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]
16 J/K
ΔSsystem = nRlnp1p2 = 10 × 8ln21 = 56J/K
ΔSsurrounding = −qT
ΔU = q + w, −w = Pext(V2 − V1)
q − Pext(nRTp2 − nRTp1) = nRT(Pextp2 − Pextp1)
= 10 × 8 × T(1 − 12)
ΔSsurrounding = −−qT ⇒ −40J;
ΔSsystem + ΔSsurr = 56 − 40 ⇒ 16J/K