U=3/2 nRT

[Norman Dis4C]

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

[Daria MacAuslan 1H]

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]

U is the same as E_th 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).

[AniP_2D]

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

[Justin Quan 4I]

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 C_v=(3/2) R, we get the equation ∆U=3/2 nRT.