AP Chemistry
772 indexed practice questions across 9 units. Open a unit for a summary and question list with links to full explanations.
easy 321medium 357hard 94
Units
- Unit 1: Atomic Structure and Properties93 questions
- Unit 2: Molecular and Ionic Compound Structure and Properties94 questions
- Unit 3: Intermolecular Forces and Properties83 questions
- Unit 4: Chemical Reactions90 questions
- Unit 5: Kinetics86 questions
- Unit 6: Thermodynamics81 questions
- Unit 7: Equilibrium75 questions
- Unit 8: Acids and Bases91 questions
- Unit 9: Applications of Thermodynamics79 questions
AP Chemistry Universal Cheatsheet
Key Vocabulary
Molarity: mol solute / L solution
Limiting reactant: consumed first; sets product yield
Empirical formula: simplest whole-number atom ratio
Ionization energy: energy to remove an electron (gaseous atom)
Electronegativity: atom's pull on shared electrons
Formal charge: valence − (lone e⁻ + ½ bonded e⁻)
Resonance: delocalized electrons; bond order is averaged
London dispersion: induced-dipole force; grows with molar mass
STP: 0 °C, 1 atm; 22.4 L/mol
Rate law: rate = k[A]ᵐ[B]ⁿ; orders from experiment, not coefficients
Activation energy (Ea): energy barrier; catalyst lowers it
Hess's Law: ΔH path-independent; sum steps
Le Chatelier: equilibrium shifts to relieve the applied stress
Buffer: weak acid + conjugate base resists pH change
Gibbs free energy: ΔG° = ΔH° − TΔS°; negative = thermodynamically favored
Cell potential: E°cell = E°cathode − E°anode; ΔG° = −nFE°
Critical Concepts
- • PES peaks: lower binding energy = valence (farther from nucleus); peak height = number of electrons in the subshell
- • Periodic trends: IE/EN increase across a period and up a group; atomic radius does the opposite
- • VSEPR: lone pairs compress angles: CH₄ 109.5° → NH₃ 107° → H₂O 104.5°
- • Hybridization: sp³ = tetrahedral, sp² = trigonal planar, sp = linear
- • Ideal gas: PV = nRT; real gases deviate most at high P and low T
- • Integrated rate laws: 0th: [A] = [A]₀ − kt · 1st: ln[A] = ln[A]₀ − kt · 2nd: 1/[A] = 1/[A]₀ + kt
- • Equilibrium: solids and pure liquids never appear in K; K changes only with temperature
- • pH = pKa: at the half-equivalence point of a titration; [HA] = [A⁻]
- • ΔG° = −RT ln K: K > 1 ↔ ΔG° < 0; K < 1 ↔ ΔG° > 0
Exam Tips
- • Always label units on every FRQ calculation: units are free points
- • Net ionic equations: cancel spectator ions, keep charges balanced
- • When in doubt about equilibrium direction, compare Q to K
- • ΔG° = −nFE°: use n = moles of electrons transferred, not moles of metal
- • FRQ: claim + evidence + reasoning. Cite data from the prompt, then the principle
AP Chemistry FAQ
›How many AP Chemistry practice questions does Apentix have?
772 questions across 9 units: every question includes a full explanation and is tagged by difficulty (easy, medium, hard).
›Are these questions like the real AP Chemistry exam?
Yes, questions follow College Board's unit weighting and format for AP Chemistry, including stimulus-based and standalone multiple choice with AP-style distractors.
›Is it free?
Yes. Browsing questions, unit guides, and cheatsheets is free; a free account adds progress tracking, assignments, and classroom games.