My 2023 AP Chemistry Free-Response DRAFT ANSWERS are linked at the bottom of this post. Please let the know where I have made errors and typos, and I will be happy to amend.
Again, this is a staggeringly simple examination for what is supposed to be the gold standard in US, high school chemistry education. Of course, many children will struggle with it but that is absolutely not a function of the difficulty of the exam, but rather a continued function of the fact that thousands and thousands of kids that have absolutely no business taking AP Chemistry are still be placed in the course for nefarious, and cosmetic reasons. The perception of achievement still outweighs actual achievement; it’s the modern way. The utter obsession with particulate diagrams continues – we know why, someone is drinking the ‘research’ Kool-Aid.
On to the questions themselves.
Question 1
(a)(i) I believe that if the question says, ‘complete’, that noble gas core representations should not be accepted. Of course, they will be.
(ii) A much better way to ask this question is to ask for the electronic configuration of a positive ion. That way it asks the orbital, and tests if the student knows electrons should be removed.
(b)-(e) I don’t know if the CB/TDC thinks that this type of question is ‘testing lab work’, but if they do they are grossly mistaken. This is a typical example of a stoichiomtery problem that has no relationship to anything that may (or may not) have gone on in the lab during the year. for the BILLIONTH time, if you want to test lab work, have a lab exam.
(d) It’s staggering to me that more teachers don’t say something like, “all formulae are simply the ratio of the moles of the components’. In my experience that helps a lot.
(f)(iv) In my answer I didn’t say, ‘conservation of mass’, but I think that you could as long as you say, ‘sealed’ or ‘nothing can escape’ with it.
Question 2
(b) I don’t know why the question uses the words, “using reactions 2, 3 and 4”. Shouldn’t we leave it up to the student to work out what to do? Seems like too much spoon-feeding to me, but this is a common issue of course.
(c)(ii) I suppose that as long as this is worth only 1 point, then the approx. x and y values for the trough will be enough (with a similar shape), but I do worry that if it were worth more points then there could be some subtleties associated with the starting and finish positions of the curve. I suspect (hope) that I am overthinking this a bit.
(d)(i) and (ii) Lots more interesting questions could be asked around those diagrams. Resonance? Actual bond angles?
Question 3
(a) Such a shame that equation writing has been decimated in the modern exam. Why give the full equation? This is sad.
(e) At least this is a stoichometry question that has some depth. I’d have love to have seen a back titration instead, but those days are gone forever I fear.
(g) Why give the total mass? I’d prefer making that part of the question.
Question 4
(b) Again, if anyone thinks this is sufficiently testing lab work, then they are nuts!
(c) Very lame. SO much more you can do with buffer calculations. Yes, I know it’s only for 1 point here, but buffers! It’s the one place that really strong kids can distinguish themselves.
Question 5
(a)(i) What would an AP exam be without P V = n R T??
(ii) Eighth grade physical science class.
(c) Imagine a prickly Ka calculation here instead! Oh for rigor!
Question 6
(a) Why do we have a table?
(c) Quite a lot of stuff on bond length overall on the exam, a bit of an odd topic to emphasize.
Question 7
(a) I would like an alternative answer to say that some associated ionic formula units should be shown since the presence of a Ksp suggests a relative lack of solubility. Yes I know the question says “ions present” but those ions could associated too.
(b)(i) The level of hand holding is shocking here, asking the first part of the calculation prior to (b)(ii). Oh well …
(c) Why not a common ion calculation instead?
Question 6 b i. I think that hydrogen bonds must be mentioned as the source of the difference in heat of vaporization. The prompt says “TYPES and relative strengths.” We’ll see in a couple of weeks how it is graded!
Fair comment, but I’d likely argue that since LDFs and DD are mentioned for both compounds earlier, then H-bonding must be the difference (and I know we have the problem of different magnitudes of LDF and DD).
I had a World Chem. Olympiad Gold Medalist in my class this year. He had one of the unreleased versions. He commented that his version was easier than the released version. Sad. I wonder if students who get 5s should bother taking the credit…they are liable to get crushed in college if this is benchmark for master of gen chem.
Spot on!
Thanks Dan!
#2 c – Should the graph start to the right since Al is larger than Cl? I am thinking the credit on that part may hinge on the starting point. Thoughts?
Well, that’s the question that I am posing above! It’s hard to know what level of detail (if any) is going to be required beyond the new position of the trough.
I’ve taken a bit of a break from paying attention to the AP exam, but this year I had a bunch of kids take it, so I got the FRQs and did my answers. I always come here for a second check on my work and for the entertaining commentary.
Like you, I was stunned at how easy this test has become. I remember thinking when I did #4a that the question was confusing and needlessly wordy and then realized that if they’re going to remove all the rigor, posing a reading challenge is the only way they’re going to get statistical spread on the scores.
Unfortunately, I will have students who will get a 4 on this thing and think they’ve accomplished something. It’s nearly impossible to learn anything when you refuse to read, refuse to pay attention in lecture and only do half the homework problems, but that’s mostly who’s in our classes now. And, of course, the hours and hours of obligatory lab work we do in class is entirely irrelevant to this exam, as you’ve pointed out a thousand times.
You’ve nailed the type of kid that tends to turn up in AP classes these days, which is of course a function of the wrong kids being pushed into AP classes and the subsequent colossal decrease in rigor. As for “obligatory” lab work, there’s no audit police you know?!
This was another sad excuse for a college-level chemistry exam. With all of the “depth of understanding and rigor” that the questions are supposed to elicit, the test-writers had students apply an ideal conditions gas law to a (polar molecule) HCl sample at ~room temperature and almost 8 atm of pressure. Absurd.
This is a great point re: conditions, John. It’s such an odd question.