Question

3. A mole of perfect Gas initially at 101 325 pa is expanded from 22.4 L at a constant pressure of 0.20 bar at a constant temperature of 273 K until it cannot expand anymore. Is this expansion spontaneous? How much heat is transferred in this process? How much has the entropy changed as a result of this process?

Answer 1

o The follaming given process is an isothermal ireversible proces o It is bothermal because the temparature is Cantant, as the I heat flanning across the wall (in othermal wall) which ineequal to the amaunt at workdane, in magnitude. VAE = a +W OS LE = n ev.lt -T). Maw AT=0) TQ --W1 --') Volume & The process iss ireversible as it in occurring in ane tep against a Cauntant external pressure. Waricdane - - Perex Cehenge) SEDx Wirra-Pext (V₂ -v1) L I Wirra-Pext (HRT ART - Pext Pin o where Pext is the final pressure ar oppasing pressure against which the expansian occurs. o where Pi is the initial pressure of the gas.

Amaunt of heat absorbed in the to the almalust at workdane, process is uivalent WE - Pext Chat - ART) Pert E-MRT (1- Dext) Placing the values al pert and Pi 5 - Ymal x 0.082 Lt celtin mal-7-x 673 k®(17 ar = 0. 20/1:0 1325 atm = 0.19738 alon [ as 1.01325 bar = lam] Pia 101325 pa = larm as I atm = 1.01325x105 Pal T= 273K nel mol WE-ART (1-Pext) R = 0.082 44 atu monika =-Imo1 x 0-082 Lt atm meal-tke -1x 273 k*(1-0-19738) aben =-17-967 Lt-aten = -11820 KJ Tas i 17-cbm = 101133] How we have E Fatw DE = niev.09 = 0 [as of = 0] :: Q=-W=- [-1820] kJ = 1.820 kJ The positive sign indicates the amount of heat abrarbed- o Change of Entropy Fram definitian of contropy AS - AUDIT

A Sirev= sqirer - 1.820x1033 273k Esiva = 6.663/k o go the process Cantiniaus The continuity at the spontanity of the process depends! aun the cos Now, by definition, G= E + PV -T5 d675dE + d (PU) – THS-5.di t67= d (E+PW) - T-45 [As dT=0] dG7 dH -7.15 LAS HE E+ PV by definition AG=AH-7.45 Now, AH = niep.OT=oras AT=o far isothermal Procus 7 -AGE-273 K x 6.663.K-! = -1.82041033 The ove sign indicates the process is spanteniaus