## 4C.3 7th edition- calculate final temperature and change in enthaply

$\Delta U=q+w$

Hailey Boehm 2H
Posts: 71
Joined: Fri Sep 28, 2018 12:24 am

### 4C.3 7th edition- calculate final temperature and change in enthaply

4C.3 in the 7th edition states,
Calculate the final temperature and the change in internal energy when 765.J of energy is transferred as heat to 0.820 mol Kr(g) at 298K and 1.00 atm at
(a) constant volume
(b) constant pressure. Treat the gas as ideal.
I don't understand how to approach this problem. I think we need to use qp=nCpdeltaT, but other than that I am not sure what to do. Also, what is the significance of treating the gas as ideal?

ChathuriGunasekera1D
Posts: 78
Joined: Fri Sep 28, 2018 12:17 am

### Re: 4C.3 7th edition- calculate final temperature and change in enthaply

Hi! Yeah you're right you have to use qp = nCpdT but you also have to use Cp = (5/2) R. This comes from the equation and we didn't really cover it in class but it's what you use for a constant pressure situation. Calling the gas ideal allows us to use this specific heat capacity value.