## Expansion

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

Jasmine Botello 2F
Posts: 67
Joined: Fri Sep 29, 2017 7:04 am

### Expansion

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
Posts: 87
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: Expansion

If the volume is expanding then the system is doing work

Brandon Fujii 1K
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: Expansion

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
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

### Re: Expansion

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.