Example 9.5

Volume:
Temperature:

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Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Example 9.5

Postby Nha Dang 2I » Mon Feb 12, 2018 4:05 pm

In one experiment, 1.00 mol O2(g) was compressed suddenly (and irreversibly) from 5.00 L to 1.00 L by driving in piston, and in the process its temperature was increased from 20.0 C to 25.2 C. What is the change in entropy of the gas?

In Step 2, why did they use the heat capacity of argon in deltaS=(Cv)ln(T2-T1)?

Lauren Seidl 1D
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

Re: Example 9.5

Postby Lauren Seidl 1D » Mon Feb 12, 2018 4:15 pm

If you look at the bottom of page 325 under the example, it says to assume that argon is an ideal gas, so I am assuming that is why you would use argon's heat capacity.

Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Re: Example 9.5

Postby Nha Dang 2I » Mon Feb 12, 2018 9:11 pm

But why would you use argon when the question is asking about oxygen?

Justin Yu 3H
Posts: 36
Joined: Fri Sep 29, 2017 7:07 am

Re: Example 9.5

Postby Justin Yu 3H » Mon Feb 12, 2018 9:40 pm

Argon is very very similar to the ideal gas. The molar heat capacity at constant volume for argon is the same as 3/2 R, that of a monoatomic ideal gas. So even though they write argon, you can just interpret that as viewing oxygen as an ideal gas.


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