# Top-rated ScreenCasts

Text Section | Link to original post | Rating (out of 100) | Number of votes | Copy of rated post |
---|---|---|---|---|

04.09 Turbine calculations | Click here. | 90 | 2 |
General procedure to solve for steam turbine efficiency. (LearnChemE.com, 5min) This video outlines the procedure without actually solving any specific problem. It shows how inefficiency affects the T-S diagram and how to compute the actual temperature at the turbine outlet. |

14.10 Solid-liquid Equilibria | Click here. | 90 | 4 |
Solid-Liquid Equilibria using Matlab (7:17) (msu.edu) The strategy for solving SLE is discussed and an example generating a couple points from Figure 14.12 of the text are performed. Most of the concepts are not unique to UNIFAC or MATLAB. |

12.03 - Scatchard-Hildebrand Theory | Click here. | 90 | 2 |
This video walks you through the process of transforming the M1/MAB model into the Scatchard-Hildebrand model using Excel (6min, uakron.edu) It steps systematically through the modifications to the spreadsheet to obtain each new model. You should implement the M1/MAB model before implementing this procedure. Comprehension Questions: |

08.08 - Reference States | Click here. | 90 | 2 |
Departure Functions: PREOS.xls Compressor and OVC Design (11min) (uakron.edu) Redesign the ordinary vapor compression cycle (OVC) using propane as discussed in Chapter 5, this time applying PREOS.xls instead of the chart. In this |

01.5 Real Fluids and Tabulated Properties | Click here. | 90 | 2 |
P-V and P-T diagrams (LearnChemE.com) (5:52) Describes distinctions and trends between solid, vapor, liquid, gas. |

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. |

11.02 - Calculations with Activity Coefficients | Click here. | 86 | 10 |
Dew Pressure (7:41) (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 Pxy diagram can be generated with bubble pressure 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. |

01.4 Basic Concepts | Click here. | 85 | 8 |
Molecular Nature of U and PV=RT (msu.edu) (5:04) Internal energy is the sum of molecular kinetic energy and intermolcular potential energy, which leads to the relation between internal energy and temperature for an ideal gas. Also, the ideal gas law can be derived by incoporating the relation between kinetic energy and temperature with the force due to the molecules bouncing off the walls. Comprehension question: |

04.02 The Microscopic View of Entropy | Click here. | 85 | 4 |
## Principles of Probability.This is supplemental Material from "Molecular Driving Forces, K.A. Dill, S. Bromberg", Garland Science, New York:NY, 2003, Chapter 1. See the next three screencasts. This content is useful for graduate level courses that go into more depth or for students interested in more background on probability. |

01.2 Molecular Nature of Temperature, Pressure, and Energy | Click here. | 84.4444 | 9 |
Intermolecular Potential Energy (msu.edu) (7:11) The intermolecular potential energy is distinct from the gravitational potential energy of the center of mass. Further, understanding of the potential energy relation with intermolecular force is important. Comprehension Questions: 1. Molecules A and B can be represented by the square-well potential. For molecule A, σ = 0.2 nm and ε = 30e-22 J. For molecule B, σ = 0.35 nm and ε = 20e-22 J. Sketch the potential models for the two molecules on the same pair of axes clearly indicating σ's and ε's of each species. Start your x-axis at zero and scale your drawing properly. Make molecule A a solid line and B a dashed line. Which molecule would you expect to have the higher boiling temperature? (Hint: check out Figure 1.2.) 2. The potential, u(r), represents the work of bringing two molecules together from infinite distance to distance r. So, what is the force law between two molecules according to the Lennard-Jones potential model? Hint: W=∫F*dx 3. Sketch the potential and the force between two molecules vs. dimensionless distance, r/σ, according to the Lennard-Jones potential. Considering the value of r/σ when the force is equal to zero, is it greater, equal, or less than unity? |