Calculating enthalpy change for NaOH and HCl neutralization

[stargazer]

Chemistry Help-Enthalpy

Hi. I would very much like to know how to calculate the enthalpy change of a neutralization reaction, for example, NaOH(aq) and HCl(aq).
Thank you very much.

 

[himanshu121]

Hi. I would very much like to know how to calculate the enthalpy change of a neutralization reaction, for example, NaOH(aq) and HCl(aq).
Thank you very much.

Strong acid + strong base has an enthalpy of neutrailzation = -13.7 Kcal

which is the case here

 

[ShawnD]

I get a different answer based on some data tables I have.
http://myfiles.dyndns.org/datasheets/chem_enthalpy1.jpg
http://myfiles.dyndns.org/datasheets/chem_enthalpy2.jpg

Energies are in KJ

delta H = [water + sodium chloride] - [hydrogen chloride + sodium hydroxide]
delta H = [-285.8 - 411.2] - [-92.3 - 425.6]
delta H = -179.1 KJ / mol

Thats about -43 Kcal / mol

 

[GCT]

Start from the standard elements in their most stable state at standard conditions. Unless the enthalpy of formation for each compound is provided to you already, it can be a bit complex. Here is an example...

http://groups.msn.com/GeneralChemistryHomework/general.msnw?action=get_message&mview=0&ID_Message=116&LastModified=4675466454162512526