## Question from midterm

$\Delta U=q+w$

Grace_Stevenson_1A
Posts: 49
Joined: Wed Sep 21, 2016 2:57 pm

### Question from midterm

I am unable to go to the review on Friday, so was wondering if someone could help me with this question? Thank you!! :)
Q2: A system consists of two glass vessels (containers A and B) and a valve connection them. During the following process this system is maintained at 25 degrees C. Initially, the valve is closed. Container A (0.24L) has 2.0 mol O2. Container B (0.24L) has 8.0 mol N2. Now we open the valve and wait until the system reaches equilibrium. Consider O2 and N2 as ideal gases.

A. What is delta U,q,w, and delta H?
I understand how to find all except w. The solutions says there is no change in volume so is 0, but isn't there a change in volume from .24 to .48L when the valve is opened? How would we know that there is no change in volume. Thank you!

William Shu 1G
Posts: 18
Joined: Wed Sep 21, 2016 2:56 pm

### Re: Question from midterm

There is no change in volume of the total system. Yes, the valve is being opened inside the system, but the system is not interacting with the surroundings in any way. Also, if you use the equation q=-w after knowing q, then you could also find that w=0. Hope this helps!

Namaste246
Posts: 11
Joined: Fri Jul 15, 2016 3:00 am

### Re: Question from midterm

The question asks for the change in volume of the system. The system, as put in the question, consists of two glass vessels each with a volume of 0.24 L.