Keep the Heat B/Thermodynamics C

[DivineBbbbbeast]

I recently visted the Test Exchange and noticed that tests from the Athens Invitational were posted in most events, except for Thermodynamics. Does anyone have a copy of the test that they can post?

Ummm... If i recall correctly, the first few pages of the St Joe's test already online was the same as the Athens test, but the athens test also had a little bit of thermochemistry involved with it

[questionguy]

I recently visted the Test Exchange and noticed that tests from the Athens Invitational were posted in most events, except for Thermodynamics. Does anyone have a copy of the test that they can post?

Ummm... If i recall correctly, the first few pages of the St Joe's test already online was the same as the Athens test, but the athens test also had a little bit of thermochemistry involved with it

Thanks. Does anyone know how to solve this question.

- Twenty five identical molecules are in a box. Identifying the molecules in the left and right halves of the box designates microstates. The Boltzmann constant is 1.38 x 10^-23. The entropy associated with the configuration for which 15 molecules are in the left half and 10 molecules are in the right half is:

Answer: 2.07 x 10^-22 J/K

[marty3]

Hmmm, that's a pretty complicated problem for high school, I think. Anyway, here it goes.

If you want the entropy of a system, go back to the most basic definition:

S = k*ln(omega)

k = boltzmann's constant
omega = number of possible states

The particles are taken to be identical, simplifying omega to nothing more than the combinatorics problem 25 choose 15, or 25!/(15!*10!).

S = 1.38*10^-23 * ln(25!/(15!*10!)) = 2.07*10^-22 J/K

This answer only works because the box is split into 2 equal parts. Otherwise it gets more interesting, I think.

[sciencegeek999]

Is there anyone other than me that does not like the system in which they measure the heat of the internal beaker after the test?
My water temperature was measured 5 minutes late. One team's was measured 8 min late.

[Skink]

Unfortunately, unless the supervisor has probes set up to automatically record the temperatures, I don't know how else it could be done. Seems several IL competitions have had this event run questionably...at one invitational, the supervisor forgot to record the final temperature for two teams and was going to make it up by averaging the other teams'. I kid you not. They didn't get away with that for long.
On the other hand, this is a relatively difficult event to run, so kudos to anyone who has done so smoothly and successfully.

[foreverphysics]

Actually, we don't have an issue with measuring times late in AL. It seems that we do it, we get the test, and they measure the temperature after exactly the time frame, whether we're still taking the test or not. It works well, and we still finish the test--one team memeber keeps working, and the other does the temperature stuff.

[sciencegeek999]

At my invite, and regionals, there was no problem. Only at state, which I find ironic because isn't state supposed to be very accurate and organized?

[illusionist]

Concerning the "identical beakers" rule, one of our beakers has some salt stains on the outside surface that I can't wash off no matter how hard I try. It's not significant, but enough to be noticed when examining the beaker. Will this cause too much trouble at competition or be okay? (I know it all depends on the event supervisor)

[chalker]

Concerning the "identical beakers" rule, one of our beakers has some salt stains on the outside surface that I can't wash off no matter how hard I try. It's not significant, but enough to be noticed when examining the beaker. Will this cause too much trouble at competition or be okay? (I know it all depends on the event supervisor)

Have you tried some CLR or LimeAway or similar type stuff? Should get it right off.

[Wowohn]

I did keep the heat at our State Competition for Pennsylvania. It was a complete mess. They had us do this experiment we combined hot and cold water and observed it? The Everybody's water went all over and became very messy. Then when they went to heat our water they heated the beakers on the hot plate also. When we finally did get the water it was 85 degrees when other peoples was 90 and we didnt get let out till 10 minutes late so I was late for y next event. }If this sounds complainy I'm sorry but I think we really need something more standardized nest year.