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Why do chemistry texts write the first law of thermodynamics as ΔU=Q+W?

Answer 1

Sebastian Acosta

According to the definition:

#Delta U = Q_("in") - W_("done by")#

#Delta U = Q_("in") + W_("done on")#

Chemistry textbooks tend to favor the second one more.

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Answer 2

Isabella Alvarez

Chemistry texts write the first law of thermodynamics as ΔU = Q + W because it expresses the conservation of energy in a system. ΔU represents the change in internal energy of the system, Q represents the heat transferred to or from the system, and W represents the work done on or by the system. This equation reflects the principle that the total energy of a closed system remains constant, with any change in internal energy being the sum of heat transferred and work done on the system.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.