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Isothermal expansion

Posted: Wed Feb 05, 2020 7:03 pm
by Chloe Alviz 1E
Why is ∆U = 0 for isothermal expansion (or compression) of an ideal gas?

Re: Isothermal expansion

Posted: Wed Feb 05, 2020 7:21 pm
by Adriana_4F
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.

Re: Isothermal expansion

Posted: Sun Feb 09, 2020 4:48 pm
by Jared Khoo 1G
Delta U is equivalent to 3/2 NKB(Delta T), so if T is constant then Delta U is constant as well.