Top-rated ScreenCasts
Text Section | Link to original post | Rating (out of 100) | Number of votes | Copy of rated post |
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07.02 Corresponding States | Click here. | 100 | 2 |
Principles of Corresponding States (10:02) (msu.edu) Comprehension Questions: 1. What is the value of the reduced vapor pressure for Krypton at a reduced temperature of 0.7? How does this help us to characterize the vapor pressure curve? 2. Sketch the graph of vapor pressure vs. temperature as presented in this screencast for the compounds: Krypton and Ethanol. Be sure to label your axes completely and accurately. Draw a vertical line to indicate the condition that defines the acentric factor. |
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 sample calculations for methanol+benzene apply the simplest nonideal solution model: ΔHmix = A12*x1*x2. 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: |
07.11 - The molecular basis of equations of state: analytical theories | Click here. | 100 | 1 |
Nature of Molecular Energy - Example Calculation(8min, uakron.edu) Given an estimate for the radial distribution function (RDF) integrate to obtain an estimate of the internal energy. The result provides an alternative to the attractive term of the vdW EOS. |
09.04 - Changes in Gibbs Energy with Pressure | Click here. | 100 | 1 |
Gibbs Energy - Nuts to Soup. (learncheme.com, 8min) It is straightforward to start from the definition of Gibbs Energy and derive all the changes in Gibbs energy. These can be graphed for H2O to see how familiar quantities from the steam tables relate to changes in this unfamiliar property. |
01.5 Real Fluids and Tabulated Properties | Click here. | 100 | 2 |
Double interpolation (uakron, 8min) is exactly what it sounds like: to find a steam property when neither the pressure nor temperature are among the tabulated values, you need to interpolate twice. We interpolate first on pressure, then on temperature. It is a bit tedious, but straightforward. Comprehension Questions: |
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. |
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. |
07.06 Solving The Cubic EOS for Z | Click here. | 95 | 4 |
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) (cm3/mol) for argon at 100K for each of the following? |
14.10 Solid-liquid Equilibria | Click here. | 95 | 4 |
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: |
04.09 Turbine calculations | Click here. | 93.3333 | 3 |
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. |