# Homework Help: What are the final pressure for the gas?

1. Dec 2, 2008

### itryphysics

1. The problem statement, all variables and given/known data
A 1.00-mol sample of an ideal diatomic gas, originally at 1.00 atm and 15 celcius, expands adiabatically to 2.00 times its initial volume.

What are the final pressure for the gas? (Assume no molecular vibration.)
What are the final temperature for the gas?

2. Relevant equations

lnP + gamma lnV = constant

3. The attempt at a solution

I dont know how to use this equation and its the only one given in the adiabatic expansion section of my book. Can someone please guide me through. Thanks!

2. Dec 3, 2008

3. Dec 3, 2008

### itryphysics

I was able to solve for the final pressure. can you please show me how to find the final temperature. Thanks!

4. Dec 3, 2008

### Confundo

Just use the ideal gas equation again. You've know $$V_2 = 2V_1$$

Last edited: Dec 3, 2008
5. Dec 3, 2008

### itryphysics

but the no numerical value for volume is given...

6. Dec 3, 2008

### Confundo

Use the ideal gas equation to find $$V_1$$