<p>^ nice i specifically wrote the Q > ksp thing or whatever it was</p>
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<p>Well the question told that bromothymol blue was added. the indicator turns yellow in the presence of an acid, and the solution was acidic.</p>
<p>Wow! Has anyone looked at the Form B Free-Response? It actually looks pretty awful! Like, it’s all pretty doable, but there’s organic, titrations, weird reactions, and NO atomic structure question. </p>
<p><a href=“Supporting Students from Day One to Exam Day – AP Central | College Board”>Supporting Students from Day One to Exam Day – AP Central | College Board;
<p>Sucks to be international…lol</p>
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<p>I think the important thing to note is that you are carrying out the titration “well past the equivalence point” … if you look at a titration curve of a strong base with strong acid, you’ll see that adding even a tiny amount of acid past the equivalence point results in a significant drop in pH.</p>
<p>As this was maybe the only thing I retained about acids and bases this year about titrations (thank goodness we didn’t have an actual FRQ about them; I would’ve died), I thought the question was way too easy and so I actually put down:</p>
<p>“It would be unequivocally yellow.” I giggled to myself afterwards. :P</p>
<p>I liked acids & bases… Wish we had it on this test.</p>
<p>so if my MC was ~60/75 and I get about (3/5)ths of the FRQ right… can that still be a 5???</p>
<p>Someone come to my aid PLEASE…</p>
<p>yes you can get a 5 with that depending on the curve</p>
<p>I got all of 4, 5, and 2. (missed a few points here and there though) Got about 1/2 on 6 most likely, on 1 I hardly answered anything and on 3 I did about 1/2. If I got a 35 or so on the MC would that be a 3?</p>
<p>And for the endo/exo problem on 2? I explained it right but put exothermic? Would I receive partial credit?</p>
<p>Hmm… How many points would they mark me down if I put Q > Ksp without any mathematical calculations? (I knew what to do after the calculators were taken away, and I took a wild shot at the dark.) And also, how many points would it be if I put the entire equation (KOH + HN03 -> H20 + KN03) (I completely forgot about the “no putting unchanged ions” rule).</p>
<p>About halfish on 1-3
10/15 pts on 4
5-6 perfect except for Zn config on 6</p>
<p>how many points can you get in the frq?</p>
<p>anyone know the curve?</p>
<p>Really? I thought nitric acid was a weak acid compared to potassium hydroxide and I thoughti t was going to turn blue lol</p>
<p>not trying to sound like that pretentious guy that knows it all</p>
<p>but i was going through some of these answers and saw some major flaws
most noticeably in NewAccount’s initial answers
so instead of drudging through the twelve pages of answers and arguments i thought i would just put down the answers</p>
<p>if you would like to dispute my answers then go for it. but i guarantee that there is evidence for each of my answers.</p>
<p>here are the answers to the conceptual / essay questions.</p>
<p>4)
a) 2 hydrogen ions + hydroxide ion –> 2water molecules
the solution would turn yellow because of the excess hydrogen ions that would make the pH less than 7, or acidic, and therefore turn yellow in bromthymol blue.</p>
<p>b) Propane (CH3CH2CH3) + 5 diatomic oxygen molecules –> 3 carbon dioxide molecules + 4 water molecules
the resulting solution will be acidic because carbon dioxide and water will react to form carbonic acid which will release hydrogen ions into solution, making it acidic.</p>
<p>c) 2 hydrogen peroxide molecules –> 2 water molecules + diatomic oxygen molecule
-1 is the oxidation state of the oxygen in hydrogen peroxide</p>
<p>5)
a) well since i cant visually show it to you guys its just H C C H with two electrons between the hydrogens and carbons and six electrons between the carbons</p>
<p>b) ethyne, because the stronger the bond (i.e. the more bonds there are) the harder two atoms pull on each other, thereby decreasing the distance between them, or the bond length.</p>
<p>c)
i) trigonal planar
ii) tetrahedral</p>
<p>d) This statement is false. The heat goes into breaking intermolecular bonds, which consist of hydrogen bonds, dipole-dipole bonds, and dispersion force for ethanol. The bonds mentioned in the formula are intramolecular bonds and require much more energy to break than the intermolecular bonds that are broken during the boiling process.</p>
<p>e) Both ethane and ethyne are non polar because both sides of the carbon atoms are equal and pull on each other with equal force, resulting in net non-polar atoms.</p>
<p>f) Basically, one contains hydrogen bonds and the other doesn’t, so while they are both soluble due to their polarity, ethanol is moreso due to it’s O-H bond, as opposed to ethanethiol’s S-H bond.</p>
<p>6)
a) 1s2 2s2 2p6 3s2 3p6 3d10</p>
<p>b)Zn+2. although i had a long explanation on my actual test, the shortened explanation is that positively charged ions always have a stronger force than they’re ground state form. for that reason, it takes much more energy, ionization energy, to pull of the ion’s valence electrons.</p>
<p>c) Al</p>
<p>d) The salt bridge releases K+ ions into the negatively charged cell to neutralize the net negative charge that builds up as a result of the aforementioned reaction, while NO3- ions are released into the positively charged cell to neutralize the net positive that also builds up as a result of the aforementioned reaction. (aforementioned reaction is referring to the reaction given on the top of the question)</p>
<p>e) Turned out to be about 0.9 volts or something like that</p>
<p>f) Delta G turned out to be negative for this one. You can use the equation that relates delta G to the cell potential or just realize that galvanic cells do not require electrolysis to initiate the reaction and therefore contain spontaneous reactions, which makes delta G negative by definition.</p>
<p>g) Cell voltage will increased, as shown in the Nernst equation. if the numerator is decreased by a power of ten, then log of the reduced ion over the oxidized ion will become negative, making the correctional factor -(0.0592/n)(log Q) positive, thereby increasing the cell potential.</p>
<p>if you guys have any questions feel free to ask
but i am really confident in my answers and will be more than willing to discuss these problems</p>
<p>Lol 2 hydrogen ions and hydroxide ion makes a hydronium ion, not 2 water molecules…
it was just
H+ + OH- > H2O</p>
<p>@ omgpie911. Did we have to write a NET IOnic equation? I just wrote the chemical reaction, like it asked for.</p>
<p>Also, does getting about 67% of the points constitute a 5? If so, I think I got a 5.</p>
<p>I meant for the AgBr + NaI one, obviously not the section 4 ?'s.</p>
<p>@ sheezy, here are how the prediction products are graded:</p>
<p>1point: reactants (with correct charges)
2 points: products (with correct charges)
1 point: balancing
1 point: bottom question</p>
<p>SO, according to what you put, you only got one point for putting H2O. If you got the bottom question correct you got 2/5, but if not, you got 1/5 for that question.</p>
<p>Here is another example of predicting products grading. For #3, I put H2O2 –> H2 +O2</p>
<p>Accordingly, I would get one point for reactant, one point for product (O2), and since I put (-1) for oxidation state, a point for the question. Therefore, I obtained 3 out of the 5 points.</p>
<p>I scored a total of 12/15 (4/5, 5/5, 3/5)</p>
<p>^ samesies!! 12/15</p>
<p>Isn’t it Zn+2 we have the same number of protons, but more electrons in the Zn atom</p>
<p>More electrons means more electron-electron repulsion. Means lesser IE</p>