mol. "Proton affinities of sulfate and bisulfate ions", J. House and K. Kemper, Journal of Thermal Analysis, 1987, 32, 6, 1855-1858, DOI:10.1007/BF01913977 I think the quoted statement is based on looking at one source, and assuming that has the highest proton affinity known, which is not the case. —Preceding unsigned comment added by 212.87.14.5 (talk) 13:30, 2 March 2010 (UTC)
Energy
editThe use of the term "energy" is unhelpful. I presume that what is meant is enthalpy not free energy. It is also unclear that the "energy" is temperature dependent, as both enthalpy and free energy are. Petergans (talk) 18:55, 21 April 2010 (UTC)
Hydration Energy of Base
editThe hydration energy of F−(g) → F−(aq) given in the article (-13 kJ/mol) seems to be too small. In other sources values between -457 kJ/mol (ChemFactSheet, 94 "Enthalpies of Solution") and -524 kJ/mol (Dasent, p. 152; D.W. Smith, J. Chem. Educ., 54, 540 (1977)) are given.
reverse sign convention of PA
editThe article says "a positive Epa indicating an intake of energy by the system" but it should be the other way around in my opinion. A positive PA means the reaction is exothermic and therefore, the system reaches a lower energy level. Energy is leaving the system. — Preceding unsigned comment added by 129.132.232.117 (talk) 17:03, 18 October 2012 (UTC)
Assessment comment
editThe comment(s) below were originally left at Talk:Proton affinity/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
| The nomenclature is fuzzy (energy - enthalpy - Gibbs energy are mixed).
Values must be updated, as well as the bibliography. Almost nothing about neutral bases (except Helium...) JF Gal gal@unice.fr |
Last edited at 15:21, 12 March 2008 (UTC). Substituted at 03:30, 30 April 2016 (UTC)
Opening sentence
editThe opening sentence of this article is not gramatically correct - "The proton affinity (PA, Epa) of an anion is a neutral atom or molecule is the negative of the enthalpy change in the reaction between above species and proton in the gas phase
PeterClarke 14:14, 8 November 2020 (UTC)
- I agree; the sentence doesn't make any sense anymore. The most recent edit of the page made by PiratePuppy should be reverted, or the user made know of the issue so it can be corrected. From the edit alone it is impossible to determine what the user actually meant to write or say.
- Jonathan-rb (talk) 00:16, 10 March 2021 (UTC)
Incorrect values
editAs I was using this page to look up the definition, we noticed with my colleague that some of the numbers are wrong. Apparently, the value for H+(q) -> H+(aq) is around 270 kcal/mol or around 1150 kJ/mol.[1][2][3] The given value, -1530 kJ/mol, seems to be heat of formation.[4][5][6] I am not sure about the other numbers, some seem to be correct (HF(g) -> HF(aq), for example[7]). I am marking this as needing more sources and checking, because it does not seem to be doing a correct calculation. KingisNitro (talk) 15:14, 2 May 2022 (UTC)
References
- ^ Mejı́as, J. A.; Lago, S. (2000-11-01). "Calculation of the absolute hydration enthalpy and free energy of H+ and OH−". The Journal of Chemical Physics. 113 (17): 7306–7316. doi:10.1063/1.1313793. ISSN 0021-9606.
- ^ Tissandier, Michael D.; Cowen, Kenneth A.; Feng, Wan Yong; Gundlach, Ellen; Cohen, Michael H.; Earhart, Alan D.; Coe, James V.; Tuttle, Thomas R. (1998-10-01). "The Proton's Absolute Aqueous Enthalpy and Gibbs Free Energy of Solvation from Cluster-Ion Solvation Data". The Journal of Physical Chemistry A. 102 (40): 7787–7794. doi:10.1021/jp982638r. ISSN 1089-5639.
- ^ Pollard, Travis P.; Beck, Thomas L. (2014-11-14). "The thermodynamics of proton hydration and the electrochemical surface potential of water". The Journal of Chemical Physics. 141 (18): 18C512. doi:10.1063/1.4896217. ISSN 0021-9606.
- ^ "Chemical Ionization - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-05-02.
- ^ Roux, M. V.; Jiménez, P.; Dávalos, J. Z.; Castaño, O.; Molina, M. T.; Notario, R.; Herreros, M.; Abboud, J.-L. M. (1996-01-01). "The First Direct Experimental Determination of Strain in Neutral and Protonated 2-Azetidinone". Journal of the American Chemical Society. 118 (50): 12735–12737. doi:10.1021/ja962792w. ISSN 0002-7863.
- ^ "Gas-Phase Ion Thermochemistry". webbook.nist.gov. Retrieved 2022-05-02.
- ^ Bartmess, John E.; Scott, Judith A.; McIver, Robert T. (1979-09). "Scale of acidities in the gas phase from methanol to phenol". Journal of the American Chemical Society. 101 (20): 6046–6056. doi:10.1021/ja00514a030. ISSN 0002-7863.
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