## Quiz 1 Prep # 9

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

samchung2f
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### Quiz 1 Prep # 9

A sample of 1 mol of gas initially at 1 atm and 298 K is heated at constant pressure to 350 K, then the gas is compressed isothermally to its initial volume and finally it is cooled to 298 K at constant volume. Which of the following values is 0?
DeltaSsurr and DeltaG

DeltaSsys and DeltaSsurr

q and w

W

DeltaG and DeltaSsys

For this question, I know that DeltaSsys and DeltaG are state functions so they are 0. But what I was having trouble understanding is how do you know how DeltaSsurr changes in this question? I know that obviously the entropy of the system does not change since it goes back to the same state, but how does this affect DeltaSsurr?

Chem_Mod
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### Re: Quiz 1 Prep # 9

Because $\Delta$S (total) > 0

Christopher Reed 1H
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### Re: Quiz 1 Prep # 9

Hi!

I am having difficulty understanding why dS(total) is positive. What are the cues in the question that give this away? Furthermore, if a reaction is spontaneous (dS(total) >0) why is it that dG is not less than zero?

I think I'm a little mixed up...if anyone could help answer my questions I would greatly appreciate it! Thank you in advance (: