The 9 units of AP Chemistry
Each unit has a study guide with the key ideas, equations and common mistakes, and a set of practice questions with explanations.
Atomic Structure and Properties
Counting atoms with the mole, reading mass spectra and photoelectron spectra, and explaining periodic trends with Coulomb's law.
- Moles and molar mass
- Mass spectroscopy of elements
- Elemental composition of pure substances
- Composition of mixtures
- Atomic structure and electron configuration
- Photoelectron spectroscopy
- Periodic trends
- Valence electrons and ionic compounds
Compound Structure and Properties
Why atoms bond the way they do, and how to predict the shape and polarity of a molecule from its Lewis diagram.
- Types of chemical bonds
- Intramolecular force and potential energy
- Structure of ionic solids
- Structure of metals and alloys
- Lewis diagrams
- Resonance and formal charge
- VSEPR and bond hybridization
Properties of Substances and Mixtures
The largest unit on the exam: intermolecular forces, gases, solutions and how light interacts with matter.
- Intermolecular forces
- Properties of solids
- Solids, liquids and gases
- Ideal gas law
- Kinetic molecular theory
- Deviation from ideal gas law
- Solutions and mixtures
- Representations of solutions
- Separation of solutions and mixtures (chromatography)
- Solubility
- Spectroscopy and the electromagnetic spectrum
- Photoelectric effect
- Beer-Lambert law
Chemical Reactions
Writing net ionic equations, doing stoichiometry with confidence, and the first look at titrations, acid-base and redox reactions.
- Introduction for reactions
- Net ionic equations
- Representations of reactions
- Physical and chemical changes
- Stoichiometry
- Introduction to titration
- Types of chemical reactions
- Introduction to acid-base reactions
- Oxidation-reduction (redox) reactions
Kinetics
How fast reactions go, how to find a rate law from data, and what a mechanism tells you.
- Reaction rates
- Introduction to rate law
- Concentration changes over time
- Elementary reactions
- Collision model
- Reaction energy profile
- Introduction to reaction mechanisms
- Reaction mechanism and rate law
- Steady-state approximation
- Multistep reaction energy profile
- Catalysis
Thermochemistry
Tracking heat: calorimetry, phase changes and three ways to find the enthalpy change of a reaction.
- Endothermic and exothermic processes
- Energy diagrams
- Heat transfer and thermal equilibrium
- Heat capacity and calorimetry
- Energy of phase changes
- Introduction to enthalpy of reaction
- Bond enthalpies
- Enthalpy of formation
- Hess's law
Equilibrium
Reversible reactions, the equilibrium constant, ICE tables and predicting shifts.
- Introduction to equilibrium
- Direction of reversible reactions
- Reaction quotient and equilibrium constant
- Calculating the equilibrium constant
- Magnitude of the equilibrium constant
- Properties of the equilibrium constant
- Calculating equilibrium concentrations
- Representations of equilibrium
- Introduction to Le Chatelier's principle
- Reaction quotient and Le Chatelier's principle
- Introduction to solubility equilibria
- Common-ion effect
- pH and solubility
- Free energy of dissolution
Acids and Bases
pH of strong and weak acids and bases, titration curves and buffers. The second-largest unit on the exam.
- Introduction to acids and bases
- pH and pOH of strong acids and bases
- Weak acid and base equilibria
- Acid-base reactions and buffers
- Acid-base titrations
- Molecular structure of acids and bases
- pH and pKa
- Properties of buffers
- Henderson-Hasselbalch equation
- Buffer capacity
Thermodynamics and Electrochemistry
Entropy and free energy decide whether a process is favorable. Electrochemistry puts that free energy to work.
- Introduction to entropy
- Absolute entropy and entropy change
- Gibbs free energy and thermodynamic favorability
- Thermodynamic and kinetic control
- Free energy and equilibrium
- Coupled reactions
- Galvanic (voltaic) and electrolytic cells
- Cell potential and free energy
- Cell potential under nonstandard conditions
- Electrolysis and Faraday's law
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