# Calculate the final temperature and volume

1. May 13, 2007

### kingyof2thejring

1. The problem statement, all variables and given/known data
One mole of a perfect gas with molar heat capacity at constant volume, CV = 20.8 J K-1mole-1 is initially at 310 K and 3.25 x 105 Pa. It then expands adiabatically until it reaches a pressure of 2.50 x 105 Pa.
Calculate the final temperature and volume, and the work done.

2. Relevant equations
U(internal energy)=3/2RT
pV=RT

3. The attempt at a solution
to get the initial V do i use pV=RT?
Is work done = internal energy in an adiabatic process WD=3/2RT?

Last edited: May 13, 2007
2. May 13, 2007

### Dick

If the system exchanges no heat energy with it's surroundings, then how could your conclusion be wrong?

3. May 14, 2007

### Andrew Mason

2. Relevant equations
U(internal energy)=3/2RT
U = nC_vT = (3n/2)RT
pV=nRT

You have to use n: PV = nRT and W = 3n/2 RT

AM

4. Jul 30, 2007

### karthikmece

Is there any one who can help me in this regard...this is the first message i am posting in this forum

I want to calculate internal energy of an ideal gas. Are there any formulae for that or is there any method to calculate internal energy.

Thanks in advance if any one can help me in this regard.

5. Jul 30, 2007

### Dick

If you are going to ask a new question - start a new thread. But, yes, there is a formula for internal energy of an ideal gas. Look it up. Or just look at the preceding posts...