AP Chem Equation Sheet: What Is on It and How to Use It

Yes, you get an equation sheet on the AP Chemistry exam, along with a periodic table, and you can use both on the multiple-choice and free-response sections. The sheet covers the core quantitative relationships in the course, organized by topic. What it does not do is tell you when to use each equation, what the variables mean in context, or how to reason through a problem, and that is where most points are won or lost.

Here is what is on the sheet, what you still need to know cold, and how to practice with it so it saves you time instead of costing it.

What is on the AP Chemistry equation sheet?

The official reference packet includes a periodic table, a page of equations and constants grouped by topic, and a key to symbols and abbreviations. The groupings follow the big quantitative areas of the course.

Constants such as Planck's constant, the speed of light, Avogadro's number, the gas constant in several units, and Faraday's constant appear on the sheet, so you do not need to memorize their values.

College Board posts the current reference packet on AP Central, and it is also available in the Bluebook test preview. Download it now and use the exact version you will see on test day.

What is NOT on the AP Chem equation sheet?

This is the list that matters most. The sheet gives you formulas, not chemistry.

Concepts and definitions you must know

• Stoichiometry fundamentals: mole ratios, limiting reactant, percent yield, and percent composition.
• Empirical and molecular formulas: how to get from mass data to a formula.
• Hess's law: how to combine reactions and their enthalpy changes.
• Bond enthalpy reasoning: energy is absorbed to break bonds and released when bonds form.
• Periodic trends: atomic radius, ionization energy, and electronegativity, plus the explanations based on Coulomb's law and shielding.
• Intermolecular forces: how London dispersion, dipole-dipole, and hydrogen bonding explain boiling points, vapor pressure, and solubility.
• Solubility basics: the AP course expects you to know that common salts of sodium, potassium, ammonium, and nitrate are soluble.

Interpretation the sheet will not give you

• Sign conventions: what a negative ΔG°, a positive ΔS°, or a positive E° means for a reaction.
• K versus Q: how to predict which way a reaction shifts. Our guide to AP Chemistry equilibrium covers this in depth.
• Graphical kinetics: which plot is linear for zero, first, and second order reactions. The integrated rate laws are on the sheet, but knowing that a straight ln[A] versus time plot means first order is on you.
• Buffers: the Henderson-Hasselbalch equation is provided, but you need to recognize a buffer and know that pH equals pKa at the half-equivalence point of a titration.

How do you use the equation sheet on exam day?

Students who use the sheet well treat it as a checklist, not a textbook. Here is a process that works on both sections.

1. Identify the topic before you look at the sheet. Read the question and decide whether it is kinetics, equilibrium, thermodynamics, and so on. That tells you which section to scan.
2. List your knowns with units. Writing "T = 298 K, ΔH° = −92 kJ/mol" makes the right equation obvious.
3. Match the equation to the variables you have. Find the equation that contains your knowns and the one unknown you need.
4. Check units before you plug in. The most common error is mixing joules and kilojoules, especially in ΔG° = ΔH° − TΔS°, where entropy is usually given in J/(mol·K) and enthalpy in kJ/mol.
5. Pick the right gas constant. The sheet lists R in more than one set of units. Use the one in joules for energy equations and the one in L·atm for gas law problems.
6. Show the setup on free-response questions. Readers often award points for a correct setup with numbers substituted, even before the final answer.

Worked example: free energy and spontaneity

Suppose a reaction has ΔH° = −92 kJ/mol and ΔS° = −199 J/(mol·K). Is it thermodynamically favorable at 298 K?

1. Convert entropy to kJ: −199 J/(mol·K) = −0.199 kJ/(mol·K).
2. Use ΔG° = ΔH° − TΔS° from the sheet.
3. ΔG° = −92 − (298)(−0.199) = −92 + 59.3 = −32.7 kJ/mol.
4. Since ΔG° is negative, the reaction is thermodynamically favorable at 298 K.

The equation was on the sheet. The unit conversion and the interpretation were not. That pattern repeats across the whole exam.

How should you study with the equation sheet?

The best time to learn the sheet is months before the exam, not the night before.

1. Print it and use it on every problem set. You want to know where each equation lives so you find it in seconds.
2. Annotate a practice copy. Next to each equation, write when it applies and one common trap. You cannot bring this copy into the exam, but making it builds the habits you need.
3. Practice released free-response questions with the sheet in hand. AP Central posts past questions and scoring guidelines. Our AP Chem FRQ guide explains how points are awarded on each question type.
4. Drill the "not on the sheet" list separately. Flashcards work well for periodic trends, intermolecular forces, and sign conventions.
5. Time yourself. If you are still hunting for equations in timed practice, you have not used the sheet enough.

Do you need to memorize anything on the sheet?

Strictly, no. But students who score well usually know the most common equations by heart anyway, simply from using them. That fluency matters on the multiple-choice section, which has 60 questions in 90 minutes.

Calculators are permitted on the AP Chemistry exam. Check the College Board calculator policy for approved models, and practice with the exact calculator you will bring.

How the equation sheet fits into your score

Because the sheet levels the playing field on formulas, the exam rewards conceptual reasoning and clean problem-solving. That is why strong students still miss points: they find the right equation but misread units or skip the explanation.

To see how your practice-test results translate into a projected score, try the AP Chemistry score calculator. Cutoffs vary by year, so use it as an estimate. For a full study plan, read how to get a 5 on AP Chemistry.

How Ivystar can help

Ivystar tutors teach you how to read a chemistry problem, pull the right relationship from the sheet, and explain your reasoning the way AP readers want to see it. Our AP Exam Prep program pairs you with tutors from schools like Harvard, Penn, and MIT, and it comes with our "Get an A or we work for free" class-grade guarantee. Book a free strategy call to get started.