### 6th edition 9.11

Posted:

**Thu Feb 14, 2019 11:59 am**Calculate the change in entropy when the pressure of 1.50 mol Ne(g) is decreased isothermally from 15.0 atm to 0.500 atm. Assume ideal behavior.

I got the right answer for this problem using ΔS=nRln(P1/P2) = ΔS=(1mol)(8.314 J/k*mol)ln(15.0atm/0.500atm) = 42.2J/K but I'm confused how the units cancel because the R constant that I used is J/K*mol that is not L*atm/K*mol even though the pressure is using atmospheres.

I got the right answer for this problem using ΔS=nRln(P1/P2) = ΔS=(1mol)(8.314 J/k*mol)ln(15.0atm/0.500atm) = 42.2J/K but I'm confused how the units cancel because the R constant that I used is J/K*mol that is not L*atm/K*mol even though the pressure is using atmospheres.