Saturday, September 22, 2007
Only 9 weeks (+10 +10) of pchem left!
So far in pchem: We finally met each other and went through the syllabus (including thursday exams and face the query). We discussed systems [open, closed, isolated], variables [intensive and extensive], equilibrium, SI units and equations of state.
The second lecture focused on the four assumptions of the ideal gas law. This led us into the van der Waals equation, which attempts to correct for nonzero volume and intermolecular attractive forces, briefly introduced in Chapter 1.5 and further developed in Chapter 7.
Isotherms and partial derivatives were the main topics in Lecture 3, particularly in correlating real gas equations of state (which are largely empirical) to observable parameters like the critical point. Figure 7.2 is a clearer example of real gas isotherms than what I chickenscratched on the board. It was pointed out to me after class that I was missing a 2 in that derivation so be sure to work through it yourself (no peeking at Example Problem 7.1).
To get a better feel for critical points, visit Table 7.2 in Appendix A for values, Wikipedia for a general background, while Table 7.4 across the page has a bunch of real gas parameters. If you want more information on partial derivatives you can either visit Appendix B.6 or, again, Wikipedia.
If you are feeling rusty in your maths, I highly recommend this book by Barrante. It basically distills down an 800-page calculus book to a paperback full of parts useful in pchem.
For this coming week we will examine the compression factor and the law of corresponding states then dive right into thermodynamics proper. To placate you, I have posted solutions to hw.zero and have updated the schedule with quiz dates.