4B.13


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Letty Liu 2C
Posts: 105
Joined: Fri Aug 09, 2019 12:16 am

4B.13

Postby Letty Liu 2C » Sun Feb 02, 2020 3:59 pm

Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T 5 305 K, P 5 1.79 atm, and V 5 4.29 L: (a) irreversible expansion against a constant external pressure of 1.00 atm to a final volume of 6.52 L; (b) isothermal, reversible expansion to a final volume of 6.52 L.

For part b, why can't we just substitute the nRT part of the work equation with the pressure and volume? Is it because the units don't match up?

nicolely2F
Posts: 149
Joined: Sat Sep 14, 2019 12:17 am

Re: 4B.13

Postby nicolely2F » Sun Feb 02, 2020 5:42 pm

Correct. In the ideal gas equation, the units of P.V are atm*L. But for the work equation, we need joules, which is why in nRT we use R = 8.314 J·K-1·mol-1 instead of 8.206 × 10-2 L·atm·K-1·mol-1.


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