Higher Molar Entropy?

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Paula Dowdell 1F
Posts: 72
Joined: Tue Nov 15, 2016 3:00 am

Higher Molar Entropy?

Postby Paula Dowdell 1F » Sun Feb 11, 2018 1:10 pm

Can someone explain the reasoning behind this to me?

"Which substance in each of the following pairs has the higher molar entropy: (a) 1 mol CO2(g) at 25 C and 1 bar or 1 mol CO2(g) at 25 C and 3 bar"

A: CO2(g) at 1 bar, because disorder increases with volume.

I thought bar corresponded to pressure?

Varsha Sivaganesh 1A
Posts: 51
Joined: Thu Jul 13, 2017 3:00 am

Re: Higher Molar Entropy?

Postby Varsha Sivaganesh 1A » Sun Feb 11, 2018 1:14 pm

Bar does correspond to pressure. But I think it's because since there is less pressure, we may be able to assume it is because the volume is greater.

Diane Bui 2J
Posts: 61
Joined: Sat Jul 22, 2017 3:00 am

Re: Higher Molar Entropy?

Postby Diane Bui 2J » Sun Feb 11, 2018 1:34 pm

To add on to the answer above, pressure is inversely proportional to volume according to Boyle's Law, so the smaller the pressure, the greater the volume. Since 1 bar is less than 3 bar, the volume is greater, and hence, entropy increases.

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