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work in enthalpy vs. internal energy
Amna_5729
#1 Posted : Tuesday, July 28, 2020 1:41:23 AM
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ΔH = ΔE + Δ(PV) & ΔE = q + w

What is the difference between the work in the internal energy equation and the work (Δ PV) in the enthalpy equation?

INSTR_Katerina_102
#2 Posted : Tuesday, July 28, 2020 6:51:37 AM
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Hi Anna,

"ΔH = ΔE + Δ(PV) & ΔE = q + w

What is the difference between the work in the internal energy equation and the work (Δ PV) in the enthalpy equation?
"

d(PV) is distinct from w in that work = -PdV

When you have d(PV) instead of PdV, the implication is that it is a change in either P or V. As a result, we cannot say that it is work for sure as you could have a constant volume and an increase in pressure.

However, when P is constant, we can have

d(PV) = PdV at constant P

And therefore

PdV = -w

Please let me know if this is unclear!

Katt
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