SciHawks

Here is a link to that sulfur hexafluoride video from today:
http://www.youtube.com/watch?v=GutiNPwzUA8

AP Chem - discussed the New Year's assignment; this assignment will be posted on Edline this weekend. I will send you an email as soon as I upload the assignment.

Bio - finished the last two lab write-ups; we begin the digestive system (nutrition) and endocrine system (regulation) in 2012.

AP Chem - took the unit exam on Bonding/Molecular Geometry/IMFA's
We will do some of the winter break assignment questions tomorrow while relaxing with our well-earned bagel party (the one that was stolen by the class of inchoate, rabid freshmen who obviously own a supermarket).

Bio - 10/11 reviewed proper test-taking skills that maximize accuracy and confidence while minimizing careless and other types of errors.
We took the unit exam on Locomotion.

AP Chem - we further discussed and contrasted delocalized pi bonding and local/regular pi bonding, emphasizing the greater stabilization when 2 electrons are shared among more than two nuclei.
We looked at a complex molecule that contained multiple pi bonds, and showed that pi bonds prevent rotational freedom about the atoms involved in the pi bond. Thus, pi bonds must be broken for a cis isomer to rotate to a trans isomer, and vice versa.
We also further discussed "dative" or "coordinate covalent" bonds, which were named merely to show that one of the two atoms that bond is contributing both electrons in the bond.
Study for tomorrow's bonding/molecular geometry/IMFA exam.

There are more practice files, and a review of proper scientific investigation, posted on Edline.

AP Chem - we finished the remaining molecule ion types for five and six electron domains.
We then focused on the details of delocalized pi bonding, and why it is stabilizing by creating more net attraction among the nuclei and mutually shared electrons.
We also looked at covalent bonds formed when one of the two atoms/ions involved in forming the bond contributes both of the electrons in the orbital overlap region.

Bio - we discussed the structure and features of the various layers that comprise the skin.
We explained how the skin/integumentary system works in conjunction with the circulatory and nervous systems to maintain internal body temperature homeostasis when environmental conditions (internal and/or external) are changing.

AP Chem - we finished the remaining 5 and 6 electron domain molecule and ion types complete with orbital hybridizations, electronic and molecular geometries, as well as molecular polarities (ions CANNOT be polar, they are just a single "ball" of charge).
We will finish up some loose ends, and some common AP applications for this unit.
Then, we will focus on topics to be covered over the break.

Bio - hw is due tomorrow BUT of course we have not yet covered the entire unit.
Thus, omit the following hw questions: 2,3,7,8, and 12. We will, of course, cover those questions, along with review over the next two days.
Today, we discussed cartilage and its functions; we then looked at the three different types of muscle tissue, its appearance (striated/striped vs. smooth), and its cause of action (voluntary vs. involuntary).

AX3 - TRIGONAL PLANAR

AX4 - TETRAHEDRAL

AX4E - SEE SAW/SAW HORSE

AX3E - TRIGONAL PYRAMIDAL

AX2E2 - BENT/V-SHAPED

AX2E - BENT/V-SHAPED

AX5 - TRIGONAL BIPYRAMIDAL

AX3E2 - T-SHAPED

AX4E2 - SQUARE PLANAR

AX2E3 - LINEAR

AX6 - OCTAHEDRAL

AX5E - SQUARE PYRAMIDAL

AP Chem - thank you class for your great generosity and fidelity in putting the "drive" into this food drive.
It was so nice of you to haul in the goods to benefit those in need, whether or not we got a shout out (though that was pretty fun too). I will spend this weekend buying out another aisle in Waldbaum's. :)


Today, we navigated through AX3, AX2E (with delocalized pi bonding shown, though not completely explained, yet), AX4, AX3E, AX2E2, AX5, and AX4E molecule types, along with their requisite orbital hybridizations, electronic and molecular polarities, and finally intermolecular attraction types.
We'll finish up on Monday but I will post the remaining notes on Edline (for AX3E2, AX2E3, AX6, etc)
so that, for these remaining types, you can go through what we did today.

Bio - we discussed the 6 purposes/functions of endoskeletons (functions related to locomotion as well as to other functions i.e. forming blood cells).
We learned the major commonly cited bones of the human body.
We discussed and gave examples of various types of joints, and saw their respective motion ranges.
We defined and discussed tendons and ligaments, and came up with foolproof mnemonics for both.
We saw that muscles work in antagonistic pairs i.e. biceps are flexors and triceps are extensors.

AP Chem - we learned the procedure for drawing the Lewis structure of an odd-electron (valence) molecule i.e. a "free-radical" and we saw that these molecules are relatively highly reactive due to the attraction of the lone/unpaired electron to the nuclei of other free radical molecules without the impossibility of having three or more electrons in a single orbital overlap / bonding region.
Free radicals are very reactive; thus, they can react with and mutate DNA leading to non-functional-protein synthesis and cell death.

Bio - took our unit exam on photosynthesis and cellular respiration.

AP Chem - we played the "formal charge"/fake charge game that sometimes works in determining the more/most significant resonance structure that contributes to the true structure of a molecule.
We then showed the three exceptions to the octet rule in which stable molecules are formed with less than an octet on the central atom (or on H): H, Be, and B molecular compounds.

Bio - tomorrow (Wednesday) is our unit exam on Photosynthesis and Cellular Respiration.
See Edline for additional practice files.
Today we looked at the results of our Elodea photosynthesis experiment in which we used BTB acid-base indicator to detect the consumption or lack of consumption of the acid-forming molecule, carbon dioxide. Consumption of that molecule is evidence that photosynthesis occurred because CO2 is consumed in the synthesis of glucose.
We also went over some of the common hw errors.

AP Chem - we did additional examples of Lewis structures for atoms and ions; we are simultaneously emphasizing Coulombic repulsion of domains (bonding or non-bonding) of electrons around the CENTRAL atom in determining the electronic geometry; ultimately, electronic geometry determines the molecular geometry, both of which determine the molecular polarity, types of intermolecular attraction(s), and thus the physical and chemical properties of the molecules.

Check Edline (starting Friday afternoon) for a brief assignment on Lewis structures and predicting chemical reactions, to be handed in on Monday.

AP Chem - we focused on the causes of extreme dipole to extreme dipole attractions between molecules that have HIGHLY PARTIALLY charged regions. These high partial charge regions are caused by the highly unequal sharing of bonded electrons between H and F,O, or N within a molecule.
The second requirement for these attractions has to do with the distance factor of Coulomb's Law; F, O, and N are the only sufficiently small highly electronegative elements to be able to cause "close proximity" of adjacent highly charged regions of adjacent molecules.

We then began the all-important skill of drawing accurate Lewis dot structures of molecules.
There is ONLY ONE way to draw these correctly.
That is the way we will learn to do so, and then we will be able to predict the molecule's geometry, polarity, and physical properties!

Bio - we compared and contrasted cellular respiration in animals under conditions of sufficient and insufficient oxygen.
We then took practice tests on photosynthesis and respiration, practicing multiple choice test-taking skills.
We also observed the results of the yeast alcoholic fermentation controlled demonstration.

AP Chem - described and explained induced dipole attractions among non-polar molecules, which causes, for example, iodine's solid state even at room temperature, or the condensation of non-polar gases at low temperatures.

Bio - we looked at the formation of ATP molecules from ADP and P and the energy extracted from glucose from respiration. In cells, in order to not waste all of the extracted energy as just heat, the ADP + P reaction occurs by absorbing and storing much of the energy that is released during respiration.


We then took and discussed a quiz on aerobic respiration.

AP Chem - took the unit exam on Periodicity

Bio - we reviewed the two types of anaerobic respiration: alcoholic and lactic acid fermentation.
We then looked at the type of respiration that uses oxygen to extract a lot more energy from the glucose molecule: aerobic respiration.
There are three parts to this process: glycolysis (same as in anaerobic) in the cytoplasm, then , in the mitochondria, the Krebs Cycle reactions which produce carbon dioxide, and then the electron transport chain, which uses oxygen which ultimately reacts with hydrogen, releasing a maximum amount of energy to form a net of 36 ATP.

AP Chem - please thoroughly review your last test; only two students came to extra help to review their tests. Those who did poorly must compensate by studying more effectively, which entails finding out how to do so. I can show you how to study more efficiently and effectively at extra help.
Daily review and copying of notes is a starting point; doing the problems on the practice tests and worksheets, and submitting your answers BEFORE a test for constructive criticism or assessment, will prevent you from making many mistakes on the actual exams.

On this past exam, the following types of errors will not be repeated:
Treating an AP Chemistry exam as if it is a text chatroom; do NOT abbreviate any words or terms; for particularly long and highly repeated words or phrases, you may designate an acronym or abbreviation along with a KEY, after which you may use the acronym/abbreviation throughout that given question.

You absolutely MUST use the key terms/words DIRECTLY from the question within, and possibly throughout, your answer.

Write the general formula that you are using in solving an equation, with each variable labeled in DETAIL (e.g. energy PER PHOTON); of course you should either start with the variable that is being solved for ISOLATED on one side of the equation, so that your calculation and units cancel in ONE step.
If that is not possible, show the derivation of the formula that isolates the unknown variable, and then solve in one step showing all proper unit cancellation.

On multiple choice questions, SHOW YOUR WORK explicitly; NOT FOR ME, but for you. Have it register that many of the questions that you missed were due to your trying to juggle to much information in your head, when you could have instead written things out clearly so that you could SEE how to get the right answer.

Read what you wrote with any explanation and make sure that your answer is LOGICAL (in cause and effect order!), coherent, and that each line relates to the question asked.

The explanation/qualitative part of this course never ends; you must learn to understand and write proper explanations otherwise you will do very poorly for the rest of this course. This often requires much written practice and correction (from me, BEFORE a test).

Our exam on the Periodicity unit on Monday will cover, as usual, all notes from this unit; I will later post a list of possible question types:

Update: On this largely qualitative test, which gauges your understanding in logical order of CAUSE and EFFECT, you will be asked about the trends in the periodic table, as well as selected anomalies.

Here's a tip to help increase the quality and logic of your explanations:
as you write EACH LINE of an explanation, picture the test grader writing/saying, "YOU ARE WRONG; YOU ARE LYING, THE OPPOSITE IS TRUE", and THEN prove the grader/AP reader wrong by stating how and why that person is wrong by stating your evidence/ drawing/ showing your mechanism! This way, you are proving your case, making a thorough, sufficient argument for your explanation.
Also, you should BEGIN YOUR EXPLANATION with a COMPLETE DRAWING AND/OR DIAGRAM that is LABELED and REFERENCED (simply by drawing ARROWS TO THE DRAWINGS OR DIAGRAMS) throughout the explanation.

On tomorrow's exam, expect questions on:
- explanation of periodic trends down groups or (from left to right) across periods in order of increasing atomic number in terms of
1.Zeff on valence electrons,
2.# of OPEL's, and
3.degree of e- - e- repulsion among electrons in the valence or outermost shell.
- explanation of any given periodic anomaly (e.g. ionization energy, electron affinity); the anomaly will be GIVEN. Remember, you cannot predict anomalies, but they can be explained.
- explanation of successive ionization energies, and their relation to determining the number of valence electrons of an element
- explanation of relative sizes of a series of atoms and/or ions
- explanation of the increasingly endothermic successive electron affinity
- general differences between metals and non-metals
- knowledge of the approximate/exact electronegativity values of the 11 non-metals
- predict the products of our known chemical reaction types (anionic/cationic single replacement, double replacement with precipitation, etc.); for anionic and cationic single replacements, that means knowing the relative reactivities of the metals (any metal is more reactive than the four "noble metals", Cu, Ag, Au, and Pt), and of the nonmetals (fluorine is the most reactive, etc.).

Bio - we discussed the two types of anaerobic cellular respiration, each of which extracts merely enough energy from glucose to form 2 ATP molecules. Organisms that can perform only anaerobic respiration are necessarily limited in their energy extraction/production so they are also limited in growth/size (this is why there are no anaerobic organimsms larger than a bacterium).

We showed the two possible anaerobic pathways: alcoholic fermentation in which ethanol alcohol and carbon dioxide are produced from glucose, and lactic acid fermentation, which produces lactic acid from glucose.

AP Chem - we used our knowledge of the properties of metals and non-metals to predict the products of single replacement redox reactions. We reviewed other reactions learned throughout the course.
We discussed the relationship of the periodic trends of the table of elements to the characteristics of what we call "metals" and "non-metals". Elements that have low Zeff on valence electrons and many shells of electrons exhibit the most metallic character (e.g. cesium) . Elements that have high Zeff on valence electrons and few shells of electrons exhibit the most non-metallic character ( e.g. fluorine).

We then gave a detailed explanation of water homeostasis/regulation in a plant via the guard cells that form stomates/pores on the underside of a leaf.