Chemblog!

Chemistry Regents Review must be a daily habit until June 21. Thus, we have two more actual released exams posted on the website. As I explained in class, take the Regents properly: go over the past two exams that we started to review today, then take the new exams (one every other day). Carefully mark up each question, write any formula, definition, illustration, explanation, etc. to show how you predicted your answer to each question. I added the answer keys to the file; the intelligent student will only review the key AFTER s/he has completed the test. Again, your part B-2 and C answers should be more elaborate and Honors-level than the succinct, "Frankenstein"-talk answers on the key. I will collect and grade your work; those two tests are due IN CLASS on Tuesday.

I posted a detailed Reference Table that you should practice copying so that you can commit the information to memory for test-day. Please let me know if you think of any mnemonics to add to the table. I also posted the current NY State Chem Regents Syllabus upon which all Regents questions are based.

Our Nuclear/Organic written exam will be next Thursday. Make sure that all of your review worksheets/hw is done by then.

Random most frequently asked question: What does AMPHOTERIC/AMPHIPROTIC mean? an AMPHOTERIC/AMPHIPROTIC substance can act as either a Bronsted acid = H+ donor/proton donor or as a Bronsted base = H+ acceptor/proton acceptor in a chemical reaction.
For example:
rxn 1 HS- + H2O --> H2S + OH-
rxn 2 HS- + NH2- --> S 2- + NH3

in rxn 1, HS- is acting as a proton/H+ acceptor i.e. a Bronsted base
in rxn 2, HS- is acting as a proton/H+ donor i.e. a Bronsted acid.

I will post another Regents by Monday; just download that one and PREVIEW/HIGHLIGHT some questions that you want answered during Tuesday's class. If ANYONE is not ready for review on Tuesday, s/he will be given an in-class 100-point exam immediately.
I take Regents review seriously and I expect the same from each class.
The time to relax is AFTER June 21. Until then, you have a lot of knowledge to practice and reinforce. I hope that ALL of you will make the commitment, as I have to you, to achieving a very high score on the Regents and that you will not only NOT settle for a grade below 90, but also that you will strive for the elusive 100 (only 7 students at our school have ever achieved the perfect score on the post-2002 written Chem Regents; not many more in the entirety of the State have achieved a 100 i.e. you will have bragging rights for LIFE if you accomplish this feat).
On June 21, you will be taking your ELEVENTH full Regents exam, at the least!. If you work earnestly and correct any and all errors and uncertainties, I think that you will be well-versed by then.
Stay strong,
Mr.Cicale
p.s.
Those of you who are prepping for the SAT II, here is a nice link for the exam:
http://www.sparknotes.com/testprep/books/sat2/chemistry/
I will try to scan my answer key to the Achievement Test handout that I gave out last week. It's a lot to scan so it may take a while.

Here is a link with some animations regarding our Nuclear Unit:

http://highered.mcgraw-hill.com/sites/0073656011/student_view0/chapter23/elearning_session.html

Make sure that you read and complete Topic 12: Nuclear Chemistry in the orange review book. The file with answers will be posted on the class web page.
The Nuclear/Organic test is scheduled for next week on Wednesday.
Two full Regents exams will be assigned over this extended vacation. These tests will be collected and graded. Since the answer key is readily available, the grade will be based on the accuracy and quantity of work shown for EACH question (i.e. formula, calculations, definitions, principles, explanations). For the free response B-2 and C sections, I expect MUCH MORE EXTENSIVE/ELABORATE honors-level answers than those in the Regents answer key. One word or phrase answers will not receive credit.

The second that the bell rings tomorrow, be ready with questions from the first two practice Regents. We have to get A LOT of questions clearly explained with only ONE day of review this week.

Okay, we're (almost) finished with the course proper; I will ground you in nuclear half-life and nuclear applications tomorrow and during our review classes.
Since we have so few school days for in-class review, we must review thoroughly yet efficiently. I expect any assigned work to be analyzed and done using the test-taking skills that I have been stressing throughout our course. To maximize the benefit of this review for you, circle, highlight, take note of any questions that you are not absolutely sure of. Have those questions ready as soon as the bell rings for class.
Since all of the answers to all of the Regents are available and easily obtainable, I will be checking your test papers for the work shown for EACH question on parts A, B-1, B-2 and C. That work should at least include the formula/equation used, the reason or explanation, or the scientific definition of the term in question.
I will give further instruction on this as we review.
By the time we are done with all of our review sessions (even beyond June 7, schedule pending), you will be finely-tuned Chem Regents test-taking machines who will ace the Regents.

Complete your scantrons using the following information; make sure that you bubble in the information, also.
Test In: Chemistry (print on first line of the form)
SCHOOL BEDS CODE: 580413175554
STUDENT ID NUMBER: (enter your #)
Booklet No. - to be entered tomorrow.
Form No. - to be entered tomorrow.
Thank you.

Poor Barbaro. Not only did he break through the starting gate before the race, but also he broke his leg above and below his ankle just as the race began. These are the unlikely things in horseracing that are hard to foresee. It's even more tragic that this should happen to such a potential super-horse. Even though he was taken to the top veterinary school and clinic in the world (U. Penn), there is little hope that Barbaro will survive.
Sadder.
Every day is a gift.

Lots of good Nuclear Physics tutorials up on the webpage; study them, do the reading and start on those worksheets; you don't have to complete the worksheets yet because we have to do the math part of nuclear,half-life equations, on Monday.

I posted the August 2002 Chemistry Regents which you can take as a little warm-up Regents. The purpose of this test is just to see what information you know by heart and can readily apply and also what you need to ask questions about. Basically, treat this Regents as a diagnostic test. Make lots of notes and mark-ups about anything that is puzzling, confusing, unfamiliar, vexing or troublesome. Then, you will have a set list of questions ready to ask me when we begin Regents review on Tuesday. The exam format has changed a little since then: specifically, parts B-2 and C consist of 35 questions now instead of the "12" questions that are on the 2002 exam. HOWEVER, the 12 questions on the 2002 exam are really broken up into multiple parts so the format hasn't really changed much, the B-2 and C parts of the test are just chopped up into smaller and sometimes unrelated pieces now.

However you do on this first of many practice tests, if you prepare diligently over the next one month: taking exams earnestly (no peaking at the answers) reviewing, analyzing, improving your writing (being specific and on point) and asking me lots of questions, EVERY ONE of you HAS THE POTENTIAL to score a 100 on your 2006 Chemistry Regents! You have been training with heavy weights all year. Now, with proper techniques and practice, you can ace this exam as the vast majority of my past Honors students have done in the past.

Read the test-skills procedure first and then take the exam (make sure that you have the handy-dandy REGENTS Reference Tables, available on the class webpage): do parts A and B-1 multiple choice on Saturday, parts B-2 and C written response on Sunday.


FYI:...Saturday you can watch the second leg of the Triple Crown. Barbaro, one of my top two in the Derby, is ready to take this second jewel. Here is my prediction of the future:
Like Now guns out of the starting gate with Brother Derek giving chase. They set a blazing pace and Barbaro is hanging third or fourth with Sweetnorthernsaint right beside him. As they turn for home, Barbaro opens up the booster engines and blows by the tiring Like Now; Barbaro engages Brother Derek head to head; Sweetnorthernsaint lurks on the outside...they come to the wire with Barbaro pulling away!
ooookay, let's see what kind of soothsayer I am...

Be sure to check out these two good orgo links complete with animations and tutorials:

http://highered.mcgraw-hill.com/sites/0073656011/student_view0/chapter24/essential_study_partner.html

On this page,only the movie links are active:
http://highered.mcgraw-hill.com/sites/0073656011/student_view0/chapter24/elearning_session.html

Friday, May 19, Day 4:
The exam will BEGIN at 7:30 AM so be in your seats ready to write at that time. The test is strictly (and, this time, accurately) timed. There will be no extra time whether or not you are late.
The final exam is a significant part of your fourth quarter grade and, in the past, has almost always matched the AP exam score.
See you tomorrow.
Mr.Cicale

To help those of you who have somehow forgotten how to take a test, here is what you should do:

When you see the common test phrase, "justify your answer", you must seriously and in EXPLICIT DETAIL state your reasons for choosing your answer. That requires you to explain, step by step, WHY AND HOW your answer must be true.
Merely restating the data in the question will NEVER suffice (even on the REGENTS!).

Many questions on the test explicitly stated that you must show the equation and formula used in your calculation. You must write the general formula FIRST and then plug-in the numbers/data correctly.

NOT ONE PERSON correctly explained acidic/basic/neutral salts...the appropriate phrase is (for NaCl), " NaCl is a salt that can be formed from the neutralization of HCl, a strong acid, with NaOH, a strong base thus forming a neutral salt.

Even though some people know what an Arrhenius base is (forms OH- in solution) and a Bronsted base is (H+ acceptor), MOST of you chose a SALT! NaBr which cannot accept H+ (not even the dissociated Br- can because HBr is a STRONG ACID and would IMMEDIATELY release the H+ back to the water). For the record, all NEGATIVELY charged polyatomic ions (except NO3-, ClO4-, and HSO4-) are Bronsted bases because they can easily accept H+. Make sure that you review and CORRECT your test. Do NOT let failure go uncorrected!

...for the hw this weekend, a question from last year follows:
Just want to post a reply to one of the questions about the worksheets (speaking of which, the Table "L" referred to on the worksheets is really Table "N" in our reference Tables):
How do you determine whether or not a reaction will occur in water? I think that the worksheets are using different reference tables because all of my calculations for voltage have been off, but only because they are using different numbers.
Answer:
The reaction in water means the reaction in "aqueous solution". That means that the salt listed is dissolved into its aqueous ions. Then, you just look at which type of single replacement reaction is occurring: metal replaces metal cation or non-metal replaces non-metal anion.
Example:

KI (aq) + Cl2 (g) --> I2 (s) + KCl (aq)
is really
K+ (aq) + I- (aq) + Cl2 (g) --> K+ (aq) + Cl- (aq) + I2 (s)

when you connect the REACTANTS I- and Cl2 on Table N, the line goes downhill which means that the reaction is spontaneous...i.e. chlorine is a more active (attracts electrons better) non-metal than iodine. Note that the K+ (aq) is just a spectator ion because it cannot be oxidized ( K2+ would be waaay less stable than K+).
The worksheet book uses mostly the same electrode potentials (some differ by 0.01 V) so if you are only off by a couple of hundredths, that is fine.

Here is a link to many a fun chem demo that are either too dangerous for class or too long...enjoy!
http://www.klte.hu/~lenteg/animate.html

Check out the "burning gummy bears" demo and the 55-gallon drum demo among others...
Here is a great redox link in which you can manipulate metals and solutions for single replacement redox reactions: (click on the "molecular scale reaction" button to really see what is happening)
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/redox/home.html

...and here's another electrochem animation link:
http://highered.mcgraw-hill.com/sites/0073656011/student_view0/chapter19/elearning_session.html

Honors: Given the pace of our electrochem unit, which is fast but not lightning fast (due to the thorough explanations and multiple examples), I am scheduling the unit test for next Tuesday instead of this Friday (waits for cheers to abate).
That means that you have the whole weekend and Monday to do and review the worksheet problems, the review book reading/questions, the notes with multiple examples, and the text reading. As a result, I expect great results next Tuesday especially from the few who have slacked on the past two exams (about which you have not come to extra help to correct!).
AP: Congratulations on your AP Chem effort. Thanks for making the effort to come in at 6:30 AM for last minute review. I hope that it warmed you up for the exam and that there is a 5 on your score report in July.
Your final will be given on the next day 4 from 7:30AM until 9:45 AM; the exam will have the AP exam format except that it will have a shorter part I section.

Random-er: here is a link to those corny NBC public service announcements, my latest form of entertainment for laughs (check out the Donald Trump and Miguel Ferrer ones):
http://themoreyouknow.com/
...that piano at the end is sooooo "it's all gonna be alllllll right"
:)

Ten short/long months ago, we started our extensive preparation for tomorrow's exam- the culmination of the AP Chemistry course. I thank you all for your dedication throughout the year in this, the fastest paced course in our school (sometimes I had to talk faster than those shady disclaimer guys at the end of car and pharmaceutical commercials).
Tomorrow, it will be time to show off your knowledge. By show off, I mean that you should display your test-taking skills and your relatively vast chemistry knowledge. There will be many questions that need to be read carefully, especially in part I; you should carefully annotate most questions (parts I and II) and underline/CIRCLE any data, units and, of course, what is actually asked for. This will keep you focused on what you need to do.

You don't have to be calm for the exam; calm is overrated and can actually be counterproductive. Put all of your excess energy into the test; go the extra distance by writing things out clearly and in detail. READ WHAT YOU WROTE, if only once after you wrote it.

DRAW, DRAW, DRAW pictures, sketches, graphs , diagrams, orbital diagrams, configurations....you are helping YOURSELF when you keep track of information that you can SEE instead of keeping everything in your mind.

Take a 20 or 30 second break if you need to once in a while...make sure that a window or three are open and do not use shallow breaths (though deep breathing will make you seem psychotic, too- so just breathe normally).

So, put on your game face tomorrow. You are prepared; I have a "decent" record of preparing students for standardized tests. This class is on the verge of breaking the scoring record tomorrow. You only take the AP Chem exam once- make it an exceptional performance after which you have no regrets and a sense of catharsis and great accomplishment.

See you tomorrow for our last second prep, calculator check and timer check!
Good night, sleep as well as you can; I'll have bagels in the AM (carbs = thinking =points on the AP)

That's the mighty and undefeated Barbaro who dominated 19 other Kentucky Derby thoroughbreds yesterday. An awesome performance. Speaking of which, we have our own big test to dominate on Wednesday (it would have been nice to see A.P. Warrior win yesterday but, what's in a name?).
Thanks to Katelyn and Andrew for coming in and sacrificing their Sunday afternoon; they got some valuable instant feedback on their AP exams.
I will give the hard copy of that test to the rest of the class tomorrow. Make sure that you take the test under strict test conditions, then score the test and see me about ANY question that caused uncertainty or took you too long to answer.

Our tenth practice AP exam is posted for Monday. Including the spring break assignment and the practice exam last week, by Tuesday, we will have completed 12 AP Part II exams and 5 AP Part I exams !!! (not including the part II questions that we started in February!). You have a lot of experience with this test; you will be very familiar with the question types and the exam format. Of course there can always be a few minor surprises but they won't significantly affect the test or your score as long as you deal with those questions methodically (or skip/guess on them if they are troubling you) - stay cool and confident- there are always a few weed out/ psyche out questions purposefully and strategically placed on the exam to destroy those who have poor test-taking skills (i.e. can't move past a question and get upset during the test).
Anticipate that; you've already dealt with those situations during the practice tests! Just go into your AP Chem exam and take control over the test. At this point, that will be a formality.
Good times.

1. I still can't get two people in a row to simply plug the numbers into a Hess Law equation; will you please write out the equation and then explicitly substitute the numbers and then PROPERLY follow PEMDAS (when you remove the parentheses from something that is being subtracted, you MUST change the sign of EACH term that was in the parentheses).

2. This isn't a correction, just an important note:
the % ionization of a weak acid is usually pretty small: about 5 to 10 percent in most common solutions. However, you can SUPPRESS ionization of the WEAK acid EVEN FURTHER by adding a STRONG ACID to the weak acid solution. You can see this effect via Le Chatelier:
HA --> H+ + A -
by adding a strong acid, the concentration of H+ in solution increases which causes a stress on the PRODUCT side of the weak acid ionization equilibrium; the system relieves that stress by shifting towards the reactants. Kinetically, the reverse rate has to increase due to the increased collision frequency between the H+ and the A- due to the increased concentration of H+.

3. You CANNOT claim that a molecule is polar simply because it has very polar BONDS within the molecule. If you think that you can, just think of CO2 to see that YOU can have very polar bonds WITHIN a molecule yet, the dipoles cancel due to the CO2 linear molecular geometry that causes the equal C-O dipoles to be oppositely oriented; thus, the dipoles cancel causing CO2 to be a non-polar molecule.
Any molecule that has polar bonds will be polar ONLY IF the dipoles formed by the polar bonds DO NOT CANCEL i.e. ONLY IF the DIPOLES ARE NOT be symmetrically distributed.
Therefore, you MUST MUST MUST draw the molecule AND EXPLCITLY refer to its MOLECULAR GEOMETRY/SHAPE in your answer....i.e. CH2F2 is polar BECAUSE the H and F atoms are TETRAHEDRALLY ORIENTED about the carbon; if the H and F atoms were in a SQUARE PLANE (with the F's at opposite corners) then that molecule would actually be nonpolar because the two C-F dipoles would cancel because they would be equal and oppositely oriented.

4. I just graded THREE TESTS IN A ROW in which the Lewis structure of NO3 - had SIX VALENCE ELECTRONS AROUND THE CENTRAL ATOM!!!
If you have used up all of the valence electrons on the TERMINAL atoms, you must then use lone pairs from the terminal atoms to form DOUBLE OR TRIPLE BONDS UNTIL THE CENTRAL ATOM HAS AN OCTET!!! (except for B and Be and odd-electron moecules/ions!)

Honors: Test covers all unit notes/worksheets/practice tests/review book work. If you've done all of those problems and taken good notes, get ready for a 100.

Here is the link from class today:
Remember, the reaction is
2H+ + 2 CrO4 2- (yellow) --> Cr2O7 2- (orange) + H2O

http://www.chem.uiuc.edu/webFunChem/chromate/ChromateIndex.htm>

and, for another color equilibrium, recall our redox titration:

MnO4 - (purple) + H2O2 --> Mn 2+ (colorless) + O2 + H2O

so the endpoint occurs when the solution in the flask stays pinkish (between colorless and purple)...permanganate acts as its OWN indicator because it is a colored ion.