I've just transferred to a new university where they did certain aspects of thermodynamics in their first year, which is a problem because I didn't do any in my first year at the university I was previously at. I did some bits in high school but not to a very high level, so I understand the overall concept of what's going on, but am a little unsure/rusty on some things. 1. The problem statement, all variables and given/known data A) Why is the ideal gas equation a better approximation for an argon gas than for a xenon gas at the same temperature and density? [2 marks] B) i) A sample of argon expands reversibly and adiabatically to twice its initial volume. Calculate the final pressure of the gas. [3 marks] B) ii) Calculate the final temperature of the gas if the initial temperature is 25°C. [3 marks] 2. Relevant equations PV=nRT 3. The attempt at a solution A) I wrote that argon is better suited to the ideal gas equation because it as an overall smaller molecule, hence the ideal gas law holds for longer before issues such as van der Waals forces come into play, and there is less problem regarding the actual space the atoms take up, since the ideal gas law assumes the atoms take up no space at all. Hence the smaller argon atoms are better suited. B) i) PV=nRT P = nRT/V So when volume doubles to 2V, we have: P = nRT/2V I feel there's more to this, but I don't know what... B) ii) This is the bit I'm a little confused on. It's a quasistatic, adiabatic expansion, meaning no heat enters the system. All the energy goes as work, dQ = dW So is there a change in temperature? Part of me wants to say it stays the same, but another part feels like I should be doing more manipulation of PV=nRT Thanks!