1. The problem statement, all variables and given/known data The screen shot I have attached is the original question, I think I'm ok up until the Ne part. My answer just seems like a ridiculous number, I haven't had much experience with this so don't really know what an 'normal' KE for 1kg of gas would be. 2. Relevant equations 3. The attempt at a solution Hopefully it's clear what I've done. The solution to the first part (deriving and expression for the mean translational KE...) is the equation I start with, if that is wrong then please let me know. EDIT - have just realised I put the final answer as 5.49.... it should be 2.49.