Marlbridge guide to AP® Chemistry

Unit roadmap

Units and topics exactly as numbered in the 2026–27 Course and Exam Description. Weightings are the official multiple-choice ranges. Marlbridge has written resources for 91 of 91 topics so far; the rest are planned and marked as such.

1. Unit 1: Atomic Structure and Properties 7–9% of multiple choice · 8 topics

   • 1.1 Moles and Molar Mass Study guideRevision notesPractice questionsTopic checklist
   • 1.2 Mass Spectra of Elements Study guideRevision notesPractice questionsTopic checklist
   • 1.3 Elemental Composition of Pure Substances Study guideRevision notesPractice questionsTopic checklist
   • 1.4 Composition of Mixtures Study guideRevision notesPractice questionsTopic checklist
   • 1.5 Atomic Structure and Electron Configuration Study guideRevision notesPractice questionsTopic checklist
   • 1.6 Photoelectron Spectroscopy Study guideRevision notesPractice questionsTopic checklist
   • 1.7 Periodic Trends Study guideRevision notesPractice questionsTopic checklist
   • 1.8 Valence Electrons and Ionic Compounds Study guideRevision notesPractice questionsTopic checklist
   • Atomic Structure and Properties: Unit Diagnostic (Chemistry Unit 1)
   • Atomic Structure and Properties: Mixed Unit Review (Chemistry Unit 1)
2. Unit 2: Compound Structure and Properties 7–9% of multiple choice · 7 topics

   • 2.1 Types of Chemical Bonds Study guideRevision notesPractice questionsTopic checklist
   • 2.2 Intramolecular Force and Potential Energy Study guideRevision notesPractice questionsTopic checklist
   • 2.3 Structure of Ionic Solids Study guideRevision notesPractice questionsTopic checklist
   • 2.4 Structure of Metals and Alloys Study guideRevision notesPractice questionsTopic checklist
   • 2.5 Lewis Diagrams Study guideRevision notesPractice questionsTopic checklist
   • 2.6 Resonance and Formal Charge Study guideRevision notesPractice questionsTopic checklist
   • 2.7 VSEPR and Hybridization Study guideRevision notesPractice questionsTopic checklist
   • Compound Structure and Properties: Unit Diagnostic (Chemistry Unit 2)
   • Compound Structure and Properties: Mixed Unit Review (Chemistry Unit 2)
3. Unit 3: Properties of Substances and Mixtures 18–22% of multiple choice · 13 topics

   • 3.1 Intermolecular and Interparticle Forces Study guideRevision notesPractice questionsTopic checklist
   • 3.2 Properties of Solids Study guideRevision notesPractice questionsTopic checklist
   • 3.3 Solids, Liquids, and Gases Study guideRevision notesPractice questionsTopic checklist
   • 3.4 Ideal Gas Law Study guideRevision notesPractice questionsTopic checklist
   • 3.5 Kinetic Molecular Theory Study guideRevision notesPractice questionsTopic checklist
   • 3.6 Deviation from Ideal Gas Law Study guideRevision notesPractice questionsTopic checklist
   • 3.7 Solutions and Mixtures Study guideRevision notesPractice questionsTopic checklist
   • 3.8 Representations of Solutions Study guideRevision notesPractice questionsTopic checklist
   • 3.9 Separation of Solutions and Mixtures Study guideRevision notesPractice questionsTopic checklist
   • 3.10 Solubility Study guideRevision notesPractice questionsTopic checklist
   • 3.11 Spectroscopy and the Electromagnetic Spectrum Study guideRevision notesPractice questionsTopic checklist
   • 3.12 Properties of Photons Study guideRevision notesPractice questionsTopic checklist
   • 3.13 Beer-Lambert Law Study guideRevision notesPractice questionsTopic checklist
   • Properties of Substances and Mixtures: Unit Diagnostic (Chemistry Unit 3)
   • Properties of Substances and Mixtures: Mixed Unit Review (Chemistry Unit 3)
4. Unit 4: Chemical Reactions 7–9% of multiple choice · 9 topics

   • 4.1 Introduction for Reactions Study guideRevision notesPractice questionsTopic checklist
   • 4.2 Net Ionic Equations Study guideRevision notesPractice questionsTopic checklist
   • 4.3 Representations of Reactions Study guideRevision notesPractice questionsTopic checklist
   • 4.4 Physical and Chemical Changes Study guideRevision notesPractice questionsTopic checklist
   • 4.5 Stoichiometry Study guideRevision notesPractice questionsTopic checklist
   • 4.6 Introduction to Titration Study guideRevision notesPractice questionsTopic checklist
   • 4.7 Types of Chemical Reactions Study guideRevision notesPractice questionsTopic checklist
   • 4.8 Introduction to Acid-Base Reactions Study guideRevision notesPractice questionsTopic checklist
   • 4.9 Oxidation-Reduction (Redox) Reactions Study guideRevision notesPractice questionsTopic checklist
   • Chemical Reactions: Unit Diagnostic (Chemistry Unit 4)
   • Chemical Reactions: Mixed Unit Review (Chemistry Unit 4)
5. Unit 5: Kinetics 7–9% of multiple choice · 11 topics

   • 5.1 Reaction Rates Study guideRevision notesPractice questionsTopic checklist
   • 5.2 Introduction to Rate Law Study guideRevision notesPractice questionsTopic checklist
   • 5.3 Concentration Changes Over Time Study guideRevision notesPractice questionsTopic checklist
   • 5.4 Elementary Reactions Study guideRevision notesPractice questionsTopic checklist
   • 5.5 Collision Model Study guideRevision notesPractice questionsTopic checklist
   • 5.6 Reaction Energy Profile Study guideRevision notesPractice questionsTopic checklist
   • 5.7 Introduction to Reaction Mechanisms Study guideRevision notesPractice questionsTopic checklist
   • 5.8 Reaction Mechanism and Rate Law Study guideRevision notesPractice questionsTopic checklist
   • 5.9 Pre-Equilibrium Approximation Study guideRevision notesPractice questionsTopic checklist
   • 5.10 Multistep Reaction Energy Profile Study guideRevision notesPractice questionsTopic checklist
   • 5.11 Catalysis Study guideRevision notesPractice questionsTopic checklist
   • Kinetics: Unit Diagnostic (Chemistry Unit 5)
   • Kinetics: Mixed Unit Review (Chemistry Unit 5)
6. Unit 6: Thermochemistry 7–9% of multiple choice · 9 topics

   • 6.1 Endothermic and Exothermic Processes Study guideRevision notesPractice questionsTopic checklist
   • 6.2 Energy Diagrams Study guideRevision notesPractice questionsTopic checklist
   • 6.3 Heat Transfer and Thermal Equilibrium Study guideRevision notesPractice questionsTopic checklist
   • 6.4 Heat Capacity and Calorimetry Study guideRevision notesPractice questionsTopic checklist
   • 6.5 Energy of Phase Changes Study guideRevision notesPractice questionsTopic checklist
   • 6.6 Introduction to Enthalpy of Reaction Study guideRevision notesPractice questionsTopic checklist
   • 6.7 Bond Enthalpies Study guideRevision notesPractice questionsTopic checklist
   • 6.8 Enthalpy of Formation Study guideRevision notesPractice questionsTopic checklist
   • 6.9 Hess’s Law Study guideRevision notesPractice questionsTopic checklist
   • Thermochemistry: Unit Diagnostic (Chemistry Unit 6)
   • Thermochemistry: Mixed Unit Review (Chemistry Unit 6)
7. Unit 7: Equilibrium 7–9% of multiple choice · 12 topics

   • 7.1 Introduction to Equilibrium Study guideRevision notesPractice questionsTopic checklist
   • 7.2 Direction of Reversible Reactions Study guideRevision notesPractice questionsTopic checklist
   • 7.3 Reaction Quotient and Equilibrium Constant Study guideRevision notesPractice questionsTopic checklist
   • 7.4 Calculating the Equilibrium Constant Study guideRevision notesPractice questionsTopic checklist
   • 7.5 Magnitude of the Equilibrium Constant Study guideRevision notesPractice questionsTopic checklist
   • 7.6 Properties of the Equilibrium Constant Study guideRevision notesPractice questionsTopic checklist
   • 7.7 Calculating Equilibrium Concentrations Study guideRevision notesPractice questionsTopic checklist
   • 7.8 Representations of Equilibrium Study guideRevision notesPractice questionsTopic checklist
   • 7.9 Introduction to Le Châtelier’s Principle Study guideRevision notesPractice questionsTopic checklist
   • 7.10 Reaction Quotient and Le Châtelier’s Principle Study guideRevision notesPractice questionsTopic checklist
   • 7.11 Introduction to Solubility Equilibria Study guideRevision notesPractice questionsTopic checklist
   • 7.12 Common-Ion Effect Study guideRevision notesPractice questionsTopic checklist
   • Equilibrium: Unit Diagnostic (Chemistry Unit 7)
   • Equilibrium: Mixed Unit Review (Chemistry Unit 7)
8. Unit 8: Acids and Bases 11–15% of multiple choice · 11 topics

   • 8.1 Introduction to Acids and Bases Study guideRevision notesPractice questionsTopic checklist
   • 8.2 pH and pOH of Strong Acids and Bases Study guideRevision notesPractice questionsTopic checklist
   • 8.3 Weak Acid and Base Equilibria Study guideRevision notesPractice questionsTopic checklist
   • 8.4 Acid-Base Reactions and Buffers Study guideRevision notesPractice questionsTopic checklist
   • 8.5 Acid-Base Titrations Study guideRevision notesPractice questionsTopic checklist
   • 8.6 Molecular Structure of Acids and Bases Study guideRevision notesPractice questionsTopic checklist
   • 8.7 pH and pKa Study guideRevision notesPractice questionsTopic checklist
   • 8.8 Properties of Buffers Study guideRevision notesPractice questionsTopic checklist
   • 8.9 Henderson-Hasselbalch Equation Study guideRevision notesPractice questionsTopic checklist
   • 8.10 Buffer Capacity Study guideRevision notesPractice questionsTopic checklist
   • 8.11 pH and Solubility Study guideRevision notesPractice questionsTopic checklist
   • Acids and Bases: Unit Diagnostic (Chemistry Unit 8)
   • Acids and Bases: Mixed Unit Review (Chemistry Unit 8)
9. Unit 9: Thermodynamics and Electrochemistry 7–9% of multiple choice · 11 topics

   • 9.1 Introduction to Entropy Study guideRevision notesPractice questionsTopic checklist
   • 9.2 Absolute Entropy and Entropy Change Study guideRevision notesPractice questionsTopic checklist
   • 9.3 Gibbs Free Energy and Thermodynamic Favorability Study guideRevision notesPractice questionsTopic checklist
   • 9.4 Thermodynamic and Kinetic Control Study guideRevision notesPractice questionsTopic checklist
   • 9.5 Free Energy and Equilibrium Study guideRevision notesPractice questionsTopic checklist
   • 9.6 Free Energy of Dissolution Study guideRevision notesPractice questionsTopic checklist
   • 9.7 Coupled Reactions Study guideRevision notesPractice questionsTopic checklist
   • 9.8 Galvanic (Voltaic) and Electrolytic Cells Study guideRevision notesPractice questionsTopic checklist
   • 9.9 Cell Potential and Free Energy Study guideRevision notesPractice questionsTopic checklist
   • 9.10 Cell Potential Under Nonstandard Conditions Study guideRevision notesPractice questionsTopic checklist
   • 9.11 Electrolysis and Faraday’s Law Study guideRevision notesPractice questionsTopic checklist
   • Thermodynamics and Electrochemistry: Unit Diagnostic (Chemistry Unit 9)
   • Thermodynamics and Electrochemistry: Mixed Unit Review (Chemistry Unit 9)

Exam skills

Guides that apply across every unit: what each task verb asks you to do, and how to set out answers so every step of your reasoning is visible.

• Explanations, Calculations and Representations: Exam Skills Guide (Chemistry)

  Write particle-level explanations that name a cause, set out multi-step calculations with units and significant figures, read and draw particulate diagrams, and back every claim with data.

• Task Verbs and Free-Response Technique: Exam Skills Guide (Chemistry)

  Learn what each free-response task verb in chemistry asks for, how much to write, how to plan the section's time and how to set out calculations, with original worked examples.

Science practices

1. Models and Representations

Describe models and representations, including across scales.

2. Question and Method

Determine scientific questions and methods.

3. Representing Data and Phenomena

Create representations or models of chemical phenomena. (Not assessed in multiple choice.)

4. Model Analysis

Analyze and interpret models and representations on a single scale or across multiple scales.

5. Mathematical Routines

Solve problems using mathematical relationships.

6. Argumentation

Develop an explanation or scientific argument.