If you want to see a pre-med student flinch, just whisper "Question 3" in their ear. Seriously. The 2017 AP Chem FRQ is legendary in the world of high school science, and not because it was particularly fun. It was a brutal wake-up call for anyone who thought they could just memorize their way through the curriculum.
Back in May 2017, thousands of students walked into gyms and cafeterias, opened those shrink-wrapped booklets, and met their match. It wasn't just about the math. It was about the logic. The College Board shifted the vibe that year. They moved away from "plug these numbers into $PV = nRT$" and toward "tell me why this molecule actually behaves like this." Honestly, if you can master the concepts from this specific exam, you're basically halfway to a 5 on any modern chemistry test.
What Actually Happened with the 2017 AP Chem FRQ?
The 2017 set was a mix of classic stoichiometry and some really weird, context-heavy problems. It had seven questions total. Three long ones, four short ones.
Question 1 started off innocently enough with some Mg-Al alloy chemistry. But then it hit people with a gravimetric analysis twist. You had to account for the mass of a precipitate and justify why a student’s experimental result might be too high. This is where the 2017 AP Chem FRQ really separated the kids who "know" chemistry from the kids who "do" chemistry. If you didn't understand that a wet precipitate adds mass—and therefore inflates your calculated moles—you were toast.
The Problem with Particulate Diagrams
One thing that caught everyone off guard was the emphasis on drawing. You’d think by 11th or 12th grade you’re done with art class, but the College Board had other plans. In Question 3, they asked for a representation of $CS_2$ and $O_2$ reacting.
Most people mess this up. They forget to count the atoms. If you start with four oxygen atoms on the left, you better have four on the right, even if they're tucked into different molecules. It's the Law of Conservation of Mass, but in picture form. It sounds easy until you’re thirty minutes into a three-hour exam and your brain is starting to turn into soup.
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The Thermodynamics Trap in Question 2
Question 2 focused on $COCl_2$, or phosgene. It’s a nasty gas, and the math wasn't much better. This question was a masterclass in Equilibrium and Thermodynamics.
Students had to calculate $K_p$ from $K_c$. Usually, you just use the formula $K_p = K_c(RT)^{\Delta n}$. Simple, right? Well, only if you remember that $\Delta n$ is the change in the number of moles of gas. If you didn't check the states of matter in the equation, you were dead in the water. The 2017 AP Chem FRQ loved these little "gotcha" moments.
Then came the entropy. $\Delta S$.
You had to explain why the entropy increased. Most kids wrote "there are more moles of gas." That’s fine. But the College Board wanted more. They wanted you to talk about the increase in microstates or the greater dispersal of matter. It’s that nuance that turns a 3 into a 4.
Why Question 3 Was a Nightmare
I mentioned Question 3 earlier, but we need to talk about the $CS_2$ combustion. This was the long question that broke people. It asked for a Lewis structure of $CS_2$. Okay, fine. Double bonds on both sides of the Carbon. Linear geometry. $180^\circ$ bond angle.
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But then they asked about the intermolecular forces.
A lot of students saw the Sulfur and thought "Polar!" They assumed it had dipole-dipole forces. Nope. $CS_2$ is linear and symmetrical. The dipoles cancel out. It only has London Dispersion Forces (LDFs). If you missed that, every subsequent part of the question—the boiling point comparison, the vapor pressure—was wrong. It's a domino effect.
Chromatography and the "Art" of Chemistry
Question 5 was a short one, but it was weird. It dealt with paper chromatography.
You had to identify which dye was most polar based on how far it traveled up the paper using a specific solvent. This is one of those labs that some teachers skip because it's "too simple." But on the 2017 AP Chem FRQ, it was worth significant points.
If the solvent is polar and the dye travels far, the dye is polar. Like dissolves like. It’s the golden rule of chemistry. Yet, in the heat of the moment, people flip it. They think the "heavy" dye stays at the bottom. It’s not about weight; it’s about affinity. It’s about who the dye wants to hang out with more: the paper or the liquid.
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The Big Takeaways for Your Study Sessions
Looking back at this exam, several patterns emerge that are still relevant for the current AP Chem format.
- Units will kill you. Seriously. If you’re doing a Gibbs Free Energy calculation ($\Delta G = \Delta H - T\Delta S$), your $\Delta H$ is usually in kilojoules while your $\Delta S$ is in joules. If you don't convert one of them, your answer will be off by a factor of 1000. The 2017 AP Chem FRQ was notorious for this.
- Justify everything. Don’t just give a "yes" or "no" answer. Use the "claim, evidence, reasoning" (CER) framework.
- Significant figures matter. You usually get one "sig fig" point per exam. Don’t throw it away because you were too lazy to count decimal places.
- The Periodic Table is your best friend. Not for the names, but for the trends. Electronegativity, atomic radius, ionization energy—know why they happen (effective nuclear charge), not just that they happen.
How to Practice the 2017 AP Chem FRQ Today
Don't just read the answer key. That's the biggest mistake you can make. You'll read it and think, "Oh yeah, that makes sense." Of course it makes sense; the person who wrote the key has a PhD.
Instead, set a timer for 15 minutes for a short question and 23 minutes for a long one. Sit in a quiet room. No phone. No music. Just a calculator and the periodic table.
When you're done, use the official scoring guidelines from the College Board. Be mean to yourself. If you didn't use the specific keyword they asked for, don't give yourself the point. This "tough love" approach is the only way to actually improve.
The 2017 AP Chem FRQ isn't just a relic of the past. It's a blueprint. It shows exactly how the College Board likes to weave together different units—like putting thermodynamics inside an equilibrium problem. If you can navigate the 2017 exam, you've developed the "chemical intuition" needed to handle whatever they throw at you this year.
Next Steps for Mastery
- Download the PDF. Go to the College Board website and print the 2017 FRQ. Yes, print it. Physical paper hits different when you're practicing.
- Focus on Question 3. Spend extra time on the $CS_2$ problem. It covers bonding, geometry, and IMFs—three pillars of the course.
- Check the Chief Reader Report. This is a secret weapon. The Chief Reader writes a report every year explaining exactly where students messed up. Read the 2017 report to see the common pitfalls.
- Re-draw the particulate diagrams. If your drawings don't match the key perfectly, figure out why. Is it the number of molecules? The spacing? The orientation?
Chemistry is a language. The FRQs are just long-form essays written in that language. Start practicing the 2017 set today, and you'll be speaking "5" by the time May rolls around.