Learning undergraduate engineering thermodynamics might be less painful with a blog. I hope that students, faculty and interested observers will share their thoughts on the laws of thermodynamics, phase and chemical equilibrium and many related topics.
Please post any questions or discussion related to this problem as comments on this message. Feel free to answer other students' questions. I will check the blog M-F and once on the weekend. Dr. B
Hey Dr. B I am having a really hard time figuring out when I'm supposed to look up data and when I'm not, what models to use, and which sources to choose. I'm getting so caught up in all these numbers that I'm losing track of the concepts. Help!
MagicMarker: I can understand how you can lose sight of the important concepts here. On problems 1 & 2, I wanted you to learn to use NIST or the TFT plug-in to look up data in the thermodynamic property tables. The catch is that these COMPLETE thermodynamic data tables only exist for a few chemicals...about 50. What do you do for OTHER chemicals ? Check out problems 3 - 6. In problems 3 - 6, I want you to use data also from NIST (but NOT from the complete thermodynamic tables) to ESTIMATE properties or changes in properties. You estimated DU and DH ( in p3 and P4) using Shomate. In P5 & P6, you estimated DHvap using Clapeyron and Clausius-Clapeyron. In the real world, use the BEST available data source. But you cannot count on always having complete thermodynamic data tables. These 50 chemicals are the EXCEPTIONS, not the norm.
Questioning: There was no quiz 8 because there was no reading assignment for class #8 (last Friday). We had a problem session. We will not have quizzes whenever we have problem sessions.
4 comments:
Hey Dr. B
I am having a really hard time figuring out when I'm supposed to look up data and when I'm not, what models to use, and which sources to choose. I'm getting so caught up in all these numbers that I'm losing track of the concepts. Help!
MagicMarker:
I can understand how you can lose sight of the important concepts here.
On problems 1 & 2, I wanted you to learn to use NIST or the TFT plug-in to look up data in the thermodynamic property tables.
The catch is that these COMPLETE thermodynamic data tables only exist for a few chemicals...about 50. What do you do for OTHER chemicals ? Check out problems 3 - 6.
In problems 3 - 6, I want you to use data also from NIST (but NOT from the complete thermodynamic tables) to ESTIMATE properties or changes in properties.
You estimated DU and DH ( in p3 and P4) using Shomate. In P5 & P6, you estimated DHvap using Clapeyron and Clausius-Clapeyron.
In the real world, use the BEST available data source. But you cannot count on always having complete thermodynamic data tables. These 50 chemicals are the EXCEPTIONS, not the norm.
I hope this helps a bit.
why was there not a quiz 8, or was there and did i miss it?
Questioning:
There was no quiz 8 because there was no reading assignment for class #8 (last Friday). We had a problem session. We will not have quizzes whenever we have problem sessions.
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