Agh, I would chip in to finding the solutions, but I’m so tired and have a physics test to study for xD
To be honest I’m not sure what I want to major in. I definitely want to minor in astronomy, but I want to explore engineering and computer science before I decide my major. Maybe I might be an organic chemist if I ever like that.
After taking AP Chem, I basically have a love-hate relationship with it XD
And by the way, I have a question. For the question involving heat (recycling and extracting), I got an incorrect answer due to the fact that I forgot to add the molar heat (stated earlier, which should have been added after finding q). However, if I stated that recycling was the better solution and backed it up with that wrong answer, would I still receive credit?
Also there is A LOT of controversy concerning that titration graph. Some are saying the equiv point was at 9.23, but I was all like (DATS POH FEWL) and I was questioning the really steep downwards plunge. Could this mean that the substance is a terrible buffer?
The gaseous equilibrium one might have been easy for some, but I felt like that was such a curve ball… Kind of disappointed that I didn’t realize it now in hindsight.
@Dorfdude8 Awesome thanks! I was feeling pretty crappy about my FRQs but now that I’ve confirmed most of my answers I feel better as long as I didn’t bomb MC.
Haha I think a majority of AP Chem students want to major in engineering or something science-related because the course is simply so hard
@polarknut Same 
I was close in that I knew it had to do with Nernst but I just got it switched and thought Q would decrease leading to greater E
What did you all put for 2f?
(C2H4 was collected as a gas but C2H5OH was not. Explain in terms of IMFs between water and each of the 2 gases)
Well anyway here’s a breakdown of what I did wrong:
-Predicting what would happen to mass as cell worked and pressure for E. I completely forgot equilibrium, the nernst equation, and basic reasoning when I was doing this problem. I think I was suffering breakdown, and couldn’t concentrate till’ later in the test. -4 total
-I didn’t freaking see the f) part of the titration question until 15 seconds before the test was over. -2 for that one.
-Used 10^-4 instead of -3 with correct stoichiometry setup. -1 (I think)
-I usually like to dock 6 points in case I didn’t do good explaining on some parts or any parts that I’m unsure about. This is just for a worst case scenario. -6
Still a -13 and above 70%. Phew I think I’ll be fine XD Depending on my MC of course…
I said C2H5OH had hydrogen bonding so it’s IMFs were stronger than C2H4. I also explained how C2H5OH would be soluble with water so it would stay in solution while C2H4 would pass through as a gas.
@Dorfdude8 oh wait so did we figure out/guesstimate how much each problem was worth? I want to make a rough estimate of my FRQ score, but I don’t know how much each component was weighted.
@Ninjadu: I was on a time constraint, so I just said it was because C2H5OH consisted of more hydrogen bonds (which are stronger and more difficult to break). I feel like I could have something about the fact that water is polar and that C2H5OH was polar as well, but I’m half-asleep and can’t think of a proper response xD
@Ninjadu hydrogen bonding with water makes your ethyl alcohol (I think that’s what it is. Omg the IB Chem test I have next week will involve organic chem so I’d better nail this naming stuff down XD ) stuck dissolved in water and remains aqueous and not easily seperable. C2H4 is van der waals/LD forces, so it can separate from water, form weaker bonds between its constituent parts, and be a gas.
@nhnct21 Okay cool, that’s what I put too.
For the dissociation of Ca(OH)2 I labeled its state as aqueous instead of solid, since it was in water anyways. Does that matter? (I labeled the Ca2+ and OH- ions as aqueous also).
I didn’t sketch the entire titration curve because I though it only wanted it up to the equivalence point omg. How much will I be docked?
It said that Ca(OH)2 was a solid in the problem. That would make a difference since solids aren’t included in that solubility equation.
@Mochis1 Based on past exams, there are two ways you can get the points for IMF questions involving water. First, you can mention the hydrogen bonds with water, OR you can explain it in terms of polarity AS LONG as you mention either implicitly or explicitly that like dissolves like. Either way you explain it, that would get you 2 points.
Yes, but since it was dissolved in water anyways and I didn’t add an H2O to the reactant side, I labeled it as aqueous. Does that matter?
@Dorfdude8: Alright, I see. Thanks! I stated the reason due to the IMF, and I hope my explanation will get me those points (I’m hoping I was discrete enough).
@polarknut lemme try to scan the problems and make estimates right now
@Mochis1 how did you word it again, exactly?