When to use this equation


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sofiakavanaugh
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Joined: Thu Jul 13, 2017 3:00 am
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When to use this equation

Postby sofiakavanaugh » Sun Feb 11, 2018 9:26 pm

Hi,

I was wondering in what specific situations we would need to use w=-pdeltaV versus other work equations

Does the temperature need to be constant?

Thanks!

Aijun Zhang 1D
Posts: 53
Joined: Tue Oct 10, 2017 7:13 am

Re: When to use this equation

Postby Aijun Zhang 1D » Sun Feb 11, 2018 9:34 pm

When the pressure is constant, we use w = -Pext

When temperature is constant (isothermal), we use w = -nRT ln (Vfinal/Vinitial)

Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Re: When to use this equation

Postby Nha Dang 2I » Mon Feb 12, 2018 2:49 am

w = -nRT ln (Vfinal/Vinitial) is also used when the pressure is not kept at a constant.

snehabhargava
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am

Re: When to use this equation

Postby snehabhargava » Mon Feb 12, 2018 11:11 am

That equation is used when the pressure is constant.

McKenna disc 1C
Posts: 60
Joined: Fri Sep 29, 2017 7:04 am

Re: When to use this equation

Postby McKenna disc 1C » Mon Feb 12, 2018 2:04 pm

Aijun Zhang 1D wrote:When the pressure is constant, we use w = -Pext

When temperature is constant (isothermal), we use w = -nRT ln (Vfinal/Vinitial)


Are these the only two scenarios we'll likely be dealing with? Thanks!


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