<p>I still don’t get a few things for tomorrow…</p>
<p>Hybridization and sigma/pi bonding</p>
<p>Paramagnetism/Diamagnetism</p>
<p>Buffered Solution ph/ Henderson equation…</p>
<p>Are these important for tomorrow? This is my first (and hopefully only time) taking it and I’ve only done regular chem (since AP needs regular first and no honors courses offered). I’m aiming for an 800.</p>
<p>1 mole of atoms = 6.022 *10^23 right?
well say u have a diatomic thing. would u double up the number? or would u keep it the same? mad confused on this. got 3 questions wrong cause of this…</p>
<p>@Knight - </p>
<p>Hybridization is really simple. Take NH3. The structure would have an N bonded with 3 H’s and have a lone pair on top. Since there are 4 regions of electron density (3 bonds and 1 electron pair left over), the hybridization would be sp3. 1 from the s, and 3 from the p = 4.</p>
<p>sigma/pi bonding is similar. if you have a single bond, you only have a sigma bond; but if you have a double bond, you have BOTH a sigma bond AND pi bond. in a triple bond, you have a sigma bond and 2 pi bonds. </p>
<p>I’m not too sure about paramagnetism/diamagnetism though… and on the kaplan sat review book, buffered solutions don’t take up a lot, but they do ask a few quesetions.</p>
<p>Anyone have a good website for Atom/Ion COLORS?</p>
<p>Hey Chicken on Rice I’ve seen you around in the AP Chem threads :)</p>
<p>I would say double it because eg. H2 there are 2 Hydrogen atoms in hydrogen gas.</p>
<p>bandgeek I have a word doc with loads of ion colors. PM me your email if you want. </p>
<p>Also does anyone know if there are released sat chem past papers on the net?</p>
<p>@bandgeek
I found this [chem</a> ap flame test colors flashcards | Quizlet](<a href=“http://quizlet.com/2711155/chem-ap-flame-test-colors-flash-cards/]chem”>http://quizlet.com/2711155/chem-ap-flame-test-colors-flash-cards/)
[Ion</a> Colors flashcards | Quizlet](<a href=“http://quizlet.com/3075606/ion-colors-flash-cards/]Ion”>http://quizlet.com/3075606/ion-colors-flash-cards/)
hopefully it will help :D</p>
<p>@orangefroot - <a href="mailto:bandgeek156@gmail.com">bandgeek156@gmail.com</a></p>
<p>lolol</p>
<p>@omchi23 - thanks so much :D!</p>
<p>an element is paramagnetic if it’s outer shell isn’t completely filled, i believe.</p>
<p>if anyone took the 2005 real sat practice test, its a lot harder than sparknotes, which scares me. what did people get on the barrons tests?</p>
<p>Ah ok, thanks</p>
<p>Hybridization is still really confusing for me though</p>
<p>In a molecule like XeF2 and OF2, how do you get the hybrid orbitals?</p>
<p>Im so screwed if there are hybrid orbitals tomorrow. It would SUCK if a whole classification set was hybrid orbitals and you had to match the molecule to the hybrid orbitals…</p>
<p>Other than that, I think I’m ready. Just hoping its like the Official BB test where I got a 770 (mainly b/c of some stupid mistakes).</p>
<p>All I remember (from studying for AP Chem) about paramagnetism is that it’s when there’s an unpaired electron in the outer shell and, because of that, it has greater attraction to magnetic fields - but I’m not 100% sure. The only reason I remember anything is because I think “di” as in two electron/a pair and “para” as in paralysis, which kind of relates to being more susceptible to magnetic forces… kind of.</p>
<p>I’ve just started studying my Barron’s book and am about halfway through my first practice test, so I don’t have a score yet. I’m half-scared, half-resigned and just trying to trudge through Barron’s math…</p>
<p>edit// Just wanted to add a mnemonic that my friend and I used for flame colors on the AP: Sr. CaLi. It’s like California, which is hot, so all those three elements burn red. I’m not sure if that helps, but it’s there. xD</p>
<p>For hybridization, I’ve never completely understood it. I just think that if there are two bonds, it’s sp; three bonds, sp2; etc. Then each lone pair is like another bond, so two bonds and a lone pair would be sp2. So for molecules like XeF2 and OF2, I would draw them out and count the bonds and any lone pairs. Again, I’m iffy on the subject, but it seems to work most of the time.</p>
<p>for OF2, it would be sp3 IN RESPECT OF oxygen.</p>
<p>if you draw the lewis structure for OF2, you’d have 2 single bonds and 2 lone pairs for Oxygen, right? That would mean FOUR locations of electron density for Oxygen. Therefore, you’d have s1 and p3 so that the 1 + 3 = 4. make the connection. Therefore, the hybridization of O for OF2 is sp3 (omitting the 1 next to the “s”).</p>
<p>for XeF4, remind yourself again, that Xe can disobey the octet rule and have an expanded octet since it’s after period 3. draw the lewis structure and you’ll notice that Xe has 4 single bonds and 2 lone pairs of electrons. 4 + 2 = 6 locations of electron density. therefore… it would be sp3d2. recall that it’s s1 + p3 + d2 = 1 + 3 + 2 = 6.</p>
<p>I don’t really know why s only goes to 2, and p goes to 3, but just keep that in mind.</p>
<p>Ohhh I get it now. Thank You! Explains it a lot better than the Zumdahl textbook I bought…</p>
<p>can someone please explain buffer solutions/Henderson stuff?</p>
<p>You don’t need to know the Henderson-Hasselbach equation for the test. It is highly unlikely that CB will get you to do logarithms without a calculator. </p>
<p>Buffer solutions resist the change in pH and they are generally formed with a weak acid/weak base and its conjugate base/acid (respectively).</p>
<p>i’m gonna screw up on the descriptive chem/basic knowledge stuff that appears usually appears in the beginning of the test.</p>
<p>I’m going to take the blue book as practice and then go to sleep. Next up, the SAT Chemistry test…</p>
<p>Guys, what’s the curve like on this test? I believe something like -5 is the average 800 curve…but sparknotes says that -2 is 800…which makes absolutely no sense because i got like 75/80 on their 3rd practice test and got an 800.</p>
<p>Oh yea the descriptive chem section…</p>
<p>What is some chem ‘trivia’ we have to know? Besides the ion colors, flame tests, earth atmosphere…?</p>
<p>The BB curve is like -3=800…</p>
<p>my policy for tomorrow is…when in doubt, omit. according to my mcgraw hill book, even if i omit up to 10, i still have a change of getting at least a 780.</p>