Homework Help: Physics degrees of freedom problem

1. May 27, 2005

squib

A 1.12 mol sample of an ideal diatomic gas at a pressure of 1.00 atm and temperature of 491 K undergoes a process in which its pressure increases linearly with temperature. The final temperature and pressure are 735 K and 1.39 atm. Assume 5 active degrees of freedom.

Neither pressure nor volume nor temp are constant, so I'm confused to how I'm supposed to find work or q.

2. May 27, 2005

Corneo

Have you seen this formula before?

$$\Delta Q = \Delta U \pm W$$, the $$\pm$$ is there depending on how you define when is work positive. If I recall correctly $U = \frac {q}{2} n R T$ where $q$ is the numbers of degree of freedom.

3. May 27, 2005

OlderDan

A couple of things you need to key on. What is the connection between degrees of freedom and heat capacity? And what can you do with the fact that the P vs T curve is linear?

4. May 27, 2005

squib

I assume I could graph P vs V and find work, but that seems like more work then should be neccesary. I can find the change in U, or overall energy of the system, the only problem I'm having is with work, which should give me heat since I know U.