Work (in general) [ENDORSED]

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

Kayla Tchorz-Dis 1F
Posts: 30
Joined: Thu Jul 13, 2017 3:00 am

Work (in general)

How do you know which work equation to use?

Esin Gumustekin 2J
Posts: 57
Joined: Thu Jul 27, 2017 3:01 am

Re: Work (in general)

To find work I always use Work = Fd (opposing force x distance moved). I don't think we learned any other formulas including work in lecture yet.

Tiffany Dao 1A
Posts: 32
Joined: Fri Sep 29, 2017 7:05 am

Re: Work (in general)

In the book there is also an equation for work that relates the external pressure and volume.
w = -Pex x Delta V

Jana Sun 1I
Posts: 52
Joined: Sat Jul 22, 2017 3:00 am

Re: Work (in general)

For reversible reactions, you would use work= -nRT(ln(Vf/Vi)) or work= -nRT(ln(Pi/Pf)). For irreversible reactions, which we'll probably need to know better for the first exam at least, we use the work equation described above aka work= -(Pext)(delta V).

Maria1E
Posts: 61
Joined: Sat Jul 22, 2017 3:01 am

Re: Work (in general)  [ENDORSED]

For irreversible reactions, use w = -P(delta V). However, depending on the information you are given you may also need to use w = -(delta n)RT since PV = nRT.