Work (in general)  [ENDORSED]


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

Work (in general)

Postby Kayla Tchorz-Dis 1F » Sat Jan 13, 2018 8:30 pm

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)

Postby Esin Gumustekin 2J » Sat Jan 13, 2018 8:46 pm

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)

Postby Tiffany Dao 1A » Sat Jan 13, 2018 8:59 pm

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)

Postby Jana Sun 1I » Thu Jan 18, 2018 10:31 pm

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).

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

Re: Work (in general)  [ENDORSED]

Postby Maria1E » Fri Jan 19, 2018 4:03 pm

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.

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