pKa Conceptual Questions [closed]








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If anyone could clear up some of this conceptual confusion, that would be much appreciated.


1. Is $\mathrm pK\_\mathrm a$ an intrinsic property of a molecule? Or extrinsic? A property is extrinsic if it depends on the environment (e.g. weight), and intrinsic if it is independent of the environment (density). Source: [Thoughtco: Intrinsic Property Def](https://www.thoughtco.com/definition-of-intrinsic-property-605256).
2. Doesn't $\mathrm pK\_\mathrm a$ change according to environment/conditions the molecule is in? According to the definition, $\mathrm K\_a = [\ce{H^+}][\ce{A^-}]/[\ce{HA}]$. Then, given a [$\mathrm pK\_\mathrm a$ table](http://evans.rc.fas.harvard.edu/pdf/evans_pKa_table.pdf), what are all the $\mathrm pK\_\mathrm a$ values calculated with reference to? What are the standard conditions in which scientists calculate their $\mathrm pK\_\mathrm a$ values.
3. Is there a way to calculate $\mathrm pK\_\mathrm a$ from known intrinsic properties of a molecule? E.g. if I give you one molecule of a compound, and only one molecule, is it possible to calculate $pK\_a$ based off the intrinsic structure of that molecule, given no other information?


