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- Homework Statement
- A PV diagram shows an isobaric expansion, I'm asked to know the signs of: work done on, heat added to, and change in energy content of the system.

- Homework Equations
- W= integral (P dV), dU = Q + W

**Homework Statement:**A PV diagram shows an isobaric expansion, I'm asked to know the signs of: work done on, heat added to, and change in energy content of the system.

**Homework Equations:**W= integral (P dV), dU = Q + W

Since this is an expansion, the system does work on the surrounding and therefore the work done on the system is -ve.

Also, to preserve a constant pressure, heat has to be added, therefore heat added is +ve.

The energy content(dU) is the sum of those too, and since the process is isobaric not adiabatic, dU has a value.

How can I know whether it is negative or positive?