So I basically have a general question, not for any compound in particular, just a standard protocol. If you know the balanced chemical reaction to produce a desired compound, but the ΔS's, ΔH's, or ΔG's of formation or deformation for your complexes are not listed in literature tables how do you figure out it?
Also, does knowing the ΔG of a chemical reaction provide a researcher with mathematical information beyond simply putting a metric on the spontaneity or favorability of a chemical reaction occurring under standard or specific temperature and pressure conditions?
Explanations and research papers with clearly defined methods are appreciated.
Thank you.
The answer to your question, refer to the address
http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Thermodynamics/State_Functions/Free_Energy/Gibbs_Free_Energy
Best regards
Yuri M,
your citation still relies on ΔS and ΔH tables of the chemical species, so that's the tabular method that I wasn't interested in. But it seems that Calculating Gibbs Free Energy via electrochemistry and calculating K(sub eq) of the reaction is useful.
Can you provide a citation for the proper procedure to collect the raw data?
Thanks.
I am not an experimentalist, so I can offer no help for how to calculate the properties you wish via experiments. However in regards to the second part, the... mathematical part of your questions, I think you would benefit from the classic book on chemical reactions that is by Smith & Missen titled " Chemical reaction equilibrium analysis: theory and algorithms". It is out of print, but available from the author (or a university library perhaps). Professor William R. Smith is on researchgate, and a little Google searching will lead to his University of Guelph email address.
If you have the \Delta G then you can calculate the equilibrium constant, which is a very useful property, and I refer to Atkin's Physical Chemistry, Chapter 7, by Atkins and De Paulo for more details on all the things you can do with that.
Also, if you are modelling the reactions and have the \Delta G's, you can calculate your standard state chemical potentials (ch. 9.4 Smith & Missen), so you just need a model for the excess chemical potential, then you can calculate the Gibbs energy of the mixture, and use a numerical procedure to adjust the composition of the components until you have the minimum in the Gibbs energy landscape (Smith and Missen cover this really well). At the minimum you have your equilibrium composition, which, presumably, is what you were after?
Best of luck,
Braden
Experimentally. Carry out the reaction between the two reactants at constant pressure and tempererature. You expect when the concentration of the reactants will stop changing. Hence came the equilibrium in the reaction. Determine the equilibrium concentration. According to equation 1.14 (my link) determine the equilibrium constant of reaction. For comparison, all constants determined under standard conditions. Then, according to equation 1.15 calculates energy Gibbs.
Gibbs Energy in Electrochemistry. Measure of potentials 2 electrds (OX and Red) in volts (joules per coulomb) . Regarding the standard hydrogen electrode. The difference in the electrode potentials determine the electromotive force cell or E = cell potential in volts (joules per coulomb). According to equations 1.24 and 1.25 define the Gibbs energy of the reaction.
Best regards.
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