I am interested on oxidation of a solid surface (SiC), where an O replaces a C
atom, forming a Si-O-Si onto the surface, with CO desorption.
Roberto
________________________________
From: N H <neyh...@gmail.com>
To: SIESTA-L@listserv.uam.es
Sent: Friday, January 16, 2009 10:51:27 PM
Subject: Re: [SIESTA-L] Hess's law
If the reaction is in gas phase u can use [A] = [A0] + RTln(p/p0) and this
should give u the chemical potential ... if u have solid reagents the chemical
potentials are not sensitive to the temperature, and I guess u dont have
anything in solution.
Best Regards
NH
On Fri, Jan 16, 2009 at 10:27 PM, Roberto Veiga <roberto.ve...@ymail.com> wrote:
Ok, so I have how to know if the reaction is endothermic or not just by
calculating the four isolated systems (the two reactants and the two products).
But in order to know if the reaction is spontaneous for T>0, I have to compute
also the change in the entropy. It is not that easy, I guess...
Roberto
________________________________
From: N H <neyh...@gmail.com>
To: SIESTA-L@listserv.uam.es
Sent: Friday, January 16, 2009 10:11:41 PM
Subject: Re: [SIESTA-L] Hess's law
If you have correwctly calculated all intial and finals states the answer is
yes!
On Fri, Jan 16, 2009 at 10:02 PM, Roberto Veiga <roberto.ve...@ymail.com> wrote:
Hello,
if I have a substitution reaction as follows:
AB+CD-->AC+BD
and I calculate the four systems isolated with Siesta, can I calculate the
enthalpy of such a reaction as stated by the Hess's law? Or there is any
subtlety?
Thanks in advance,
Roberto
