## Constant Pressure

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

Victoria Zheng--2F
Posts: 103
Joined: Fri Aug 09, 2019 12:17 am

### Constant Pressure

Hello. I don't quite understand what is the meaning of there is no expansion work done when the pressure is constant?

Rachel Yu 1G
Posts: 113
Joined: Fri Aug 09, 2019 12:15 am

### Re: Constant Pressure

Do you mean no expansion work done when the volume is constant? Since w= -PdeltaV, no change in volume makes deltaV (and therefore w) equal to 0.

Jessica Li 4F
Posts: 115
Joined: Fri Aug 09, 2019 12:16 am

### Re: Constant Pressure

When pressure is constant, there is expansion work done, which can be calculated using the equation w = -P(deltaV). However, at constant volume, delta V is 0, so w will be 0 and no work will be done.

205291012
Posts: 50
Joined: Mon Nov 11, 2019 12:17 am

### Re: Constant Pressure

There is no expansion work done at constant volume. This is because for expansion work to be done the piston needs to move from a lower volume to a higher volume.

There is expansion work done at constant pressure.