AP Chemistry 2010 Study thread! Come on people!

Test Preparation AP Test Preparation
201

<ol>
<li><p>which of the following pieces of lab glassware whould be used to most accurately measure out a 25.00 mL sample of a solution?
a) 5 mL pipet
b) 25 mL pipet
c) 25 mL beaker
d) 25 mL Erlenmeyer flask
e) 50 mL graduated cylinder</p></li>
<li><p>Which of the following solutions has a pH greater than 7.0?
a) 0.10 M KBr
b) 0.10 M NH4Cl
c) 0.10 M HC2H3O2
d) 0.20 M NaF
e) 0.10 M HI</p></li>
</ol>

<p>After these questions, I’m going to go for now and come back tonight.</p>

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<ol>
<li>
B - pipet is far more accurate than the rest.</li>
</ol>

<p>64.
D - cation of a strong base and anion of a weak acid - forms basic salt</p>

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<p>Yep! 10char</p>

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<p>Any more? :p</p>

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<p>62) e?</p>

<p>64) I eliminated c but I have no clue :(</p>

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<p>could you explain why 75 is b?</p>

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<p>Ooooooh I see it now. Very helpful thanks!!</p>

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<p>I will use a picture to demonstrate why 75 is B. Click: <a href=“http://www.mikeblaber.org/oldwine/chm1045/notes/Bonding/Resonan/IMG00007.GIF[/url]”>http://www.mikeblaber.org/oldwine/chm1045/notes/Bonding/Resonan/IMG00007.GIF&lt;/a&gt;&lt;/p&gt;

<p>As you can see, O3 has a bent molecular geometry (2 bonding areas, 1 non-bonding), and it is a resonance hybrid of two lewis-dot structures. O3 is the only molecules that fits the criteria of the question.</p>

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<p>Thanks!</p>

<p>On the exam though, how should I approach this sort of problem? To me it seems like a waste of time to draw out the structures for each of the 5, but maybe thats the only way?</p>

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<p>I had previous knowledge of O3 having a bent shape and two resonance structures from discussions I’ve had in class. I immediately recognized it as the right answer.</p>

<p>If you didn’t know that, then yes, the only way is to draw them all out.</p>

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<p>Can anyone explain #59 on the 2008 multiple choice?</p>

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<p>

</p>

<p>Look at the equilibrium reaction, count the reactant molecules and product molecules, there are more reactant molecules, so the equlibirium favors the reactant, therefore it must be 0 < K < 1.</p>

<p>K can’t be 0, because that means there is no reaction
K can’t be 1, because that means reactant and product concentration is the same
K can’t be over 1 because that means it favors product.</p>

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<p>Thanks, Lemone! At first I didn’t take into account that there are more reactant molecules than product molecules.</p>

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<p>Currently doing 2002 MC as practice. Let’s see how this goes.</p>

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<p>I thought 2002 was REALLY easy. Like unrealistically easy. I got like 63 right, 8 wrong. I haven’t taken the 2008, but I think that should be a better gauge than 2002. I’m not sure what was up with 2002, though…</p>

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<p>Anyone have like a list of all lab stuff we need to know?</p>

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<p>Just finished the 2002.</p>

<p>65 right, 7 wrong.</p>

<p>I’ll probably do the 1999 tomorrow.</p>

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<p>I did the 2002 and got 63/75 and then the 2008 and got 65/75 with a couple days of studying. I feel they are both accurate measures of what the MC portion should be like. If you look at the questions closely, it is obvious that they are asking very similar questions just different wording.</p>

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<p>do we have to know experiments?</p>

<p>IE. memorize that millikan’s experiment found the charge of an electron, or dalton proposed the ratio of elements etc</p>

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<p>No we don’t.</p>