I wondered if it was possible to predict the product(s) of a reaction (or even the equilibrium) based on the reactants and the temperature/pressure.

I found an answer to a similar question here:

No, there is no such thing as chemical reaction are not that easily predictable. You can get result right in some cases, but it is impossible to count all factors.

What (significant) factors also influence a reaction? Is it the arrangement or state of the chemicals? Is it too related to other physical properties to ignore them?

Please name the most important ones.

  • $\begingroup$ Welcome to Chemistry.SE! These are a actually a lot of rather general questions for a first post. Would you mind to narrow the scope and ask something more specific first? $\endgroup$ Commented Feb 9, 2014 at 8:57
  • $\begingroup$ @Klaus_Warzecha Thank you for your feedback. But I don't know how to make this question more specific. $\endgroup$
    – Felix D.
    Commented Feb 9, 2014 at 10:11

1 Answer 1


For predicting chemical reaction you should use classical mechanics to take in account the simple interactions between the molecules and quantum mechanical for all the aspects concerning the molecule itself and complex interactions. Knowing the principal parameter such as temperature and pressure that could describe the system with the classical mechanics (kinetic energy etc. etc.) is not enough for predicting the reaction with ab initio methods. Adding the quantum mechanical contribute is mandatory and quite hard to do. A amateur chemist do not have neither the skills nor the computation power require to make such calculations. For the moment you can't do that with any software but the last Nobel was won by three theoretical chemists who are dealing with this topic. Have a look here for more information.

In your case where the reactions are well known you can use a chemical reactions database like the NIST one. This is a simple query: enter image description here

And this is the...

enter image description here

  • $\begingroup$ So it is not possible by only considering the valency and electronegativity? OK, that would've been too easy. ;) $\endgroup$
    – Felix D.
    Commented Feb 9, 2014 at 20:46
  • $\begingroup$ @felixd I'm afraid not... :-) $\endgroup$
    – G M
    Commented Feb 10, 2014 at 15:23
  • 2
    $\begingroup$ This article came recently. It shows how over dependence on computational results can be disasterous! cen.acs.org/articles/93/web/2015/03/… $\endgroup$
    – ipcamit
    Commented Jul 23, 2015 at 5:28

Not the answer you're looking for? Browse other questions tagged or ask your own question.