## Work done on or by system

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

Sophia Kim 1C
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Joined: Fri Sep 29, 2017 7:04 am
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### Work done on or by system

If there is an increase in volume is the system inside always doing work (so therefore negative work) and if there is a decrease in volume the system inside is it always getting work done on it (so work is positive)?

Troy Tavangar 1I
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### Re: Work done on or by system

If work is negative, it is done by the system. If work is positive, work is done on the system.

Katelyn B 2E
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

### Re: Work done on or by system

For irreversible expansions, keep the equation w=-PΔV in mind. If there is an increase in volume (+ΔV), work will be negative, meaning work was done by the system. If there is a decrease in volume (-ΔV), work will be positive, meaning work was done on the system.