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Re: blog: semantic dissonance in uniprot

From: Egon Willighagen <egon.willighagen@gmail.com>
Date: Thu, 2 Apr 2009 16:52:55 +0200
Message-ID: <6aeb064b0904020752y192144e4m7a28a6b810897c4f@mail.gmail.com>
To: Oliver Ruebenacker <curoli@gmail.com>
Cc: Wacek Kusnierczyk <Waclaw.Marcin.Kusnierczyk@idi.ntnu.no>, Matthias Samwald <samwald@gmx.at>, Phillip Lord <phillip.lord@newcastle.ac.uk>, public-semweb-lifesci <public-semweb-lifesci@w3.org>
On Tue, Mar 31, 2009 at 2:49 PM, Oliver Ruebenacker <curoli@gmail.com> wrote:
> On Tue, Mar 31, 2009 at 8:30 AM, Wacek Kusnierczyk
> <Waclaw.Marcin.Kusnierczyk@idi.ntnu.no> wrote:
>> 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.

Importantly, these are equations, not actual chemical reactions. It's
not N2O2 that is reacting here... very likely, the number of reactions
in this equations != 1.

>  What about this statement:
>
>  "Two grams of hydrogen react with 16 grams of oxygen to 18 grams of water"

Indeed. Reaction equations often just describe the stoichiometry of
the macroscopic reaction. The above are not reaction mechanism.

So, whether to have integer, or non-integer coefficients, depends on
the definition to what they apply.

Egon


-- 
Post-doc @ Uppsala University
http://chem-bla-ics.blogspot.com/
Received on Thursday, 2 April 2009 14:53:32 UTC

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