A monatomic ideal gas is compressed adiabatically. What is ΔS of the gas?
n = 1.00
vi = 10.00 L
vf = 4.00 L
Constant External Pressure = 50.00 atm
ΔU = q + w = 0 + (-PextΔV)
ΔS = ∫[(qrev)/T]dQ
The Attempt at a Solution
In order to calculate ΔS you have connect two thermodynamic states with a reversible path. I assumed that the ΔS of the system is 0 because dQ is 0 for adiabatic processes). Then second state focuses on ΔS of the surroundings that has an external pressure associated with it.
I found Tf = 322.06 K by using the ΔU equation
I am not sure what to do at this point, because every single attempt I made has led me to a negative ΔS.