Hello all, In my physics textbook they discuss work done by ideal gas processes. The equation they give is Wgas = pΔV. I'm trying to figure it out if this is work done ON the gas by the surroundings, or work done BY the gas on surroundings. From a previous chapter, they presented the conservation of energy equation as Ei + Wnet,ext = Ef. Work in this equation is the net, external work on the system, such that +W is work by the surroundings on the system, and -W is work by the system on the surroundings. It would seem from this preliminary chapter that we would be defining any W as work ON the system by surroundings. However Wgas can't possibly be work done ON the gas, because if a gas is expanding, it supposedly has +Wgas even though it is doing work on the surroundings (therefore Wnet,ext should be negative). Could anybody confirm my thinking and does anybody know a good way to distinguish these two?