# Top-rated ScreenCasts

Text Section | Link to original post | Rating (out of 100) | Number of votes | Copy of rated post |
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09.05 - Fugacity and Fugacity Coefficient | Click here. | 100 | 1 |
In a contest for "the most hated word in Chemical Engineering," Comprehension Questions: 1.What is the fugacity of a vapor phase component in a mixture according to Raoult's law? |

11.02 - Calculations with Activity Coefficients | Click here. | 100 | 3 |
Bubble Temperature (2:43) (msu.edu) The culmination of the activity coefficient method is application of the fitted activity coefficients to extrapolate from limited experiments in a Stage III calculation. The bubble temperature is the easiest after bubble pressure. The recommended order of study is 1) Bubble Pressure; 2) Bubble Temperature; 3) Dew Pressure; 4) Dew Temperature. Note that an entire Txy diagram can be generated with bubble temperature calculations; no dew calculations are required. |

12.04 - The Flory-Huggins Model | Click here. | 100 | 2 |
The Flory and Flory-Huggins Models (7:05) (msu.edu) Flory recognized the importance of molecular size on entropy, and the Flory equation is an important building block for many equations in Chapter 13. Flory introduced the importance of free volume. The Flory-Huggins model combines the Flory equation with the Scatchard-Hildebrand model using the degree of polymerization and the parameter χ. The Flory-Huggins model is used widely in the polymer industry. Comprehension Questions: Assume δ for polystyrene, where _{S}δ is the solubility parameter for styrene. Also, polystyrene typically has a molecular weight of about 15,000. Room temperature is 25°C._{S}1. Estimate the infinite dilution activity coefficient of styrene in polystyrene. |

10.07 - Nonideal Systems | Click here. | 100 | 1 |
This screencast shows how to quickly visualize Pxy phase diagrams for nonideal systems using Excel (5min, uakron.edu). These A_{12}*x_{1}*x_{2}. Rigors of this model are discussed in Chapter 11. Nevertheless, its basic elements are simple enough that they can be understood in Chapter 10. When x1=0 or x2=0, a pure fluid is indicated, corresponding to no mixing and zero heat of mixing. When A12=0, the ideal solution approximation is recovered. When A12>0, the model indicates an endothermic interaction (like 2-propanol+water, Fig. 10.8c), giving rise to "positive deviations from Raoult's Law." When A12<0, the model indicates an exothermic interaction (like acetone+chloroform, Fig. 10.9c), giving rise to "negative deviations from Raoult's Law." With this spreadsheet, you can quickly change your components and A12 values to see how the phase diagram changes and gain "hands-on" familiarity with the principles discussed in Section 10.7. Note: This is a companion file in a series. You may wish to choose your own order for viewing them. For example, you should implement the first three videos before implementing this one. Also, you might like to see how to quickly visualize the Txy analog of the Pxy phase diagram. If you see a phase diagram like the ones in section 11.8, you might want to learn about LLE phase diagrams. The links on the software tutorial present a summary of the techniques to be implemented throughout Unit3 in a quick access format that is more compact than what is presented elsewhere. Some students may find it helpful to refer to this compact list when they find themselves "not being able to find the forest because of all the trees." Comprehension Questions: |

10.01 - Introduction to Phase Diagrams | Click here. | 96 | 5 |
Introduction to Phase Behavior (9:37) (msu.edu) Comprehension Questions: 1. Referring to the Txy diagram on slide 3, estimate T, nature (ie. L,V, V+L, L+L), composition(s), and amount of the phase(s) for points: a, b. d, g. |

11.02 - Calculations with Activity Coefficients | Click here. | 96 | 5 |
Dew Temperature (7:57) (msu.edu) The culmination of the activity coefficient method is application of the fitted activity coefficients to extrapolate from limited experiments in a Stage III calculation. The recommended order of study is 1) Bubble Pressure; 2) Bubble Temperature; 3) Dew Pressure; 4) Dew Temperature. Note that an entire Txy diagram can be generated with bubble temperature calculations; no dew calculations are required. However, many applications require dew calculations, so they cannot be avoided. The dew calculations are more complicated than bubble calculations, because the liquid activity coefficients are not known until the unknown liquid mole fractions are found. This screencast describes the procedure and how to implement the method in Matlab or Excel. |

14.10 Solid-liquid Equilibria | Click here. | 93.3333 | 3 |
SLE using Excel with the M1 model (7min, uakron.edu)
Similar to LLE in Excel, the iteration feature can be used to quickly solve for SLE at multiple temperatures.
Comprehension Questions: |

07.09 -The Molecular Basis of Equations of State: Concepts and Notation | Click here. | 93.3333 | 3 |
Nature of Molecular Interactions - Macro To Nano(8min). (uakron.edu) Instead of matching the critical point, we can use experimental data for density vs. temperature from NIST as a means of characterizing the attractive energy and repulsive volume. A plot of compressibility factor vs. reciprocal temperature exhibits fairly linear behavior in the liquid region. Matching the slope and intercept of this line characterizes two parameters. This characterization may be even more useful than using the critical point if you are more interested in liquid densities than the critical point. In a similar manner, you could derive an EOS based on square-well (SW) simulations and use the SW EOS to match the NIST data(11min), as shown in this |

07.06 Solving The Cubic EOS for Z | Click here. | 93.3333 | 3 |
1. Peng-Robinson PVT Properties - Excel (3:30) (msu.edu) Introduction to PVT calculations using the Peng-Robinson workbook Preos.xlsx. Includes hints on changing the fluid and determining stable roots. Comprehension Questions: 1. At 180K, what value of pressure gives you the minimum value for Z of methane? Hint: don't call solver. 2. At 30 bar, what value of pressure gives Z=0.95 for methane? 3. Compute the molar volume(s) (cm |

09.08 - Calculation of Fugacity (Liquids) | Click here. | 90 | 2 |
Liquid fugacity relative to vapor fugacity. (LearnChemE, 5 min) This screencast shows a ^{3}/mol.Comprehension Questions: 1. How much did raising the pressure to 60 bar change the liquid fugacity (bars) (+/- 1%)? ^{3}/mol, estimate the fugacity of liquid n-pentane at 460K and 600bar.5. Compare your answers for 3 and 4 to the PREOS. |