1. Feb 15, 2007

bio87

Hi people!
So i have a homework question that i am stuck on!!

Four moles of an ideal monatomic gas undergoes an adiabatic expansion from intial volume of 1m cubed and a temperature of 300k to a final volume of 10m cubed. a) How much wrk is done by the gas ? b) what is the final temperature? c) If instead the gas expands isothermally to 10m cubed, how much work is done? d) In part C where does the energy come from to perform the work? ...thats a lot!

I thought of using the equation of work W(by)= 1/(1-gamma) x (PfVf-PiVi) to fnd the answer for a...but I don't have the pressure.. then i thought that maybe I could use deltaE= Q(in) - W (by)...but I don't know the change in temperature, therefore; im all over the place and I don't know where to start.. any hints/help would be appreciated! Thanks

2. Feb 15, 2007

hage567

With the information you were given, you can find the initial pressure of the gas.

3. Feb 15, 2007

Andrew Mason

First work out the initial pressure, which is easy since you are given n,Ti and Vi.
What is the relationship between P and V in an adiabatic expansion/compression? (hint: it involves $\gamma$). That will give you the final pressure and, if you know n, Vf and Pf you can determine Tf.

AM