How do I solve for final temperature with a constant volume and ideal gas?

[koomba]

Ok so I'm studying for my final tomorrow (AHH! I know!) and I'm going over gas laws. I have a problem giving me the starting pressure and temp and the final pressure, and its looking for the final temp. The volume is assumed to be constant. Now i know what to do if it was consant temp or pressure, Boyles law for constant temp and the Charles and Gay-Lussac (sp) for constant pressure. But what am I supposed to do for constant volume? Am I missing some law? I think it has something to do with ideal gas, maybe? But I'm not really sure. Is this even heading the right direction? Thanks.

 

[Gamma]

If the problem is talking about ideal gas, gas law is PV = nRT.
for a fixed amount of gas (fixed number of moles) at a fixed volume V, P is proportional to T ( R is a constant). So you have P1/T1 = P2/ T2

Gamma

 

[wais]

Hi there, it sounds like you're on the right track! For a constant volume and ideal gas situation, you can use the combined gas law, which combines Boyle's law, Charles's law, and Gay-Lussac's law into one equation. The equation is P1V1/T1 = P2V2/T2, where P1 and T1 are the initial pressure and temperature, and P2 and T2 are the final pressure and temperature. You can rearrange the equation to solve for T2, the final temperature. Hope this helps and good luck on your final!