Midterm question 6a

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Ishan Saha 1L
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Midterm question 6a

Postby Ishan Saha 1L » Mon Feb 26, 2018 2:01 pm

On this problem on the midterm, both A and B were considered correct answers. For future reference, what answer is correct? Should we think that any gas always has more entropy than any liquid? If not, how do we know if a molecule is complex enough to have more entropy as a liquid than a simple molecule as a gas.

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Re: Midterm question 6a

Postby Chem_Mod » Mon Feb 26, 2018 2:04 pm

Hello,

Please include the question that you are asking in regards to.

Thank you.

Ishan Saha 1L
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Re: Midterm question 6a

Postby Ishan Saha 1L » Tue Feb 27, 2018 5:30 pm

Hi,

The question was
"Which of the following statements is correct?"
and both A and B (shown below) were accepted as correct answers on the past midterm. My question is, in the future, which answer is correct? Should we think that any gas always has more entropy than any liquid? If not, how do we know if a molecule is complex enough to have more entropy as a liquid than a simple molecule as a gas?

Options A and B:
A. C8H18(l) (at 298 K) has higher molar entropy than CH4(g), because C8H18 is a larger molecule than CH4, and larger molecules have more chemical bonds and can store energy in more ways than smaller molecules.
B. CH4 as higher molar entropy than C8H18 (l) because gases have a higher entropy than liquids.

Hope that clarifies my question, and Thank you!

Michael Downs 1L
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Re: Midterm question 6a

Postby Michael Downs 1L » Fri Mar 16, 2018 10:11 pm

I think it has something to do with the wording of the answers

Cristina Sarmiento 1E
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Re: Midterm question 6a

Postby Cristina Sarmiento 1E » Fri Mar 16, 2018 10:16 pm

They were both correct because complex molecules have more entropy than less complex molecules and gas has more entropy than liquid.

Ilan Shavolian 1K
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Re: Midterm question 6a

Postby Ilan Shavolian 1K » Sat Mar 17, 2018 8:19 pm

I believe you can safely assume that the entropy difference from liquid to gas is going to more than the increase in entropy of a more complex molecule.


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