Adiabatic Expansion of Steam

Organized by textbook: learncheme.com/ Uses steam tables to determine the work done by the adiabatic expansion of steam. Excel spreadsheet steam tables: learncheme.com... Made by faculty at the University of Colorado Boulder, Department of Chemical and Biological Engineering. Reviewed by faculty from other academic institutions.
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[@kylecatman7738]

What if you had gone from state 2 to state 1? You end up with a negative S-total, which I thought is impossible.

[@kylecatman7738]

delta H includes boundary work people, closed systems like a piston have boundary work, or a balloon even. If it's constant pressure, use H, U is for constant volume only. But only boundary work is withing enthalpy, other work like shaft, electrical or paddle STILL have to be included in the 1st law.

[@kylecatman7738]

Here, he's asking for work so you have to separate out the work from enthalpy like he did here. H = U + PdV

[@gooddeedsleadto7499]

Beautiful explanation, I enjoyed it. Thanks again.

[@LearnChemE]

This screencast has been reviewed by faculty from other academic institutions.

[@canayaz3344]

Hey, let's say first temperature (450C) is not given, how can you find work done? please help me! thanks

[@matt66545]

Why are we using Delta U instead of Delta H?

[@UliSwag]

2:30 because it's a closed system. No mass flow in or out of the system

[@kylecatman7738]

@@UliSwag Not true, delta H is used when there's boundary work, here it's asking for the boundary work separately. But for your info delta H is internal plus boundary work. Open systems use delta H because Flow work is included in enthalpy, just like boundary work in closed systems.

[@kylecatman7738]

If you delta H minus delta U you will get the boundary work of 68