AP Chemistry Study Guide
All 9 units of the AP Chemistry course, with the topics College Board lists for each and a short summary of what the unit covers.
Units at a glance
| Unit | Multiple-choice weighting |
|---|---|
| Unit 1: Atomic Structure and Properties | 7-9% |
| Unit 2: Compound Structure and Properties | 7-9% |
| Unit 3: Properties of Substances and Mixtures | 18-22% |
| Unit 4: Chemical Reactions | 7-9% |
| Unit 5: Kinetics | 7-9% |
| Unit 6: Thermochemistry | 7-9% |
| Unit 7: Equilibrium | 7-9% |
| Unit 8: Acids and Bases | 11-15% |
| Unit 9: Thermodynamics and Electrochemistry | 7-9% |
Weightings are College Board's ranges for the multiple-choice section.
Unit 1: Atomic Structure and Properties
7-9% of the multiple-choice section
This unit starts with the atomic theory of matter and uses the mole to connect the mass of a sample you can weigh to the number of particles in it. You will write electron configurations, read mass spectra and photoelectron spectroscopy data, and explain periodic trends in terms of atomic structure. These ideas about atoms are the base for every later unit.
Topics in this unit
- Moles and Molar Mass
- Mass Spectra of Elements
- Elemental Composition of Pure Substances
- Composition of Mixtures
- Atomic Structure and Electron Configuration
- Photoelectron Spectroscopy
- Periodic Trends
- Valence Electrons and Ionic Compounds
Shaky on any of these? Paste your class notes for Unit 1 into the free flashcard maker or the free quiz maker.
Unit 2: Compound Structure and Properties
7-9% of the multiple-choice section
Unit 2 connects the arrangement of atoms, ions, and molecules, and the chemical bonds between them, to the properties of a substance you can observe. You will use electronegativity to predict the type of bond between two atoms and study the structure of ionic solids, metals, and alloys. You will also draw Lewis diagrams and use resonance, formal charge, VSEPR, and hybridization to describe molecules.
Topics in this unit
- 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 Hybridization
Shaky on any of these? Paste your class notes for Unit 2 into the free flashcard maker or the free quiz maker.
Unit 3: Properties of Substances and Mixtures
18-22% of the multiple-choice section
This is the most heavily weighted unit. It explains the properties of solids, liquids, and gases through how orderly their particles are, how freely they move, and how strongly they attract each other. You will work with the ideal gas law, kinetic molecular theory, and the ways real gases deviate from ideal behavior, then move on to solutions, solubility, and separating mixtures. The unit ends with spectroscopy, the properties of photons, and the Beer-Lambert law.
Topics in this unit
- Intermolecular and Interparticle 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
- Solubility
- Spectroscopy and the Electromagnetic Spectrum
- Properties of Photons
- Beer-Lambert Law
Shaky on any of these? Paste your class notes for Unit 3 into the free flashcard maker or the free quiz maker.
Unit 4: Chemical Reactions
7-9% of the multiple-choice section
Unit 4 moves from physical changes to chemical changes, which make and break chemical bonds and produce new substances with different properties. You will write and balance chemical equations, including net ionic equations, and use stoichiometry to find how much product a reaction can form. You will also meet titration and sort reactions into types such as acid-base and oxidation-reduction (redox).
Topics in this unit
- 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
Shaky on any of these? Paste your class notes for Unit 4 into the free flashcard maker or the free quiz maker.
Unit 5: Kinetics
7-9% of the multiple-choice section
Kinetics is about how fast chemical reactions happen and what changes that speed, including reactant concentration, temperature, and catalysts. You will measure rates by tracking concentration over time, write rate laws, and use the collision model and reaction energy profiles to explain them. You will also connect multistep reaction mechanisms to the rate law and study how catalysts work.
Topics in this unit
- 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
- Pre-Equilibrium Approximation
- Multistep Reaction Energy Profile
- Catalysis
Shaky on any of these? Paste your class notes for Unit 5 into the free flashcard maker or the free quiz maker.
Unit 6: Thermochemistry
7-9% of the multiple-choice section
This unit covers the energy that goes into or comes out of physical and chemical processes, with conservation of energy as the central idea. You will classify processes as endothermic or exothermic, measure heat with calorimetry, and find the energy of phase changes. A key point is that breaking a bond always takes an energy input, while forming one releases energy, which you will use with bond enthalpies, enthalpies of formation, and Hess’s law.
Topics in this unit
- 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
Shaky on any of these? Paste your class notes for Unit 6 into the free flashcard maker or the free quiz maker.
Unit 7: Equilibrium
7-9% of the multiple-choice section
Chemical equilibrium is a dynamic state where the forward and reverse reactions run at the same rate. You will write and calculate the equilibrium constant K, compare it with the reaction quotient Q, and use Le Châtelier’s principle to predict how a system shifts when concentration, temperature, or volume changes. The unit also treats dissolving a solid as an equilibrium, including the common-ion effect.
Topics in this unit
- 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 Châtelier’s Principle
- Reaction Quotient and Le Châtelier’s Principle
- Introduction to Solubility Equilibria
- Common-Ion Effect
Shaky on any of these? Paste your class notes for Unit 7 into the free flashcard maker or the free quiz maker.
Unit 8: Acids and Bases
11-15% of the multiple-choice section
Unit 8 applies equilibrium to acid-base chemistry, where proton-exchange reactions are reversible and reach equilibrium quickly. You will calculate pH and pOH for strong and weak acids and bases, analyze titrations, and relate an acid's molecular structure to its strength. Buffers get extended attention, including the Henderson-Hasselbalch equation and buffer capacity, and the unit closes with how pH affects solubility.
Topics in this unit
- 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
- pH and Solubility
Shaky on any of these? Paste your class notes for Unit 8 into the free flashcard maker or the free quiz maker.
Unit 9: Thermodynamics and Electrochemistry
7-9% of the multiple-choice section
The final unit ties together ideas from Units 1 through 8 by using thermodynamics to predict the direction of changes in matter. You will work with entropy and Gibbs free energy to decide whether a reaction is thermodynamically favorable, and link free energy to the equilibrium constant. The last four topics cover electrochemistry: galvanic and electrolytic cells, cell potential, and electrolysis with Faraday’s law.
Topics in this unit
- Introduction to Entropy
- Absolute Entropy and Entropy Change
- Gibbs Free Energy and Thermodynamic Favorability
- Thermodynamic and Kinetic Control
- Free Energy and Equilibrium
- Free Energy of Dissolution
- Coupled Reactions
- Galvanic (Voltaic) and Electrolytic Cells
- Cell Potential and Free Energy
- Cell Potential Under Nonstandard Conditions
- Electrolysis and Faraday’s Law
Shaky on any of these? Paste your class notes for Unit 9 into the free flashcard maker or the free quiz maker.
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Source
Unit titles, weightings and topics are from College Board's AP Chemistry Course and Exam Description (Fall 2024). The unit summaries are ours. All AP study guides and score calculators.