# Internal Energy vs Pressure

1. Oct 25, 2012

### ab94

1. The problem statement, all variables and given/known data
For example in the problem if we have a volume of 10L at 15 degrees Celsius, and there is initially 100Pascals pressure, what would the final pressure be if we double the Internal Energy?

2. Relevant equations
U=3/2nRT

3. The attempt at a solution
I though pressure was independent of Internal Energy so it would remain unchanged? but Idk

2. Oct 26, 2012

### haruspex

If you change the volume, and hence the pressure, isothermally then the internal energy will not change. But if the volume stays the same then pressure and temperature can only vary if the other does too. Here, internal energy is being increased, so the temperature is going up, but the volume stays the same. So what happens to the pressure?

3. Oct 26, 2012

### ab94

The pressure would also double?

4. Oct 26, 2012

### Andrew Mason

It depends. Is this an ideal gas? Can you explain your answer in terms of the ideal gas law?

AM