Question

6 moles monatomic gas is compressed adiabatically to 1 8 of its initial volume. Initial temperature is 300 k. Find work done on the system

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 - 1 300 V2/3 =   Tf(2V)2/3 300 V2/3 =   Tf 22/3 V2/3 ⇒  Tf = 300/22/3 K          = 300/1.59          = 188.7 K So answer is (b) 189 K.