AP Chemistry 2010 Study thread! Come on people!

<p>Oh no I mean high 90s/150 for a 5…that would equate to the mid-60s percentile range</p>

<p>I heard about mid 60% as well. Thanks for the help.</p>

<p>Yes, you disregard the iron’s charge because you’re setting the other side to -1, which is the charge of NO3-, not the charge of Fe(NO3)3, which is 0.</p>

<p>-1 (charge of NO3) = (-2 (charge of oxygen) * 3 oxygens) + (x (charge of nitrogen) * 1 nitrogen)</p>

<p>-1 = (-6) + x
x = 5</p>

<p>Na2HPO4</p>

<p>-2 (charge of HPO4) = (-2 (charge of oxygen) * 4 oxygens) + (1 (charge of hydrogen) * 1 hydrogen) + (x (charge of phosphorus) * 1 phosphorus)</p>

<p>-2 = -8 + 1 + x
x = 5
-1 = (-6) + x
x = 5</p>

<p>Ahhh so put in short, when calculating the ox.# of a non-oxygen element w/in a polyatomic ion, you disregard the cation it reacts with?</p>

<p>Exactly :D</p>

<p>anyone know just how much easier PR is? and if its substantially easier, what are better practice tests (I only have 1 or 2 past tests)?</p>

<p>I have both PR and Cliffnotes, and the latter’s practice tests seem substantially harder, but also look less likely to be like the real thing…in one there are over 5 organic questions.</p>

<p>Where can I get past multiple choice sections from??? I’ve been looking endlessly and I cant find any.</p>

<p>Please PM me telling me how to get any or if you have them</p>

<p>^ I would like to know where you would find them as well.</p>

<p>To those asking for past exams–I have 2008, which I got from my teacher, but my scanner’s not working and I’m not typing it up. Perhaps I’ll just go through and give you guys some questions to try answering.</p>

<ol>
<li>What is the molality of a solution of phosphoric acid, H3PO4, that contains 24.5 g of phosphoric acid (molar mass 98.0 g) in 100. g of H2O?
a) 0.245 m
b) 2.50 m
c) 4.00 m
d) 25.0 m
e) 40.0 m</li>
</ol>

<p>Practice doing it without your calculator, since you wouldn’t get your calculator for the MC.</p>

<ol>
<li>H2(g) + I2(g) <–> 2HI(g) delta H is greater than 0
Which of the following changes to the equilibrium system represented above will increase the quantity of HI(g) in the equilibrium mixture?</li>
</ol>

<p>I. adding H2(g)
II. Increasing temp
III. decreasing pressure</p>

<p>a) I only
b) III only
c) I and II only
d) II and III only
e) I, II, III</p>

<p>Nonexistant-</p>

<ol>
<li><p>b?</p></li>
<li><p>c?</p></li>
</ol>

<p>Do you know where your teacher got the 2008 practice mult. choice from?</p>

<p>Wags–Yep!</p>

<p>I think you’d be able to order it from the collegeboard store, where you can usually buy released exams…though, since the exam’s Tuesday, it might be too late for that.</p>

<ol>
<li><p>Of the following single bonds, which is the LEAST polar?
a) N-H
b) H-F
c) O-F
d) I-F
e) O-H</p></li>
<li><p>Which of the following molecules has an angular (bent) geometry that is commonly represented as a resonance hybrid of two or more electron-dot structures?
a) CO2
b) O3
c) CH4
d) BeF2
e) OF2</p></li>
</ol>

<p>29.
B, .25 mol H3PO4/.1 kg = 2.5 m</p>

<p>35.
C, adding H2 will cause a shift to the left - increases HI. Increasing temperature (since it is endothermic) will cause a shift to the left as well.</p>

<p>71.
C, closest to each other on periodic table</p>

<p>75.
B</p>

<ol>
<li><p>c?</p></li>
<li><p>a?</p></li>
</ol>

<p>thanks for doing this!</p>

<p>35) c? 29) b</p>

<p>non-existent</p>

<p>73.d?</p>

<p>75.b?</p>

<p>My answers of C and B are correct. I can explain why if there is any confusion.</p>

<p>NewAccount got it.</p>

<p>darn…</p>