IMG_0001_NEW_0015

IMG_0001_NEW_0015 - vJ. -v D -- -lt+,,-v,> 2)...

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TODAY'S LECTLIRE: B "Spontaneity, Entropy and Free Energy" (Chapter 10) Expansion and Compression of an Ideal Gas Reversible and Irreversible Processes Entropy and Work Calculating AS for Physical Processes 1) 2) r) 4) Revers i b le/l rreve rs i b le Processes Reversible Process: a system is changed in such a way that the system AND surroundings are restored to their original state by exactly reversing the change TEST CASE: Isothermal Expansion and Compression of an Ideal Gas Isothermal: temperature of system and surroundings remain constant at all times =AE:0 Since: LE: q +x:0 =@ mss Acceleratlon due to gravity \/ - force .Vs P..,.",= - : j Pu,",,"rocnrassinpan areQ 1 \ aea ofpiston Heat reseNoir (+ constdt T) Gompression ,- -) ----\ :llExpansion) ,t | --:----v G Ej Zfr*'*il Nt \i,n, \r-A -)1 ra l-step Expansion followed by l-step Compression l) Expansion: P, -+ Prl4 and Vt --> 4Vt v'- -P,,,LV = - (erc(
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Unformatted text preview: vJ. -v D -- -lt+,,-v,> 2) Compressionz P1l4 -+ P1 and 4V, -+ v' = - P".,,LL' =1 - Pa+ UJ -li) = - ?t \tlr+V, Net nork = guml ,ein ead, sV =-v,6ltV1- \()T ltE\ llRslBLII "One-Step" Expansion and I Step Expalsion, W 11 volume 1L Steps Extra work done Reduce mass: M, -+ Mrl4 = Reduce P"*,: P, -+ P,14 = Work - wf -}.l1Ptvl Reduce pressure in 2 steps lr,lt lr,l = Expansion work is pathway-dependent Work is not a state function 6 lwul=\r,ur, t=l lr,lr. ...]r,1r l.,l Infinite small steps in external pressure between P, and Prl4-) maximum area-) maximum work-ir, ) hV1 V,'4-- >-YgYrV vt 2\ 4/, 6 Steps Even more L workdone XA z/t ffi/ {#M J :t&L/tffiWz7l) W @ Net heat flow = t> tv)=o 9 ---v0 Multiple-Step Expansion Work lWorkl : PLV: area under graph (pink) 1/= ->'tPrv1 C lw't dea'sedS Infinite steps (done to surroundings) +...
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