How to study chemistry using active recall and problem practice

Chemistry is a problem-solving subject disguised as a memorization subject. Most students fail because they try to memorize formulas and reaction types instead of practicing solving problems. You cannot learn chemistry by reading. You learn it by working through calculations, balancing equations, and predicting products until the patterns become automatic. If your study session doesn't involve a pencil and scratch paper, you're wasting your time.

Why Chemistry is hard to study

Chemistry operates on three levels simultaneously, and your brain has to juggle all of them: the macroscopic (what you see, like color changes, gas bubbles, precipitates), the symbolic (chemical equations, formulas, mathematical relationships), and the particulate (what atoms and molecules are actually doing). Most students only study at the symbolic level. They memorize formulas and balance equations, but exam questions constantly ask you to move between levels. "Why does this reaction produce heat?" requires particulate thinking about bond energies. "What would you observe?" requires connecting symbols to macroscopic changes. On top of this, chemistry is cumulative in a brutal way. If you don't understand moles and stoichiometry deeply, you cannot do equilibrium. If you can't do equilibrium, acids and bases are impossible. Every gap compounds.

Common mistakes students make studying Chemistry

Reading worked examples without solving them yourself. Looking at a solved stoichiometry problem and thinking "yeah, that makes sense" is not learning. Cover the solution, attempt the problem, fail, then study why you failed. That struggle is the learning.
Memorizing formulas without understanding what they represent. Knowing PV = nRT is useless if you can't explain what happens to pressure when you halve the volume at constant temperature, and WHY that happens at the molecular level.
Studying organic chemistry by memorizing reaction names instead of practicing mechanisms. You need to be able to push electrons through a mechanism from scratch, not recognize the name "SN2" on a flashcard. Draw the mechanism. Every time.
Ignoring dimensional analysis and significant figures until exam week. These aren't decoration. They're how you catch errors. Students who skip unit tracking make calculation mistakes they never catch.

How to actually study Chemistry

Chemistry studying should be at least 70% problem-solving. Here's how to structure it. For conceptual topics (atomic structure, bonding, thermodynamics), start by reading the material once for understanding. Then close the book and try to explain the concept to yourself, out loud or in writing, as if teaching someone else. Can you explain why ionic compounds have high melting points using intermolecular forces? If you get stuck, you've found your gap. For calculation-heavy topics (stoichiometry, equilibrium, electrochemistry), do problems. Lots of them. Start with textbook examples: cover the solution, attempt the problem, then check. When you get one wrong, don't just read the correct solution. Redo the problem from scratch after understanding the error. Build a collection of problem types you struggle with and revisit them with spaced intervals. Lexie can help here: photograph your problem sets and it'll turn them into practice questions with built-in spacing. For reaction chemistry (predicting products, mechanisms, acid-base), practice predicting before revealing answers. Given reactants and conditions, what products form? What mechanism applies? Write your prediction, then check. The prediction-then-feedback loop is far more effective than reading reaction tables. For laboratory connections, mentally walk through procedures. What would you observe at each step? Why do you add reagents in that order? These visualization exercises prepare you for practical questions.

Example study session: 45 minutes

Minutes 0–5: Without opening any notes, write down the key equations and concepts from your last lecture on chemical equilibrium. Le Chatelier's principle. Can you state it and give three specific examples of how changing conditions shifts equilibrium? Write first, check second. Minutes 5–25: Work through 6 equilibrium problems of increasing difficulty. Start with "given Kc, find equilibrium concentrations" (ICE table practice). Progress to "how does adding more reactant affect the position of equilibrium and the value of K?" Write complete solutions including units. No peeking at formulas. Minutes 25–35: Switch to a spaced review topic, like stoichiometry from two weeks ago. Solve 3 limiting reagent problems. If you can do them quickly and correctly, you're maintaining that knowledge. If you struggle, flag these for more frequent review. Minutes 35–45: Review every problem you got wrong. For each error, identify whether it was conceptual (didn't understand the principle) or procedural (made a math/setup error). Redo the conceptual errors from scratch. Write down the specific mistake so you recognize the pattern next time.

Key facts

Students who solve practice problems score 67% higher than those who only review notes (Karpicke & Blunt, 2011)
Chemistry courses have the highest DFW (D/Fail/Withdraw) rates in STEM at 25–35%
Problems requiring multi-level thinking (macro-symbolic-particulate) are missed by 70% of students
Students who practice retrieval retain 2.5x more after one week than those who reread

Frequently asked questions

Practice, not memorization. Start with simple equations and balance them by inspection. Adjust coefficients one element at a time, leaving hydrogen and oxygen for last. Once basic balancing is automatic, move to redox balancing using the half-reaction method. The key is repetition: balance 10 equations per study session until it becomes second nature. Flashcard apps like Lexie that show you unbalanced equations and ask for coefficients are excellent for this.

Don't memorize the whole thing. That's a waste of time. But you should know the first 20 elements, their symbols, and approximate atomic masses. More importantly, understand the trends: electronegativity increases across a period and up a group, atomic radius does the opposite. Knowing WHY these trends exist (effective nuclear charge) is more useful than memorizing numbers. You'll naturally learn common elements through repeated problem-solving.

Draw mechanisms, not flashcards. Organic chemistry is about electron movement. Nucleophiles attack electrophiles, leaving groups leave. For each reaction type, practice drawing the full mechanism with curved arrows showing electron flow. Start from reactants and predict products by following the electrons. Do this on blank paper without notes. If you can push electrons through a mechanism from scratch, you understand the reaction. If you can only recognize the reaction name, you don't.

Because understanding and recall are different cognitive processes. In class, the information is presented to you, so recognition is easy. On an exam, you must produce the information from memory and apply it to novel problems. The fix: stop rereading notes and start solving problems without help. Every study session should feel harder than class. If it doesn't, you're building familiarity, not the retrieval strength you need for exams.

Turn your notes into practice questions in seconds

Lexie uses active recall and spaced repetition to help you actually remember what you study. Snap a photo of your notes and get instant practice.

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