Isothermal expansion


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Chloe Alviz 1E
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Joined: Sat Aug 17, 2019 12:17 am

Isothermal expansion

Postby Chloe Alviz 1E » Wed Feb 05, 2020 7:03 pm

Why is ∆U = 0 for isothermal expansion (or compression) of an ideal gas?

Posts: 74
Joined: Fri Sep 28, 2018 12:29 am

Re: Isothermal expansion

Postby Adriana_4F » Wed Feb 05, 2020 7:21 pm

One of the characteristics of an ideal gas is that there is no interaction between gas molecules. This means the molecules will not have any potential energy so the only contributor to the change in internal energy would be its kinetic energy due to its absolute temperature. Since it is isothermal, T=0 so neither kinetic nor potential energy would contribute to the change in internal energy so deltaU=0.

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

Re: Isothermal expansion

Postby Jared Khoo 1G » Sun Feb 09, 2020 4:48 pm

Delta U is equivalent to 3/2 NKB(Delta T), so if T is constant then Delta U is constant as well.

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