U=3/2 nRT

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Norman Dis4C
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

U=3/2 nRT

Postby Norman Dis4C » Sun Feb 09, 2020 11:40 am

Can someone explain the idea of the equation U=3/2 nRT and how it is used?

Daria MacAuslan 1H
Posts: 50
Joined: Sat Aug 17, 2019 12:16 am

Re: U=3/2 nRT

Postby Daria MacAuslan 1H » Sun Feb 09, 2020 11:49 am

I dont think we covered this in class so I am unsure if it is necessary for the exam, especially since we focused more on changes in internal energy, rather than fixed amounts...

Jared Khoo 1G
Posts: 107
Joined: Wed Sep 18, 2019 12:16 am

Re: U=3/2 nRT

Postby Jared Khoo 1G » Sun Feb 09, 2020 5:04 pm

U is the same as Eth I believe, which is the thermal energy an object has. Therefore, U is also determined by temperature and is equal to the average kinetic energy per mole multiplied by the number of moles (n).

Posts: 95
Joined: Sat Aug 17, 2019 12:17 am

Re: U=3/2 nRT

Postby AniP_2D » Sun Feb 09, 2020 5:19 pm

You would use this equation when you are asked to find deltaU at a constant volume.

Justin Quan 4I
Posts: 104
Joined: Sat Sep 14, 2019 12:17 am

Re: U=3/2 nRT

Postby Justin Quan 4I » Mon Feb 10, 2020 1:18 pm

To add on, ∆U=3/2 nRT comes from the equation ∆U = q + w. Under constant volume conditions, w=0, thus ∆U = q. Since q = n C ∆T and Cv=(3/2) R, we get the equation ∆U=3/2 nRT.

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