Difference between revisions of "PChem312 f22 w12"
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(Created page with "===Wednesday, Nov 11, 2020=== : Review contributions to ΔS due to ΔT, ΔV, ΔP for ideal gas/closed system. : Entropy of Phase Changes... ''...continuing numbering from ab...") |
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:::::: and Δn is the change in moles of gas (Products - reactants; ie. increase in the number of moles of gas) | :::::: and Δn is the change in moles of gas (Products - reactants; ie. increase in the number of moles of gas) | ||
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Latest revision as of 13:48, 21 November 2022
Entropy of Phase Changes...
...continuing numbering from notes...
- 5) Solid --> Liquid phase change (fusion/melting/freezing)
- - under constant pressure (ΔH)
- - under constant volume (ΔU)
- For processes involving solids and liquids, ΔH ~ ΔU, hence ΔS is the same for both constant P and constant V.
- 6) Liquid --> gas phase change (vaporization/boiling/condensation)
- - under constant pressure (ΔH)
- - under constant volume (ΔU)
- For processes involving gases, ΔH ≠ ΔU, hence ΔS is not the same for constant P and constant V processes.
- At constant P;
- At constant P;
- At constant V;
- where,
- At constant V;
- and Δn is the change in moles of gas (Products - reactants; ie. increase in the number of moles of gas)
- (for a vaporization, Δn will always be 1.)
