## Hw question 5J.15

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

kennedyp
Posts: 56
Joined: Tue Nov 13, 2018 12:18 am

### Hw question 5J.15

For the first part of part a , I used the standard gibbs free energy equation and was able to correctly find the first K, but I'm using the Van't Hoff equation to find the second K and I keep getting one. I don't know if the book made the mistake or if I'm doing something wrong in my calculations (the book answer is 1.0 x 10^-7). Here's the question for reference: ( 5J.15 Calculate the equilibrium constant at 25 8C and at 150 8C for each of the following reactions, using data available in Appendix 2A:
(a) NH4Cl(s) ∆ NH3(g) 1 HCl(g) )

Justin Sarquiz 2F
Posts: 106
Joined: Fri Aug 30, 2019 12:15 am

### Re: Hw question 5J.15

I found delta G* using delta G*=delta H* - Tdelta S*
You have to solve for delta H* and delta S* and then use those values with the temperatures to find delta G*
deltaG*= -RT ln K
You know everything except for K
Then do this same procedure for the other temperature

rachelle1K
Posts: 109
Joined: Sat Sep 07, 2019 12:16 am

### Re: Hw question 5J.15

I was looking at this question in other chemistry posts, and someone said we have to use the equation ln(K2/K1) = (deltaH/R)[(1/T1) - (1/T2)] Though I am not really sure how to apply it.