What is the entropy change in 2 mol N2 when its temperature is taken from 400 K to 800 K, at constant pressure?
ΔS=nCPlnT2T1 Cv (for diatomic) =52R Cp=Cv+R CP=72R ∴ ΔS=2×72R×ln800400=40.33≈40 J/K
Pressure of 10 moles of an ideal gas is changed from 2 atm to 1 atm against constant external pressure without change in temperature. If surrounding temperature (300 K) and pressure (1 atm) always remains constant then calculate total entropy change (ΔSsystem + ΔSsurrounding) for given process. [Given: ℓn2 = 0.70 amd R=8.0 J/mol/K]