HW8, problem 44

Normally I have a demonstration that I do in class where I freeze supercooled water; however, because the classroom is so far from my office fridge, the water won't make it without freezing or heating too much.

But if you want to see the demonstration, stop by my office at office hours or if the door is open and I'll show you it.

Youtube also has tons of videos of this, and you can easily do it at home. You just need to find really pure bottled water.

MSS

Ideal gas entropy

Hi class-

If you are interested in seeing the full treatment of the ideal gas entropy starting with Boltzmann's equation (S = k ln Omega) that includes kinetic energies, there is a short, two-page derivation in my graduate course that is at the level you should be able to understand. To read it, follow this link and go to page 14.

Have a good weekend,
MSS

Typo on Problem Set #6

Hi Class,
There's a typo on Problem 32. The second reaction is:
CO + H2O --> CO2 + H2
(the coefficient in front of H2 should be 1 instead of 3).
-Avi

Office Hours on President's Day

Hi Class,
While it's a holiday tomorrow, I'll be at school tomorrow, and hence, I intend to hold office hours. So, if you have questions about the problem set, stop by between 4-5 pm (if I'm not in 3301, I'm in my office). In any case, there will also be office hours on Tuesday as usual.
-Avi

Midterm exam notes

Hi class-

I realized that I swapped your midterm and the midterm without bonus numbers on your mid-quarter progress sheets. The higher of the two is the midterm with the bonus points included. In general, the bonus points didn't really shift the course distribution.

The letter grade ranges listed at the bottom of the sheet are highly approximate, and perhaps slightly more stringent than what will likely be the case. Here are some statistics from last year's course:

A > 79% (6 students)
B > 71% (21)
C > 57% (19)
D > 53% (4)
F < 53% (3)

Keep in mind that these grade ranges factor in the final, which is 45% of your grade. The average on the final last year was 63% with a standard deviation of 16%.

Ultimately, in assigning letter grades, we tend to look for natural breaks in the score distribution, but we also take into account the class performance as a whole relative to previous years.

Please do see me if you have questions about the midterm or the material this far. It is very important that you have a good understanding of all of the material up to this point, as we will only build on it in class.

MSS

Hi Class,
I realized I made a slight mistake on Wednesday in my solution for #1. That mistake gave me a total positive work (while it should be negative for such a cycle). The root of the mistake was that I took V1 to be the experimentally observed critical volume rather than the theoretical (van der Waals) critical volume. Thus, the equation of state was violated at the critical point, and an erroneous process was obtained. I made the corresponding corrections in the solution (it should be posted later today).
-Avi

Midterm Exam

Hi class,

The midterm will be this coming Monday in class. It will be open book and you are allowed to bring one letter size page of handwritten notes, front and back. Please bring your calculators. The test will last 50 minutes.

Avi will hold a review session at 3pm on this Sunday in room 3301 in Engineering II. This will not be a planned lecture or problem session but a time that you can ask questions about the course material or study sheet.

Cheers,
MSS