# 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.