Hey guys and girls, I wouldn't consider this a homework problem because I'm not in school. I'm just starting to prepare for next aprils GRE exam and so I was reading some thermo stuff from Daniel Schroeder's Introduction to Thermal Physics. I'm working on a problem from his book that reads: "Imagine some helium in a cylinder with an initial volume of 1 liter and an initial pressure of 1 atm. Somehow the helium is made to expand to a final volume of 3 liters, in such a way that its pressure rises in direct proportion to its volume." (So the final pressure will be 3 atm if the final volume is 3 L) so the first part of the question asks to compute the work done on the gas during the process so I just did the integral of Pdv from 1 L to 3 L and I got -4 J. But then the next part asks for the change in the helium's energy content during this process. I don't know how to do this without finding the heat added to the system and sure enough the following part asks to find the amount of heat added to or removed from the helium during the process. I think this is a simple problem and I'm just being dumb, but if anyone can point me in the right direction on how to find the head added that would be great. And this is my first post so if I happen to be in the wrong area, please let me know. Thanks for all the help.