Delta U in Isothermal Systems

[SLai_1I]

Is delta U always equal to zero in isothermal systems (reversible or irreversible)?

[Victor Li 2A]

If I remember correctly, Delta U = 0 for both reversible and irreversible isothermal conditions.

[Hasmik Dis 2F]

Yes. Delta U has to be 0 because an isothermal means constant temperature.

[ColmConnolly3D]

Yup! A good way to think about this for me is that any energy gained through heat must be equal to the amount lost through work (or vice versa) for the temperature to remain constant (or that it would have to go somewhere else like in a phase change). Thus, if q=-w, ∆U = q + (-q) = 0 (And vice versa if we switch the variables.

Hope this helps!

Colm

[Aanya Tanti 3C]

Yes, delta U is always constant in isothermal reactions as any energy lost via heat is replaced by the system.

[Susanna Givan 2B]

If the system is isothermal, then Delta U would be 0 because the heat lost is replaced by the system/surroundings.

[Gerardo Ortega 2F]

Yes, delta U is always equal to zero in isothermal systems (whether reversible or irreversible).

[Edgar Velazquez 2K]

Yes, delta U is always equal to 0 in isothermal systems because there is no net change in heat/energy. Any heat/energy that is lost or gained is "put back" by either the system or the surroundings.