8.31

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Virpal Gill 1B
Posts: 32
Joined: Thu Jul 27, 2017 3:00 am

8.31

Postby Virpal Gill 1B » Sun Feb 11, 2018 9:24 pm

The question is: "Calculate the heat released by 5.025 g of Kr(g) at 0.400 atm as it cools from 97.6 C to 25.0 C at (a) constant pressure and (b) constant volume. Assume that krypton behaves as an ideal gas." The answer for constant pressure is -90.6 J and the answer for constant volume is -54.4 J. Why is more heat released at constant pressure than at constant volume? I thought some of the heat released at constant pressure is needed to do work.

Jaewoo Jo 2L
Posts: 31
Joined: Fri Sep 29, 2017 7:06 am

Re: 8.31

Postby Jaewoo Jo 2L » Sun Feb 11, 2018 9:34 pm

More heat is released at constant pressure because the volume gets smaller as well as the temp getting lower, requiring extra work. if the volume is constant, than only the temperature is going down, releasing less heat.


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