<p>@Hawkace The curve for AP Bio was dropped from 20% to 5% when they released the new exam. If they do similar things to this one, it will mean that you need 60+/75 to get a 5. It’ll be ridiculous. I could do those on the older formats because I’m a math kind of guy, but with the revisions they’re making it’s gonna be hell.</p>
<p>@HollowSunsets Y is correct because of electron affinity related things
z is also correct because, well, gas to solid.
x is opposite (breaking bonds)
w is opposite of correct
v is obviously wrong</p>
<p>35 is simple stoichiometry and limiting reactants. Pretty sure that’s all you need to know to figure that out.</p>
<p>Does writing a charge as - 1 instead of 1- mean you will lose a point?
Do you always have to include proper sig figs? </p>
<p>Can someone PM me the official practice test? I just really want to get familiar with the problems cause I have Princeton Review</p>
<p>@pixelations If you want to get familiar with the problems learnerator.com has some very good sample questions (full package with all the questions isn’t free though)</p>
<p>@superscientist alright thanks bud.</p>
<p>And I’d say yes on the sig figs, but I don’t know much about the test. Our teacher strongly emphasized that we use correct figures</p>
<p>@jamesjunkers for the charge I’d say it wouldn’t hurt to memorize them. And for sig figs if you’re off by more than 1 you lose points.</p>
<p>what does it mean for something to be polarizable? What is polarizability?</p>
<p>@MasterMaestro Think of polarizability as how easily a molecule can become polar (like a dipole). This means that the molecule may be partially positive on some sides and partially negative on other sides. Polarizability increases with the number of electrons you have. The more electrons you have, the more easily the electrons can be attracted to another partially positive portion of another molecule. This would lead the electrons to cluster closer to that side near the partially positive portion of the OTHER molecule, and the molecule itself would now be polarized. Polarizability thus increases with atomic size as well (since atomic radius increases with number of electrons and sublevels).</p>
<p>Will we be tested on the Arrhenius equation, as it was taken off the reference table? </p>
<p>@jamesjunkers No, it was taken off of the curriculum because it doesn’t help with understanding the big ideas. :)</p>
<p>@jamesjunkers i do not think so because that is a bit obscure topic. plus, in my class we never went over that</p>
<p>@jamesjunkers if you look at the syllabus it does say that you need to understand it, but not perform calculations with it</p>
<p>Thanks all 
I really hate that all the math was taken off… The math is what’s been giving me a high 90 in AP Chem all year :(</p>
<p>A 100.0 mL solution of KOH was titrated to an endpoint with 50.0 mL of a 2.00 M H2SO4 solution. What is the molarity of the KOH solution?</p>
<p>can someone explain this problem from the Barron’s test? The explanation is a bit confusing</p>
<p>Also, if someone wants to make a Google doc, that’d be nice… If not I’ll make it later</p>
<p>@besthbk I’m not 100% sure if this is correct because I haven’t reviewed Acid/Base reactions yet, so I don’t know if H2SO4 being polyprotic would affect the answer. I would just multiple the molarity of H2SO4 by its volume to find the moles of [H+] and divide by 100 mL or .100 L. </p>
<p>@besthbk at the endpoint of a titration, the number of moles of H+ and OH- are equal so you should start by calculating the numbers of moles of H+ by multiplying 2(2)(0.05) since each H2SO4 molecule has two H+'s. then set that equal to the number of moles of OH-. (0.1)(X Molar)=2(2)(0.05). just solve for molarity</p>
<p>hope that helped</p>
<p>@besthbk Well you have to think about the significance of the endpoint. The endpoint is more than often also your equivalence point, or the point in which the moles of the titrant is EQUAL to the moles of the solution being titrated. So they’re telling you here that at the endpoint the measured volume of the 2.00 M solution of H2SO4 was 50.0 mL- from this you can easily calculate the # of moles and use that same value in order to calculate the molarity of KOH (molarity is mol/L as you probably already know)</p>
<p>@SmartAlec I know how to do the problem but I am confused as to why we have to multiply the H+ ions by two.
if possible, could you make that a little more clear</p>
<p>Can anyone explain number 60 on the practice multiple choice test?</p>