Temperature in Work Equations


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Amy Lefley 1J
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Temperature in Work Equations

Postby Amy Lefley 1J » Wed Feb 06, 2019 11:07 pm

For the equation W=-nRTlnV2/V1, if the temperature stays constant, why is it included in the equation but for the other work equation W=-PdeltaV if the temperature changes along the pathway, why is temperature not included in the equation?

melodyzaki2E
Posts: 61
Joined: Fri Sep 28, 2018 12:18 am

Re: Temperature in Work Equations

Postby melodyzaki2E » Wed Feb 06, 2019 11:56 pm

in the second equation the pressure is constant and the volume is changing in response so everything on the other side of the ideal gas law equation stays constant, i'm not sure why we don't include it though.

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

Re: Temperature in Work Equations

Postby Nicole Elhosni 2I » Sat Feb 09, 2019 10:24 am

I think temperature is not included in w=-pΔV, because it is a closed system and the pressure is constant, so when you change the temperature by adding or removing heat, the only thing that it affects is the volume. So the temperature change is manifested in the volume.

JadeSebti1L
Posts: 35
Joined: Fri Sep 28, 2018 12:19 am

Re: Temperature in Work Equations

Postby JadeSebti1L » Sat Feb 09, 2019 10:32 am

I think you have to include T in the first equation because when you derive it you have to use the integral of P in respect to volume, but you ultimately replace P with the other side of the ideal gas equation (nRT/V). When you take the integral, you can pull out the "-nRT" because it's technically a constant. You still have to include it because if it wasn't there you wouldn't be taking the integral of P in respect to volume, which is work.


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