Honestly, the 2024 AP Chemistry FRQ felt like a fever dream for a lot of students. You walk into that gym or classroom, smelling like stale floor wax and anxiety, and suddenly you’re staring at a particulate diagram that looks more like modern art than science. It happens every year. But 2024? It had some specific teeth.
The College Board released the questions shortly after the May exam, and the collective sigh (or scream) from the Reddit r/APStudents community was deafening. It wasn't just that the math was tedious. It was the way they phrased the conceptual stuff. If you didn't know your IMF (intermolecular forces) cold, or if you stumbled on the titration curve nuances, you were basically toast.
The Beast of Question 1: Solubility and Thermodynamics
Question 1 is usually the "warm-up," but 2024 didn't play nice. It focused heavily on the solubility of lead(II) fluoride ($PbF_2$). Right out of the gate, they’re asking for the $K_{sp}$ expression. Simple, right? But then they throw in the temperature dependence.
Students often forget that $K_{sp}$ is temperature-dependent because the dissolution process is either endothermic or exothermic. In this specific case, the $2024$ exam pushed students to justify why solubility increases with temperature using the sign of $\Delta H$. If you didn't mention that breaking the lattice energy requires more energy than is released by hydration—or at least link it to Le Chatelier’s principle—you lost points. It’s that "justify your answer" part that kills. It’s not enough to be right; you have to prove why you aren't wrong.
The Titration Curve That Wouldn't End
Titrations are the bread and butter of AP Chem, but the 2024 AP Chemistry FRQ featured a weak acid-strong base titration that required a really specific understanding of the buffer region. Specifically, the half-equivalence point.
You’ve probably heard it a thousand times: $pH = pK_a$ at the half-equivalence point. But the 2024 prompt asked students to identify the species present at different stages. A lot of kids just guess "ions." No. You had to specify that before the equivalence point, you have a mixture of the weak acid and its conjugate base.
What's wild is how many people missed the particulate drawing part. They give you a box and tell you to draw what’s in the beaker. If you drew five $OH^-$ ions when the acid was still in excess, you just handed those points back to the College Board. It’s about conservation of mass and charge. It’s about looking at the molecules and seeing them move.
Kinetics: The Part Everyone Hates
Let's talk about Question 3. Kinetics. Everyone thinks they’re good at kinetics until they have to derive a rate law from a mechanism with a fast initial step. The 2024 FRQ included a mechanism involving $NO_2$ and $CO$.
If the first step is fast and reversible, you have to use the steady-state approximation or the equilibrium method to substitute the intermediate out of the rate law. You can't have an intermediate in your final rate law. Period. It's a rule. Yet, every year, thousands of students leave $[NO_3]$ or some other transient species in there. The 2024 graders were looking for that substitution. They wanted to see that you knew the intermediate's concentration depends on the reactants that formed it.
The Surprise of Beer’s Law
One of the shorter questions involved spectrophotometry. It seemed easy. Use $A = \epsilon bc$. But the twist was a common lab error scenario. "A student forgets to wipe the fingerprint off the cuvette."
Think about it. A fingerprint scatters light. If the detector sees less light, it thinks the solution absorbed more light. Therefore, the calculated concentration is erroneously high. This is the kind of "real-world" chemistry that the 2024 AP Chemistry FRQ loved to poke at. It wasn't just "plug numbers into a formula." It was "tell me how a smudge of thumb grease ruins your whole week in the lab."
Thermodynamics and the Entropy Trap
The 2024 exam really leaned into $\Delta S$. They gave a reaction where a solid turned into a gas. Easy, right? Entropy increases. But then they asked about the "magnitude" of the change.
I saw a lot of students get confused between $\Delta G = \Delta H - T\Delta S$ and the simple sign of the variables. In 2024, there was a heavy emphasis on whether a reaction is enthalpy-driven or entropy-driven. If $\Delta H$ is positive (endothermic) and the reaction is spontaneous, it must be entropy-driven. The $T\Delta S$ term has to be large enough to outweigh the positive $\Delta H$. This logic chain is the "gold standard" for a 5 on the exam.
Lewis Structures and Formal Charge
You'd think by May, everyone can draw a Lewis structure. Nope. The 2024 FRQ threw a molecule at students that had multiple valid resonance structures. The question wasn't "draw it," but rather "which one is the most likely?"
This is where formal charge comes in. The best structure is the one where formal charges are closest to zero, or where the negative charge sits on the most electronegative atom (looking at you, Oxygen and Fluorine). If you just drew a structure that satisfied the octet rule and moved on, you missed the nuance.
How to Use the 2024 FRQ for Future Study
If you're looking at these questions to prepare for next year, don't just look at the answer key. Look at the Scoring Guidelines. The College Board is very specific. They often require a "claim, evidence, and reasoning" format even if they don't explicitly say those words.
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- Claim: The reaction is endothermic.
- Evidence: The equilibrium constant $K$ increases as temperature increases.
- Reasoning: According to Le Chatelier’s principle, an increase in temperature favors the endothermic direction to consume the added heat.
If you miss any of those three, you’re likely getting a 0 or a 1 instead of a 2 on that part.
The "Calculated" Risks
The math in the 2024 FRQ wasn't computationally impossible, but the significant figures were a trap. If the burette reading is given as $12.45$ mL, and you round your final answer to $12$ mL, you're losing a point. AP Chemistry is one of the few places where "close enough" isn't actually close enough. You need to track those digits like a hawk.
Also, the unit for $R$ in $PV=nRT$ ($0.08206$) vs the $R$ in $\Delta G = -RT \ln K$ ($8.314$). People swapped those constantly in 2024. Use the wrong $R$, get a nonsensical energy value, and suddenly your $\Delta G$ is in the millions of Joules.
Final Practical Steps for Mastery
To really get the most out of the 2024 AP Chemistry FRQ data, you should follow a specific workflow. Don't just read the questions; do them under a timer. 15 minutes for a long question, 7 minutes for a short one.
- Print the un-marked PDF. You can find this on the College Board’s AP Central site.
- Write your answers in ink. No erasing. This forces you to commit to your logic.
- Grade yourself ruthlessly. If the scoring guideline says "must mention IMF," and you only said "the molecules stick together," do not give yourself the point.
- Analyze the "Chief Reader Report." This is a document released later in the year where the head grader explains exactly where students messed up. It's a gold mine for avoiding common pitfalls.
- Redo the missed sections. Wait three days, then try the exact same question again. If you can't get it right a second time, you don't actually understand the concept yet; you just remembered the answer.
The 2024 exam proved that the College Board is moving away from rote memorization. They want to see if you can think like a chemist in a messy, smudged-cuvette kind of world. Focus on the why behind the what, and the 2025 or 2026 exam won't feel nearly as intimidating as 2024 did for the thousands of students who sat in those creaky wooden chairs last May.