Holiday replacement · Independent study · 180 minutes
Consistency tests
before LLE
First ask whether activity data obey a thermodynamic constraint. Then ask whether a liquid split is stable. Work through the slides, calculations and two labs in this order.
This week has no live class because of the holiday. Keep Pause for activities enabled in the video player. Complete each task before selecting Continue to next slide. For a reading-based route, use the same lesson slides. Both routes cover the same worksheet and Labs; you do not need to complete both.
Follow the 180-minute route
Times are elapsed study time, including your work. Each slide names the worksheet section and the resource to open. Use the lab guide when you need the exact controls.
| Elapsed time | Activity | Open and record |
|---|---|---|
| 0–15 min | Review activity coefficients and evidence from Lab 08 | Slides; worksheet p. 1, A1–A3 |
| 15–35 min | Gibbs–Duhem and when a diagnostic applies | Slides; worksheet p. 1, B1–B3 |
| 35–50 min | Calculate a signed area by hand | Slides; worksheet p. 1, C1–C3; calculator |
| 50–80 min | Compare a reference, canceling errors and a local defect | Lab 03; worksheet p. 2, D1–D4; guide pp. 1–2 |
| 80–90 min | Explain why methods can disagree | Slides; worksheet p. 2, E1–E2; check your attempt |
| 90–100 min | Break | Save your work and step away from the screen |
| 100–120 min | Gibbs energy, a common tangent and the lever rule | Slides; worksheet p. 3, F1–F3 |
| 120–165 min | Change overall composition while keeping the liquid model fixed | Lab 04; worksheet p. 3, G1–G4; guide p. 3 |
| 165–172 min | Attempt the review, then check and correct | Worksheet p. 4, H1–H4; worked solutions after your attempt |
| 172–177 min | Exit ticket | Worksheet p. 4, I; Session 3 form |
| 177–180 min | Feedback and save your work | Finish the same form, wait for the receipt, keep your files |
Documents and labs
Use during the lesson
Optional support
- Three-page background reading, for reference within the lesson or further study
- Lab 08 video walkthrough, for a targeted reminder during the first 15 minutes
- Session 3 appendix
- Lab 05: LLE fitting and Lab 06: VLLE, optional extensions
- Offline package; includes slides and documents. The video is online or a separate MP4 download; the response form needs internet
What your evidence should show
- For Lab 03, record the dataset, sampling resolution, perturbation and amplitude. Compare the area and local diagnostics on the same settings, and inspect the residual plot.
- For Lab 04, keep the model and its parameter fixed while changing only the feed composition. Record the actual calculated tie-line endpoints and phase fractions, then close the material balance independently.
- Write one supported conclusion and one limitation for each lab. A small fit residual, thermodynamic consistency and stable phase equilibrium are different checks.
The hand-calculation endpoints 0.2 and 0.8 illustrate the lever rule. They are not the expected endpoints of the Lab 04 model. Use the endpoints the lab calculates for your chosen parameters.
Finish with the Session 3 exit ticket and feedback
In the concept answer, explain the additional stability evidence needed after a solver finds equal chemical potentials, and what changes when the overall composition moves within a supported tie line.
In the numerical evidence answer, include your Lab 03 area-versus-local comparison, with the dataset and settings. Add your Lab 04 balance if helpful. Report one remaining question and feedback on pace and access.
Wait for “Response received.” This anonymous form does not identify attendance. Keep the worksheet and lab exports together; use any submission arrangements announced by the instructor.
