Entropy Variation - System, Neighborhood and Universe

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SUMMARY

The discussion centers on the concept of entropy variation, specifically the equation ΔSuniv = ΔSsys + ΔSneib. It establishes that a process is spontaneous if ΔSuniv > 0. John raises a question regarding the relationship between heat exchange in the system and the neighborhood, suggesting that if Qsys = -Qneib, then ΔSuniv would always equal zero. However, it is clarified that ΔS = Q/T applies only to reversible processes, while for irreversible processes, ΔS must be greater than Q/T.

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  • Basic grasp of heat transfer concepts.
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jaumzaum
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I learned ΔSuniv = ΔSsys + ΔSneib

If ΔSuniv > 0 the process is spontaneous.

But ΔS = Q/T right? Shouldn't Qsys = -Qneib? (The heat released by the system = - heat released by the neighborhood)
I cannot understand why this is wrong!

If it were the case, ΔSuniv would be always zero

Can anyone help me?

[]`s
John
 
Chemistry news on Phys.org
##\Delta S=Q/T## only for reversible processes.For irreversible processes, ##\Delta S>Q/T##.
 

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