**OFFICIAL** AP Chemistry 2013 Thread

<p>Wait sorry I did 6A ii. For 6B, alchohols are soluble in water and because Compound 2 is soluble in water and Box X is an alcohol, they match.</p>

<p>@collegedreams</p>

<p>For 5.b, you had to note that initially there will be more moles of reactants (HCl added), but as the temperature is raised, the reaction progresses and product is formed, which reduces the number of moles and thus the pressure in the container.</p>

<p>Hopefully they can read my handwriting after that god-awful time limit.</p>

<p>Anyone know how to do 2a ?</p>

<p>For 2.a., you calculate the moles of Al, and multiply by the mol of electron to mol of Al ratio, which is 3/1. The answer is 26.1 moles of electrons I think.</p>

<p>@collegedreams29…that’s what I put</p>

<p>@FlyingWombat I think I misunderstood the question so I did it wrong O.O</p>

<p>@engarde</p>

<p>I finished like 10 minutes early and had no idea what to do with my time…My problem wasn’t time…it was just the weirdness of some of the qs</p>

<p>Are we allowed to talk about the multiple choice now? we should compile a list like last year.</p>

<p>Here are the first 4 problems with solutions. I’m not 100% sure about 2.d.</p>

<p>[Question</a> 1 | ExtraZoom High Definition image #3997. Zoom in or zoom out high resolution photo.](<a href=“http://extrazoom.com/image-3997.html]Question”>http://extrazoom.com/image-3997.html)
[Question</a> 2 | ExtraZoom High Definition image #3998. Zoom in or zoom out high resolution photo.](<a href=“http://extrazoom.com/image-3998.html]Question”>http://extrazoom.com/image-3998.html)
[Question</a> 3 | ExtraZoom High Definition image #3999. Zoom in or zoom out high resolution photo.](<a href=“http://extrazoom.com/image-3999.html]Question”>http://extrazoom.com/image-3999.html)
[Question</a> 4 | ExtraZoom High Definition image #4000. Zoom in or zoom out high resolution photo.](<a href=“http://extrazoom.com/image-4000.html]Question”>http://extrazoom.com/image-4000.html)</p>

<p>Sorry, uploading them took a long time because I wanted high quality images.</p>

<p>For 2.a, balance half reactions then figure out 235g Al -> moles of Al -> moles of electrons.</p>

<p>What kind of graph did you guys draw for 6(e)? I just drew a graph that was exothermic (i.e. ending state lower than starting state), but only one activation energy bump. I marked that the transition state was the C2H5+ and Cl- on the graph. Does that make sense?</p>

<p>I have a doubt, my paper was entirely different from the one uploaded , so will there be TWO curves in this AP exam? or the curve will be same for both?</p>

<p>I am not quite sure of your solutions in number one killerskullz, but I may be wrong. Why did you divide 1.2x10 to the whatever in A(iii), the 100ml at that point should not matter.</p>

<p>Could rxn 2 be this:
CO2+H2O —> H+ + HCO3-</p>

<p>Because H2CO3 dissociates
Is that also a valid answer?</p>

<p>@killerskullz</p>

<p>Thanks for those! I (and others, too!) appreciate it.</p>

<p>@superstarlala</p>

<p>H2CO3 is not a strong acid, so it shouldn’t disassociate
However, they might accept it. Let’s wait till the actual solutions come out</p>

<p>@Squikii </p>

<p>We’re never allowed to speak of the mcqs…unless they are released</p>

<p>^ agree. noticed some rubrics take more than 1 answer for question 4 so it may work.</p>

<p>shoot I butchered number 1 and 3</p>

<p>@darkaeroga, because you need to plug in Molarity into the Ksp equation, not mols. 1.2 was the mols, and 0.1 was the Liters, so molarity was 1.2/.1.</p>

<p>anyone work out the last two yet?</p>

<p>@superstarlala, H2CO3 would ONLY dissociate into H2O and CO2, so I’m afraid not :&lt;/p>