Expansion

[Jasmine Botello 2F]

When the temperature is constant and pressure and volume are both changing, this means that work is being done BY the system right? aka expansion? or am I missing something?

[Lucian1F]

If the volume is expanding then the system is doing work

[Brandon Fujii 1K]

In the internal energy equation

Delta U = q+w

our w value would be negative because the w is work done by the surroundings (system does work to expand)

[William Xu Dis 1D]

It would depend on how the pressure and volume are changing. If the pressure is external, the surroundings are performing work on the surroundings. If you are referring to the internal pressure of the system, then if the pressures or volume increases, then the system is doing work. If the volume increases, it is called expansion work.