Work done by gases

[Olivia Peony Dis 2A]

When do we use W=-p(deltaV) or W-p(dV)
I understand that the derivative term means an instantaneous change, so that it should mean that dV is used when change in volume is small. However, I am unsure if the reasoning is exactly correct or is there a better explanation.

Thank you!

Olivia Peony Dis 2A

[Reza Hemmati 3L]

Hi!

I think that, for this class, we'll be using the first one. The second implies a rate, which I don't think we're discussing until kinetics(the last unit/topic in 14B). I may be wrong, though.

Hope this helps!

[Alex FreeWolf 2E]

Hi,

So far we have only used W=-p(deltaV). I believe the other equation will be used at a later time so for now just focus on the first one.

Hope this helps!

[Jeffrey Yang 3I]

To add on to the other answers, in most problems so far and thus far in this class, we have been looking at net changes in two instantaneous points in the system. This means that we can simplify the question by removing the need to look at continuous change through rates. Thus, -pV is the equation we can use to look at the change between two points in the system.

[Emmaplant1c]

Does anyone have any good examples of graphs that would demonstrate work done by gases?