## HW 11.83

$\ln K = -\frac{\Delta H^{\circ}}{RT} + \frac{\Delta S^{\circ}}{R}$

chemstudent_1K
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### HW 11.83

Calculate the equilibrium constant at 25C and at 150C for each of the following reactions, using data available in appendix 2A:

A. NH4Cl(s)<->NH3(g)+HCl(g)

Does it matter whether we use deltaG=sum of deltaG(products)-deltaG(reactants) or deltaG=deltaH-TdeltaS to find the standard free energy? And does it matter whether we use deltaG=-RTlnK or lnK=(-deltaH/RT)+(deltaS/R) to solve for K for both temperatures?

Chem_Mod
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### Re: HW 11.83

Both methods could be used to solve the problem but they will probably not give the exact same answer. Use the method that is dictated in the question, in this case, get values from Appendix

AKatukota
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### Re: HW 11.83

So why exactly is the delta G = delta H - T delta S needed just because there are two different temperatures?

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### Re: HW 11.83

Can we also use the ln(k2/k1)=-delta H standard/R[1/t1 -1/t2] to solve this problem or do we have to find the separate standard G to find the values of K?

805097738
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### Re: HW 11.83

Eesha Chattopadhyay 2K wrote:Can we also use the ln(k2/k1)=-delta H standard/R[1/t1 -1/t2] to solve this problem or do we have to find the separate standard G to find the values of K?

the question says to use data in the appendix so I'd find the standard G to find K values