AP Chemistry · Science
AP Chemistry: free lessons and course outline
College-level chemistry (atomic structure, bonding, intermolecular forces, stoichiometry, kinetics, thermochemistry, equilibrium, acids and bases, and electrochemistry) taught unit by unit to the College Board framework, with the calculations and the particle-level explanations the exam asks for. Exam format from 2027: this is a hybrid digital exam: multiple choice in Bluebook, free response handwritten in a paper booklet. Work the practice problems on paper and check your steps against the worked answer, the way you will sit the free-response section in May.
AP Chemistry follows the nine units of the College Board course framework. Unit 3 (properties of substances and mixtures) and Unit 8 (acids and bases) carry the most weight, and nearly every free-response question asks you to connect a calculation to a particle-level explanation: the lessons below practice both halves every time.
- U1Atomic Structure and Properties7–9%
- U2Compound Structure and Properties7–9%
- U3Properties of Substances and Mixtures18–22%
- U4Chemical Reactions7–9%
- U5Kinetics7–9%
- U6Thermochemistry7–9%
- U7Equilibrium7–9%
- U8Acids and Bases11–15%
- U9Thermodynamics and Electrochemistry7–9%
Every lesson, unit by unit
U1 is free to read below. The other units open with a free month or a paid plan.
U1 Atomic Structure and Properties 7–9% of the examFREE
U2 Compound Structure and Properties 7–9% of the exam
- 2.1 Types of chemical bonds
- 2.2 Potential energy, bond length and bond strength
- 2.3 Structure of ionic solids, metals and alloys
- 2.4 Lewis diagrams
- 2.5 Resonance and formal charge
- 2.6 VSEPR, molecular shape and hybridization
U3 Properties of Substances and Mixtures 18–22% of the exam
- 3.1 Intermolecular and interparticle forces
- 3.2 Properties of solids, liquids and gases
- 3.3 The ideal gas law and partial pressures
- 3.4 Kinetic molecular theory and real gases
- 3.5 Solutions, molarity and particle diagrams
- 3.6 Separating mixtures and solubility
- 3.7 Spectroscopy and the properties of photons
- 3.8 The Beer-Lambert law
U4 Chemical Reactions 7–9% of the exam
- 4.1 Physical and chemical changes
- 4.2 Balanced and net ionic equations
- 4.3 Particulate representations of reactions
- 4.4 Stoichiometry
- 4.5 Introduction to titration
- 4.6 Types of chemical reactions
- 4.7 Introduction to acid-base reactions
- 4.8 Oxidation-reduction reactions and half-reactions
U5 Kinetics 7–9% of the exam
- 5.1 Reaction rates
- 5.2 Introduction to rate law
- 5.3 Concentration changes over time
- 5.4 Elementary reactions and the collision model
- 5.5 Reaction energy profiles
- 5.6 Mechanisms and the rate law
- 5.7 The pre-equilibrium approximation
- 5.8 Multistep reaction energy profiles
- 5.9 Catalysis
U6 Thermochemistry 7–9% of the exam
- 6.1 Endothermic and exothermic processes
- 6.2 Heat transfer, heat capacity and calorimetry
- 6.3 Energy of phase changes
- 6.4 Enthalpy of reaction
- 6.5 Bond enthalpies
- 6.6 Enthalpy of formation
- 6.7 Hess's law
U7 Equilibrium 7–9% of the exam
- 7.1 Introduction to equilibrium
- 7.2 The reaction quotient and the equilibrium constant
- 7.3 The size of K and how K changes with the equation
- 7.4 Calculating equilibrium concentrations
- 7.5 Le Chatelier's principle
- 7.6 Solubility equilibria and Ksp
- 7.7 The common-ion effect
U8 Acids and Bases 11–15% of the exam
- 8.1 Introduction to acids and bases: pH and Kw
- 8.2 pH and pOH of strong acids and bases
- 8.3 Weak acid and base equilibria
- 8.4 Acid-base reactions and mixtures
- 8.5 Acid-base titrations
- 8.6 Molecular structure of acids and bases
- 8.7 pH, pKa and the Henderson-Hasselbalch equation
- 8.8 Buffers and buffer capacity
- 8.9 pH and solubility
U9 Thermodynamics and Electrochemistry 7–9% of the exam
- 9.1 Entropy
- 9.2 Gibbs free energy and thermodynamic favorability
- 9.3 Free energy, equilibrium and dissolution
- 9.4 Coupled reactions
- 9.5 Galvanic and electrolytic cells
- 9.6 Cell potential and free energy
- 9.7 Cell potential under nonstandard conditions
- 9.8 Electrolysis and Faraday's law
Keep going in the full AP Chemistry course
All of U1 (Atomic Structure and Properties) is free to everyone, with no account. The course has 69 lessons, each with worked examples and practice problems that come with full solutions. A free account can also start a free month of the whole course, with no card.
Open this lesson in the courseSee the whole course