## Textbook Question

$\Delta U=q+w$

Riya Shah 4H
Posts: 65
Joined: Wed May 02, 2018 3:00 am

### Textbook Question

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.

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Joined: Fri Sep 28, 2018 12:28 am
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### Re: Textbook Question

So for this problem you're gonna wanna use the ideal gas equations, Cp (constant pressure) is 5/2 of the gas constant (which is 8.314) and Cv (constant volume) 3/2 of the same gas constant. One you calculate the C for each scenario you'll plug it into equation nCdeltaT to solve for q which is the heat released.

For example,
Cp = 5/3(8.314) = 20.875
5.025 g Kr/83.798 g/mol = .05997 moles Kr
q=(.05997)(20.785)(25.0-97.6) = -90.5 J

Then you'll just do the same thing for Cv all that changes is the heat capacity

Hope this helps:)