[SIESTA-L] Hess's law

2009-01-16 Thread Roberto Veiga
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

Re: [SIESTA-L] Hess's law

2009-01-16 Thread N H
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.comwrote: Hello, if I have a substitution reaction as follows: AB+CD--AC+BD and I calculate the four systems isolated with Siesta, can I

Re: [SIESTA-L] Hess's law

2009-01-16 Thread Roberto Veiga
... 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

Re: [SIESTA-L] Hess's law

2009-01-16 Thread N H
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

Re: [SIESTA-L] Hess's law

2009-01-16 Thread Roberto Veiga
: [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