gibbs free units

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Samantha Chung 4I
Posts: 77
Joined: Wed Oct 03, 2018 12:16 am

gibbs free units

In the textbook examples given, sometimes gibbs free energy is given in kJ/mol and sometimes it is just kJ, how do I know which one to write? (In both cases, the units cancel out to kJ).

705170809
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am
Been upvoted: 1 time

Re: gibbs free units

I believe that in both cases, gibbs free energy is measured in kJ overall. The only time I think Gibbs free energy is measured in kJ/mol is when you have to use the delta G reaction formula that requires the delta G (products) - delta G (reactants). The individual compounds in the reaction will be measured in kJ/mol, but eventually the mol will cancel out since you are multiplying by the amount of moles in the rxn.

Arshiya
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 1 time

Re: gibbs free units

In addition, if the question asks for the Gibbs free energy of formation of the reaction the units should be kJ/mol. Just pay attention to what the question is asking.

Aleeque Marselian 1A
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

Re: gibbs free units

I believe Gibbs Free Energy should almost always be measured in kj overall, however if the question asks for the Standard Gibbs Free Energy of formation of the reaction then the units should be kj/moles. Hope this helps!