- From: Wacek Kusnierczyk <Waclaw.Marcin.Kusnierczyk@idi.ntnu.no>
- Date: Tue, 31 Mar 2009 14:30:59 +0200
- To: Matthias Samwald <samwald@gmx.at>
- CC: Phillip Lord <phillip.lord@newcastle.ac.uk>, public-semweb-lifesci <public-semweb-lifesci@w3.org>

Matthias Samwald wrote: > >>> Reaction equations describe stochastic processes, that's why you can >>> have non-integer molecule numbers >> >> I think you can't have non-integer molecule numbers because it makes >> no chemical sense. Half a molecule is a whole molecule of a different >> kind. > > You can have reaction equations that look like > > N2O5 ---> 2 NO2 + 1/2 O2 just that the coefficient 1/2 is not an absolute molecule number here. it is a relative molecule number; here, the ratio of the number of molecules of O2 to the number of molecules of N2O5 participating in reactions described by the equation. i'd agree that having non-integer *molecule numbers* sounds nonsense, but having non-integer *relative molecule numbers* certainly doesn't. in any case, the equation N2O2 -> 2 NO2 + 1/2 O2 is equivalent to 2 N2O2 -> 4 NO2 + O2 and you can always (i guess) avoid non-integer coefficients by multiplying both sides by a constant. > > Which means that the number of O2 molecules that would be produced if > the equilibrium would be shifted to the absolute right side is 1/2 of > the number of molecules of N2O5 that would exist if the equilibrium > would be shifted to the absolute left. This only makes sense if we > interpret reaction equations as descriptions of pools of molecules and > their stochastic processes, rather than single molecules. Representing > reaction equations as processes where the participants are single > molecules is wrong. In that case, one cannot blame OWL if one is > running into inconsistencies. +1 vQ

Received on Tuesday, 31 March 2009 12:32:26 UTC