## chapter 9, number 13

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

Belle Calforda3f
Posts: 67
Joined: Fri Sep 29, 2017 7:07 am

### chapter 9, number 13

In 9.13, the problem says 3.00 liters of Nitrogen gas at 18.5 degrees c was compressed suddenly and irreversibly to .500 liters by driving in a piston. The temperature changed to 28.1 degrees c. calculate the total change in entropy.

So I know that I need to independently calculate delta s for the change in volume and then the change in T, but when I looked at the solutions the book used this equation: deltaS=nRln(T2/T1), for the temperature part.

My question is how come the equation doesn't include a cv or cp like the one for temperature on the equation sheet?

Humza_Khan_2J
Posts: 56
Joined: Thu Jul 13, 2017 3:00 am

### Re: chapter 9, number 13

Check out the solution manual error guide (https://lavelle.chem.ucla.edu/wp-conten ... rs_6Ed.pdf). This problem is incorrect; you'd want to use Cv, which is 5/2R for a diatomic ideal gas.

Belle Calforda3f
Posts: 67
Joined: Fri Sep 29, 2017 7:07 am

ohhhh THANKSSSS