For AP students

AP Chemistry study hub

Chem Help is organized by concept, not by exam. This page re-frames the same lessons and question bank into the 9 College Board AP Chemistry units so you can study, check coverage, and practice the way the exam is structured.

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What the exam looks like

Updated for the 2026–27 AP year

Hybrid digital: complete multiple-choice questions and view free-response questions in Bluebook, then handwrite free-response answers in paper exam booklets.

Calculators are allowed on both sections. Scientific or graphing calculators are permitted, and Bluebook provides built-in Desmos scientific and graphing calculators.

Official source: AP Chemistry exam details · College Board calculator policy

Section I — Multiple choice

60 questions · 90 minutes · 50% of the score. Calculator allowed.

Section II — Free response

7 questions (3 long, 4 short) · 105 minutes · 50% of the score. Calculator allowed.

Provided on exam day

Periodic table, formula sheet, and constants. You still need fluency with the reasoning.

Exam format and unit weightings follow College Board. The official sources above and below are authoritative; always confirm current details there.

The 9 AP units, mapped to Chem Help

Each card lists the College Board topics for that AP unit and the Chemistry Help units and topics that cover them. Some AP units pull from more than one Chem Help unit, which is normal: our units are sequenced for learning, the AP units are sequenced for the exam.

Topics Chem Help teaches that are not part of the AP course (for example, Graham’s law of effusion and the van der Waals equation) are excluded from this map, from AP question counts, and from AP practice sets. You can still practice them in standard mode.

AP Unit 1: Atomic Structure and Properties

Moles and molar mass, elemental composition, mass spectra, electron configurations, photoelectron spectroscopy, and periodic trends.

7–9% of exam

Mapped Chem Help content

Stoichiometry · Periodic Trends · Bonding

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College Board topics

1.1 Moles and Molar Mass
1.2 Mass Spectroscopy of Elements
1.3 Elemental Composition of Pure Substances
1.4 Composition of Mixtures
1.5 Atomic Structure and Electron Configuration
1.6 Photoelectron Spectroscopy
1.7 Periodic Trends
1.8 Valence Electrons and Ionic Compounds

Where to study it here

Stoichiometry
Definition of the mole/Mole conversions · Percent composition · Empirical formula
Periodic Trends
Electronegativity ionization energy atomic radius · Shielding/Electron Orbital structure
Bonding
Electron orbitals

AP Unit 2: Compound Structure and Properties

Bond types and bond energy, ionic and metallic solids, Lewis diagrams, resonance and formal charge, VSEPR geometry, and hybridization.

7–9% of exam

Mapped Chem Help content

Molecular Structure · Bonding · Types of Solids and IMFs

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College Board topics

2.1 Types of Chemical Bonds
2.2 Intramolecular Force and Potential Energy
2.3 Structure of Ionic Solids
2.4 Structure of Metals and Alloys
2.5 Lewis Diagrams
2.6 Resonance and Formal Charge
2.7 VSEPR and Bond Hybridization

Where to study it here

Molecular Structure
Lewis structures · Octet rule · Formal Charge
Bonding
VSEPR · Hybridization · Sigma and Pi bonds
Types of Solids and IMFs
Types of elements · Solids

AP Unit 3: Properties of Substances and Mixtures: Intermolecular Forces

Intermolecular forces, states of matter, the ideal gas law and KMT, solutions and separations, and spectroscopy including Beer's law.

18–22% of exam

Mapped Chem Help content

Types of Solids and IMFs · Gases, Solutions & Spectroscopy

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College Board topics

3.1 Intermolecular and Interparticle Forces
3.2 Properties of Solids
3.3 Solids, Liquids, and Gases
3.4 Ideal Gas Law
3.5 Kinetic Molecular Theory
3.6 Deviation from Ideal Gas Law
3.7 Solutions and Mixtures
3.8 Representations of Solutions
3.9 Separation of Solutions and Mixtures: Chromatography
3.10 Solubility
3.11 Spectroscopy and the Electromagnetic Spectrum
3.12 Photoelectric Effect
3.13 Beer-Lambert Law

Where to study it here

Types of Solids and IMFs
Intro to IMFS · Justification with IMFS · Lab: Paper & Thin-Layer Chromatography of Dyes
Gases, Solutions & Spectroscopy
Ideal Gas Law, Dalton's Law & Gas Stoichiometry · Kinetic Molecular Theory & Speed Distributions · Solutions, Mixtures & Chromatography · Beer's Law Spectroscopy

AP Unit 4: Chemical Reactions

Net ionic equations, physical vs. chemical change, reaction stoichiometry, titrations, precipitation, acid-base, and redox reactions.

7–9% of exam

Mapped Chem Help content

Stoichiometry · Chemical Reactions

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College Board topics

4.1 Introduction for Reactions
4.2 Net Ionic Equations
4.3 Representations of Reactions
4.4 Physical and Chemical Changes
4.5 Stoichiometry
4.6 Introduction to Titration
4.7 Types of Chemical Reactions
4.8 Introduction to Acid-Base Reactions
4.9 Oxidation-Reduction (Redox) Reactions

Where to study it here

Stoichiometry
Balancing Chemical Equations · Mole ratios/Mass to mass stoichiometry · Limiting reagents · Percent yield · Lab: Hydrate Analysis & Gravimetric Thermal Decomposition
Chemical Reactions
Net Ionic Equations & Precipitation Reactions · Solution Stoichiometry & Gravimetric Analysis · Acid-Base Neutralization & Proton Transfer · Oxidation Numbers & Identifying Redox Reactions · Balancing Redox Reactions · Lab: Gravimetric Analysis of Precipitation · Lab: Oxidation-Reduction Titration (KMnO₄)

AP Unit 5: Kinetics

Reaction rates, rate laws, integrated rate laws, collision theory, mechanisms and rate-determining steps, and catalysis.

7–9% of exam

Mapped Chem Help content

Chemical Kinetics

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College Board topics

5.1 Reaction Rates
5.2 Introduction to Rate Law
5.3 Concentration Changes Over Time
5.4 Elementary Reactions
5.5 Collision Model
5.6 Reaction Energy Profile
5.7 Introduction to Reaction Mechanisms
5.8 Reaction Mechanism and Rate Law
5.9 Steady-State Approximation
5.10 Multistep Reaction Energy Profile
5.11 Catalysis

Where to study it here

Chemical Kinetics
Reaction Rates & Differential Rate Laws · Integrated Rate Laws & Half-Life · Collision Theory & Arrhenius Equation · Elementary Steps & Reaction Mechanisms

AP Unit 6: Thermodynamics

Energy transfer, calorimetry and heat capacity, enthalpy of reaction, bond enthalpies, enthalpies of formation, and Hess's law.

7–9% of exam

Mapped Chem Help content

Thermochemistry & Thermodynamics

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College Board topics

6.1 Endothermic and Exothermic Processes
6.2 Energy Diagrams
6.3 Heat Transfer and Thermal Equilibrium
6.4 Heat Capacity and Calorimetry
6.5 Energy of Phase Changes
6.6 Introduction to Enthalpy of Reaction
6.7 Bond Enthalpies
6.8 Enthalpy of Formation
6.9 Hess's Law

Where to study it here

Thermochemistry & Thermodynamics
Heat Transfer, Specific Heat & Calorimetry · Bond Dissociation Energies & Enthalpy of Reaction · Hess's Law & Standard Enthalpies of Formation · Lab: Coffee-Cup Calorimetry & Heat of Reaction

AP Unit 7: Equilibrium

Reversible reactions, Q vs. K, ICE-table calculations, Le Châtelier's principle, solubility equilibria, and the common-ion effect.

7–9% of exam

Mapped Chem Help content

Chemical Equilibrium & Solubility

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College Board topics

7.1 Introduction to Equilibrium
7.2 Direction of Reversible Reactions
7.3 Reaction Quotient and Equilibrium Constant
7.4 Calculating the Equilibrium Constant
7.5 Magnitude of the Equilibrium Constant
7.6 Properties of the Equilibrium Constant
7.7 Calculating Equilibrium Concentrations
7.8 Representations of Equilibrium
7.9 Introduction to Le Châtelier's Principle
7.10 Reaction Quotient and Le Châtelier's Principle
7.11 Introduction to Solubility Equilibria
7.12 Common-Ion Effect
7.13 pH and Solubility
7.14 Free Energy of Dissolution

Where to study it here

Chemical Equilibrium & Solubility
Equilibrium Constant & Reaction Quotient Q vs K · ICE Tables & Equilibrium Calculations · Le Chatelier's Principle & System Shifts · Solubility Product K_sp & Common Ion Effect · Lab: Spectrophotometric Equilibrium Constant Determination

ICE Table Practice

Build initial–change–equilibrium tables and check each equilibrium step as you work.

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AP Unit 8: Acids and Bases

pH and pOH, weak acid and base equilibria, titration curves and indicators, buffers, and the Henderson-Hasselbalch equation.

11–15% of exam

Mapped Chem Help content

Acids, Bases & Aqueous Equilibria

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College Board topics

8.1 Introduction to Acids and Bases
8.2 pH and pOH of Strong Acids and Bases
8.3 Weak Acid and Base Equilibria
8.4 Acid-Base Reactions and Buffers
8.5 Acid-Base Titrations
8.6 Molecular Structure of Acids and Bases
8.7 pH and pK_a
8.8 Properties of Buffers
8.9 Henderson-Hasselbalch Equation
8.10 Capacity of Buffers

Where to study it here

Acids, Bases & Aqueous Equilibria
pH, pOH, K_w & Strong Acid-Base Calculations · Weak Acids, Weak Bases, K_a/K_b & Salt Hydrolysis · Acid-Base Titration Curves & Chemical Indicators · Buffer Solutions & Henderson-Hasselbalch Equation

Titration Curve Explorer

See buffer, half-equivalence, and equivalence regions change as titrant volume changes.

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AP Unit 9: Applications of Thermodynamics

Entropy and Gibbs free energy, thermodynamic favorability, free energy and equilibrium, galvanic and electrolytic cells, and electrolysis.

7–9% of exam

Mapped Chem Help content

Thermochemistry & Thermodynamics · Electrochemistry & Applications of Thermodynamics

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College Board topics

9.1 Introduction to Entropy
9.2 Absolute Entropy and Entropy Change
9.3 Gibbs Free Energy and Thermodynamic Favorability
9.4 Thermodynamic and Kinetic Control
9.5 Free Energy and Equilibrium
9.6 Coupled Reactions
9.7 Galvanic (Voltaic) and Electrolytic Cells
9.8 Cell Potential and Free Energy
9.9 Cell Potential Under Nonstandard Conditions
9.10 Electrolysis and Faraday's Law

Where to study it here

Thermochemistry & Thermodynamics
Entropy, Gibbs Free Energy & Thermodynamic Favorability
Electrochemistry & Applications of Thermodynamics
Galvanic Cells & Standard Reduction Potentials · Cell Potential, Gibbs Free Energy & Equilibrium Constant · Nernst Equation & Concentration Cells · Electrolytic Cells & Faraday's Law Calculations

A simple AP study loop

Step 1
Take the diagnostic at the AP level to find weak skills.
Step 2
Work the mapped Chem Help units and lessons for the AP unit you are on.
Step 3
Build a timed AP practice set and review every explanation.

Official College Board resources

For exam format, scoring, and released questions, the official pages below are the authoritative source.

2027 AP Chemistry exam details

College Board, AP Students

Official 2027 exam timing, section structure, hybrid digital testing information, and calculator guidance.

Open the 2027 AP Chemistry exam details on AP Students

AP calculator policy

College Board, AP Central

Official calculator rules for AP Chemistry, including the Bluebook built-in Desmos calculators.

Open College Board's AP calculator policy

Past exam questions & scoring guidelines

College Board, AP Central

Official released free-response questions with scoring guidelines and sample responses, so you can see exactly how AP Chemistry answers are graded.

Open past AP Chemistry exam questions on AP Central

Official course framework & exam description

College Board, AP Central

The authoritative AP Chemistry course and exam description: unit structure, science practices, lab requirements, and exam format.

Open the AP Chemistry course framework on AP Central

Student course overview & exam dates

College Board, AP Students

The student-facing overview: what the course covers, how the exam is structured, exam dates, and score information.

Open the AP Chemistry student overview on AP Students

Disclaimer: Chem Help is an independent educational project and is not affiliated with or endorsed by College Board. AP and Advanced Placement are trademarks registered by the College Board, which does not sponsor or endorse this site. Chem Help links to official College Board pages; it does not reproduce copyrighted AP exam questions.