Difference between revisions of "PChem312 f20 w4"

From MC Chem Wiki
Jump to navigation Jump to search
 
(20 intermediate revisions by the same user not shown)
Line 22: Line 22:
 
===Wednesday, Sept 9, 2020===
 
===Wednesday, Sept 9, 2020===
 
====Sec 2.9: Comparing Work/Indicator Diagrams====
 
====Sec 2.9: Comparing Work/Indicator Diagrams====
Sorry...still drawing a bunch of diagrams to help clarify the processes...i will send email when complete.
 
  
 +
=====Irreversible Work=====
 
The following shows a ''PV diagram'', also known as an '''indicator diagram'''. The center figure is Fig. 2.7 in your text. The outside "cylinders" are my annotation to clarify the diagram. I have separated the "expansion" (irreversible, isothermal) work from the "compression" (irreversible isothermal) work.
 
The following shows a ''PV diagram'', also known as an '''indicator diagram'''. The center figure is Fig. 2.7 in your text. The outside "cylinders" are my annotation to clarify the diagram. I have separated the "expansion" (irreversible, isothermal) work from the "compression" (irreversible isothermal) work.
 +
 +
 
:[[File:PV_02_Irrev_IsoT_Exp.png|600px]]
 
:[[File:PV_02_Irrev_IsoT_Exp.png|600px]]
::Starting at an initial state (P<sub>1</sub>, V<sub>1</sub>; red dot), when we remove the weight quickly, but do not allow the system to change volume, we find ourselves in a temporary/fictitious state (P<sub>2</sub>, V<sub>1</sub>; green dot). The irreversible work is then done under P<sub>1</sub> (P<sub>1</sub> < P<sub>2</sub>) ending in the final state (P<sub>1</sub>, V<sub>2</sub>; yellow dot).
+
 
 +
 
 +
::Starting at an initial state (P<sub>1</sub>, V<sub>1</sub>; red dot), when we remove the weight quickly, but do not allow the system to change volume, we find ourselves in a temporary/fictitious/non-equilibrium state (P<sub>2</sub>, V<sub>1</sub>; green dot). The irreversible work is then done under P<sub>2</sub> (P<sub>2</sub> < P<sub>1</sub>) ending in the final state (P<sub>2</sub>, V<sub>2</sub>; yellow dot). Work was done '''''by the system''''' hence has a negative value.
 +
 
 +
 
 +
[[File:PV_03_Irrev_IsoT_Comp.png|600px]]
 +
 
 +
 
 +
::Starting at an initial state (P<sub>2</sub>, V<sub>2</sub>; green dot), when we add the weight quickly, but do not allow the system to change volume, we find ourselves in a temporary/fictitious/non-equilibrium state (P<sub>1</sub>, V<sub>2</sub>; pink dot). The irreversible work is then done under P<sub>1</sub> (P<sub>1</sub> > P<sub>2</sub>) ending in the final state (P<sub>1</sub>, V<sub>1</sub>; yellow dot). Work was done '''''on the system''''' hence has a positive value.
 +
 
 +
=====Reversible Work=====
 +
Reversible work is a bit more straight forward. There are no fictitious/non-equilibrium states. The system moves between P<sub>i</sub> V<sub>i</sub> -->P<sub>f</sub> V<sub>f</sub> along the same path.
 +
 
 +
[[File:Screen Shot 2020-09-07 at 8.31.16 AM.png|200px]]
 +
:work is equal to the red area under the curve.
 +
 
 +
[[File:PV_04_Rev_IsoT_Exp.png|600px]]
 +
 
 +
 
 +
[[File:PV_04_Rev_IsoT_Comp.png|600px]]
  
 
===Thursday, Sept 10, 2020===
 
===Thursday, Sept 10, 2020===
Line 33: Line 54:
 
::* Calibrate thermometer
 
::* Calibrate thermometer
 
::* Seal thermometer
 
::* Seal thermometer
 +
::* [https://www.youtube.com/watch?v=gwswJSkS3Fg How Its Made: Thermometer]
 +
::* tour?
 +
 +
:- [[Media:HW_Indicator_work.docx|Indicator Diagram Worksheet]]
  
 
===Friday, Sept 11, 2020===
 
===Friday, Sept 11, 2020===
 +
====Sec 2.9: Comparing Work/Indicator Diagrams====
 +
continued...

Latest revision as of 14:48, 14 September 2020

...return to Chem 312 - home

Join Zoom Lecture Meeting
Join ZOOM Lab Meeting

Monday, Sept 7, 2020

Review: The first Law of thermodynamics: ΔU = q + w

Sec 2.5: Reversible Work, continued

Screen Shot 2020-09-07 at 8.31.16 AM.png

Example Problem 2.1-like

Sec 2.6: Irreversible Work, continued

Screen Shot 2020-09-07 at 8.28.46 AM.png

Example Problem 2.2-like

Sec 2.7: Other Work

focus on electrical work, Example Prob 2.3c

Sec 2.8: State Functions and Path Functions

READ

Wednesday, Sept 9, 2020

Sec 2.9: Comparing Work/Indicator Diagrams

Irreversible Work

The following shows a PV diagram, also known as an indicator diagram. The center figure is Fig. 2.7 in your text. The outside "cylinders" are my annotation to clarify the diagram. I have separated the "expansion" (irreversible, isothermal) work from the "compression" (irreversible isothermal) work.


PV 02 Irrev IsoT Exp.png


Starting at an initial state (P1, V1; red dot), when we remove the weight quickly, but do not allow the system to change volume, we find ourselves in a temporary/fictitious/non-equilibrium state (P2, V1; green dot). The irreversible work is then done under P2 (P2 < P1) ending in the final state (P2, V2; yellow dot). Work was done by the system hence has a negative value.


PV 03 Irrev IsoT Comp.png


Starting at an initial state (P2, V2; green dot), when we add the weight quickly, but do not allow the system to change volume, we find ourselves in a temporary/fictitious/non-equilibrium state (P1, V2; pink dot). The irreversible work is then done under P1 (P1 > P2) ending in the final state (P1, V1; yellow dot). Work was done on the system hence has a positive value.
Reversible Work

Reversible work is a bit more straight forward. There are no fictitious/non-equilibrium states. The system moves between Pi Vi -->Pf Vf along the same path.

Screen Shot 2020-09-07 at 8.31.16 AM.png

work is equal to the red area under the curve.

PV 04 Rev IsoT Exp.png


PV 04 Rev IsoT Comp.png

Thursday, Sept 10, 2020

- Thermometer (cont.)
- Indicator Diagram Worksheet

Friday, Sept 11, 2020

Sec 2.9: Comparing Work/Indicator Diagrams

continued...