Question

An ideal mono atomic gas at 300k expands suddenly to twice it's volume find final temperature

Answer 1

For an ideal monatomic gas ɣ = 5/3. Given initial temperature T = 300 K. Let the Initial volume  be V. Final volume = 2V. For a momatomic gas undergoing adiabatic changes, we have TVɣ−1 = constant. So TiViɣ−1 = TfVfɣ−1 .     300 V5/3 - 1 =   Tf(2V)5/3 - 1300 V2/3 =   Tf(2V)2/3 300 V2/3 =   Tf22/3 V2/3 ⇒  Tf = 300/22/3 K          = 300/1.59          = 188.7 K So answer is 189 K.