Van't Hoff Equation - Killer Exam Problem (Thermodynamics)

Use the Van't Hoff Equation to solve for a Killer exam problem, common in general chemistry thermodynamics. If you can solve this problem using the Van't Hoff Equation and understand what's going on, then good work!
Note that the ΔG for the reaction should be -32.90 kJ/mol but based on the information given, the steps are good.
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[@brainynerdtutor1626]

Check out these "need-to-knows" about the van't Hoff Equation: kzbin.info/www/bejne/eH-WfmyQltqXo5o

[@hannagoyeneche9271]

This is exactly what i needed!

[@twokidsmovies]

Is the reaction free Gibbs energy given in the question the energy for 2NH3 (the product) or is it the sum of the reactants? I am just trying to figure out what that number corresponds to in the reaction equation.

[@brainynerdtutor1626]

The reaction Gibbs energy is for 2 moles on NH3. The 'per mol' in the units are like 'per mole of the reaction'. So imagine that the reaction occurred a mole times (1.022x10^23 times), then 1 mol of N2 would react with 3 mol of H2 to produce 2 mole of NH3.

[@twokidsmovies]

@brainynerdtutor1626 I appreciate your help. I'm working on finding the equilibrium constant for the dissociation reaction of ammonium sulfate. I have spent like 3 days trying to find the thermodynamic data, and I think I calculated the log K value at 100 C (what I need for modeling) but I can't tell if I did it right. I have the enthalpy, and I did thr calculations, is there anyway (I really don't want to bother you) that I could send you the page I have? I just need to make sure my Log K value is correct before I update the GWB database.

[@brainynerdtutor1626]

Sure, send email me a photo of your work: [e-mail]

[@twokidsmovies]

@@brainynerdtutor1626 thank you so much. Just sent the email!

[@joshg.6536]

I am getting for K_1 = 13.40 -because delta G = 2 * delta_B G(NH3) = 2 * (-16.45 KJ/mol) = - 32.9 KJ/mol. For K_2 i got 7.441. Where is here the mistake? Thanks :)

[@brainynerdtutor1626]

Hi Josh. The mistake is actually in the question. ΔG(NH3) = -16.45 kJ/mol but the reaction is for the formation of 2 moles of NH3 so ΔG should be double that, -32.90 kJ/mol, as you correctly stated. However, the question listed ΔG for the reaction (incorrectly) as -16.45 kJ/mol so that's the number that was used.

[@joshg.6536]

@@brainynerdtutor1626 Hi Tutor :) Thanks for the answer. So my result K_2 = 7.441 is correct?

[@fxst]

killer problem bro thanks