What do the signs in the 1st Law of Thermodynamics mean?

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SUMMARY

The discussion centers on the 1st Law of Thermodynamics, specifically the equation dU = ∂Q + ∂W and its alternative form dU = Tds - pdv. The confusion arises from the interpretation of the signs in these equations. The positive sign in ∂Q indicates heat added to the system, while the negative sign in -pdv reflects work done by the system when it expands. Understanding these signs is crucial for accurately applying thermodynamic principles in various scenarios.

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mkbh_10
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From the 1st law of thermodynamics we have

dU = ∂Q+∂W

but we also know

dU = Tds - pdv ,

i am confused about the + & - sign ?

Is it because volume & pressure are inversely dependent on each other
 
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