## Exercise 8.31

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

### Exercise 8.31

Can someone explain how to do the constant pressure and volume question?
8.31 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.
I'm really confused with these constant values now since the topic I familiar with is just specific heat capacity.

Thanks!

Chem_Mod
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Joined: Thu Aug 04, 2011 1:53 pm
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### Re: Exercise 8.31

The equation used for calculating heat released is q=mCΔT. Since we are told that Kr behaves as an ideal gas, we can use the specific heat capacity for ideal gases at constant pressure (Cp=5/2R) and at constant volume (Cv=3/2R).

torialmquist1F
Posts: 49
Joined: Sat Jul 22, 2017 3:00 am

### Re: Exercise 8.31

Chem_Mod wrote:The equation used for calculating heat released is q=mCΔT. Since we are told that Kr behaves as an ideal gas, we can use the specific heat capacity for ideal gases at constant pressure (Cp=5/2R) and at constant volume (Cv=3/2R).

Where does the 5/2R come from?

Lourick Bustamante 1B
Posts: 50
Joined: Wed Nov 16, 2016 3:02 am

### Re: Exercise 8.31

It's a given! It's explained in Chapter 8.10 of the textbook! (: