Chemblog!

Bracing for another snow day. Okay, it's nice and all but the Regents and AP exam dates don't change so that means we have to cover the same ground in less time (yes, I said "less" for once...and it is correct here). Honors, hit the text (Chs. 13 and 15) hard and finish all of the posted worksheets (check your answers, too) if we don't have class on Tuesday.
AP (perhaps we can meet every morning from 6AM to 8AM for the next 70 days? c'mon, who has guts?)...okay, do the assigned text hw and AP Exam hw problem; I'll post several AP exam problems if we are "idle" tomorrow.
Now to make snow angels...

Just a reminder that the exam on Monday covers all of the Acid-Base notes that we have done through polyprotic acid calculations. Some of the worksheets in the 02/16/05 practice test file contain questions that we have not yet covered (buffer solutions, titrations, etc.) so don't bother doing them yet.

Notes for the upcoming week for both Honors and AP are posted . The Honors notes cover our next Math of Chem subtopic: The Gas Laws (one of the relatively easy concepts -yeah!). For the AP class, I have only revised page 6 of the previous acid-base note file so you don't have to reprint the whole blasted thing.
Looking forward to getting back to work with you all.
Mr.C.

Thanks to Emily for pointing out that Question 20 (thanks, Jenn!) had no answer choices. I updated the test file but here are the answer choices anyway:
(a) Na, Ar (b) Ar, As (c) As, Rb (d) Na, Rb

Also, on Question 24: there is a table of atomic radii in your reference tables. Read the text to see the three ways that atomic radii may be measured. Furthermore, the answer choices are given are in picometers AND they do not match the data in our reference tables so, here are the updated answer choices to that question:
(a) 1.04 A (b) 2.08 A (c) 2.54 A (d) 3.12 A

one A is 10 ^ -10 meters ( a tenth of a billionth of a meter )
one pm is 10 ^ -12 meters ( one trillionth of a meter )

Hi Octet,
Today, I posted a file that contains various Acid/Base problems. The examples are categorized and the full solutions are posted therein. Also, the answers to extra problems in the file are on the last page of the file.
Notice the problem on calculating the Ka of a weak acid given the pH at equilibrium of a certain concentration of the weak acid. We did not explicitly do a problem like this in class but, as long as you set up the ICE table properly (and understand what goes where within an ICE table), the problem is even easier than a typical weak acid pH calculation. Anyway, you've already done some Ka calculation problems already if you have been studying and doing the practice tests.
See you Monday.

Dear Octet,
I recently (2/11 and 2/18) posted some PowerPoints on our current Acid/Base/Equilibrium Unit. They are really good tutorials because they walk you through, step-by-step (click-by-click), each type of problem or explanation. Give them a look before the next test ( which is on the day of our return from vacation, good times). The test will cover acids/bases notes/hw/assignments/objectives up to and including our notes on polyprotic acids.

Dear Honors Students,
Have a happy and safe vacation; don't forget your chemistry. Do the comprehensive take home test (give yourself about 4 hours over two days to complete it; if you take much longer, you have a lot of reviewing to do) and also the Orange review book work (answers already posted for instant feedback).
Good thing that I have a blog now: If you forgot to pick up (I forgot to place them on the bench for B period, sorry) a scantron for your winter break test, just grab one on the Monday that we return to class and fill it out that day/night; the assignment is not due till Tuesday, March 1.
Thank you all for being part of such a good class- soon to be a great class- and I look forward to a successful remainder of the year with you. I know that this class is "challenging" but you will have been well-educated when all is done and I hope that you see the value of having a significant basic knowledge of chemistry.
Mr.C.

To my dear students (soon to be dear, dear, dear students with a stellar third quarter performance),
I am setting up this chemblog that is linked to our website because I often think my best thoughts in the wee hours (just before I rapidly drift off). Instead of sending a mass email (some call it "spam") that may not reach its destinations, I can simply post insights or rants in this li'l blog-space.
I know that we will enhance our chem-ablilities as a result of this link.
You are free to reply to my posts on this blog. Just make sure that your reply is pithy, germane, and properly spelled (this is not a chatroom).
Cheers,
Mr.C.