Entropy chance with a carnot cycle?

AI Thread Summary
In a Carnot cycle, the gas expands adiabatically from 200 degrees to 500 degrees, resulting in an efficiency of 38.8%. During this adiabatic expansion, the entropy change of the gas is questioned. It is clarified that since the process is adiabatic, there is no heat transfer (dQ=0), leading to an entropy change (ΔS) of zero. Therefore, the understanding that the entropy remains constant during adiabatic expansion is correct. The discussion confirms the relationship between adiabatic processes and entropy.
coffeem
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in a carnot cycle the gas expands adiabatically from 200 degrees to 500 degrees. what is the efficecy? and what is the entropy change of the gas during the expansion?

sorry - i got the efficiency to be: 38.8%

however I am unsure how to work out the entropy chance? any hints?
 
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however my thinking is that if the the system is adiabatic... then the entropy will stay constant... then it will be 0? am i on the right lines? thanks
 
Hi I am still struggling with this. any advice? thanks
 
coffeem said:
however my thinking is that if the the system is adiabatic... then the entropy will stay constant... then it will be 0? am i on the right lines? thanks

If ΔS=dQ/T and dQ=0 for an adiabatic process then ΔS=0. So you are right.
 
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