Calculating Maximum Work from Cooling Liquid Reversibly

AI Thread Summary
The discussion revolves around calculating the maximum work obtainable from cooling a liquid reversibly, given its constant molar heat capacity and initial temperature. The participant struggles to understand the concept of maximum work, initially believing it to be equal to the total heat released, which is 7260 J. However, the provided answer is 601 J, leading to confusion about the calculation process. The first law of thermodynamics is referenced, indicating that maximum work occurs when the system is insulated, implying that Wmax equals the change in internal energy. The participant seeks clarification on how the answer of 601 J was derived, highlighting a gap in understanding the relationship between heat transfer and work in reversible processes.
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Homework Statement



One mole of a liquid with a constant molar heat capacity of 132 j/mol K is initially at a temp of 80 C. The heat capacity is independent of tempearture. Calculate the maximum work that could have been done onthe surroundings while cooling the liquid reversibly. The surroundings are at a temp of 25 C.


Homework Equations



Given: q= -7260 J , change in entropy= 22.3J/K for the cooling

Change entropy = (Cvdt)/T



The Attempt at a Solution



I guess my problem here is not understanding what maximum work is, i would think that the maximum work here is in a reversible process would be the total amount of heat that is released that has the potential to do work, so wouldnt' that b 7260 J? The answer provided is 601 J

thanks guys
 
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I'm not sure this is helpful because I don't see how the answer of 601 J was arrived at, but from first law ΔU=Q-W where ΔU=n∫Cv*dt. For a liquid Cv≈Cp but Cp is constant therefore ΔU=n*Cp*ΔT. Maximum work would occur if Q=0 (insulated container). Therefore Wmax=ΔU

Maybe I am missing something
 
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