A Guide to AP® Chemistry Units & Topics

AP® Chemistry Key Concepts

AP® Chemistry is one of the many science subjects the College Board® has to offer. In 2021, over 130,000 students worldwide took the AP Chemistry exam. The course is aimed to help high-school students develop a strong foundation in chemistry at the college level. Accordingly, you will study college-level chemistry, which encourages the learning of various core science practices and key theories that are vital to the further study of chemical sciences.

In this article, we’ll give you an overview of the units and topics in the AP Chemistry course, which are based on 6 science practices and 4 big ideas. This will give you a fair idea of what you will need to study to ace the AP Chemistry exam.

AP Chemistry Course Overview

The AP Chemistry course is made up of two main components — Science Practices and Course Content. As you progress through the course, you will learn the science practices because they are combined with the course content. These two main components of the AP Chemistry course are interdependent and will be a part of your study material right from the beginning.

The course content itself is broken down into separate units that will teach you an array of topics and concepts in AP Chemistry. These concepts are vital to a strong foundation in chemistry and are what colleges will expect you to master in order to qualify for college credit. Each unit in the course is based on one or more of the 4 big ideas of AP Chemistry. These ideas are nothing but the core concepts that play a key role in the study of chemistry.

The exam contains questions based on these units and science practices at different weights. You can read more about the exam in our AP Chemistry exam guide.

Now, let’s take a closer look at these two components, starting with the science practices.

What are the AP Chemistry Science Practices?

AP Chemistry has a total of six science practices that you will need to master. Simply put, they are skills that you will need to develop to study the various units in the course. Once learned, these skills will improve your critical thinking and analytical ability, which are necessary for further studies in chemistry and also key to doing well on the AP Chemistry exam. The science practices prescribed for this course are woven into each unit to help you learn and practice them better.

Here are the 6 science practices and the skills you will develop by mastering each of them.

  1. Models and Representations

    Through this science practice, you will develop the skills required to form detailed explanations of models and representations.

    Skills you will learn:

    1. Describe the components and quantitative information within models and representations that showcase properties at the particulate level.
    2. Describe the components and quantitative information within models and representations that showcase properties at both the particulate level and the macroscopic level.
  2. Question and Method

    This science practice will enable you to pose scientific questions and determine methods related to chemical procedures.

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Skills you will learn:

    1. Identify valid, testable scientific questions based on given data, observations, or models.
    2. Develop hypotheses or predictions based on experimental results.
    3. Identify procedures in a scientific experiment based on the developed questions.
    4. Make observations or gather data from hypothetical laboratory setups or experimental results.
    5. Identify areas of possible error in an experiment.
    6. Explain how alterations to an experiment might affect the results.
  1. Representing Data and Phenomena

    This science practice is related to the skill required to create representations of chemical phenomena.

    Skills you will learn:

    1. Use graphs with accurate scales and units to represent chemical phenomena.
    2. Create representations of chemical substances using models and diagrams.
    3. Visually represent relationships across different levels and scales, and between structures and interactions.
  2. Model Analysis

    Through this science practice, you will learn how to analyze models and representations, including their interpretation, both on a single scale and across multiple scales.

    Skills you will learn:

    1. Use chemical theories, representations, and models to describe the characteristics or phenomena of atoms and molecules.
    2. Study and justify whether a model is in agreement with chemical theories.
    3. Use models and representations to explain connections between particulate and macroscopic level properties of a substance.
    4. Study and explain how well a representation describes the relationship between particulate and macroscopic level properties.
  3. Mathematical Routines

    This science practice aims at developing your problem-solving skills using mathematical relationships.

    Skills you will learn:

    1. Identify quantities from the given information that can be used to solve a problem.
    2. Identify theories, definitions, and mathematical relationships that can be used to solve a given problem.
    3. Explain how changing one variable in an equation affects the other variables.
    4. Find and use the information provided in a graph to solve problems.
    5. Develop a balanced equation for a given chemical phenomena.
    6. Use logical computation pathways to predict or determine an unknown quantity from the given known quantities.
  4. Argumentation

    This science practice will enable you to think of and develop valid explanations or arguments of scientific nature with regard to a given chemical phenomenon.

    Skills you will learn:

    1. Make scientific claims.
    2. Use experimental data to support the developed claims.
    3. Use representations or models of particulate-level matter to support claims.
    4. Use chemical theories and mathematical routines to develop reasoning for the justification of claims.
    5. Identify relationships between particulate and macroscopic scales and use them to provide justification for claims.
    6. Explain how the result of a chemical experiment is dependent upon chemical processes and theories.
    7. Explain how possible sources of error within an experiment could affect the results.

AP Chemistry’s 4 Big Ideas

The big ideas are simply the themes that will be explored as you learn the content taught in the AP Chemistry topics. These big ideas provide the foundation on which the course is structured. The big ideas are interwoven into multiple units and therefore are applied in various contexts. Let’s take a look at each one of these big ideas.

In chemistry, quantities are described at the macroscopic as well as the atomic level. Understanding how to draw relationships between these quantities, within the same scale and across different scales, is vital to developing explanations and making predictions in chemistry.

The units you will study that further elaborate upon this big idea are: Atomic structure and properties, Intermolecular forces and properties, Chemical reactions, and Application of thermodynamics.

The macroscopic properties of chemical substances result from the structure and interactions between the atoms and molecules that make up the substance in question. These observable properties can be predicted from known characteristics of the chemical structure and interactions at the atomic level. Macroscopic properties can also be used to predict structures and interactions.

The units you will study that further elaborate upon this big idea are: Atomic structure and properties, Molecular and ionic compound structure and properties, Intermolecular forces and properties, Acids and bases, and Application of thermodynamics.

Chemical reactions involve the rearrangement of matter. To properly understand these chemical transformations, one needs to study what occurs both at the macroscopic and atomic level during the process. Some of the things that are studied include quantifying the amount of resulting products, visualizing intermolecular forces, and observing the rate of transformation.

The units you will study that further elaborate upon this big idea are: Chemical reactions, Kinetics, and Equilibrium.

Energy plays two essential roles in chemical systems. The first role involves describing the distribution and redistribution of energy among the various components of a system during heat exchange, chemical reactions, and phase transitions. The second role involves identifying the enthalpic and entropic forces that cause chemical processes to occur. These forces affect chemical equilibria and how the equilibrium position shifts in response to changes in experimental conditions.

The units you will study that further elaborate upon this big idea are: Kinetics, Thermodynamics, and Applications of thermodynamics.

Now that you have a better understanding of the science practices and ideas that form the basis of all AP Chemistry units, let’s take a look at each unit and the topics covered.

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Illustration of Bromine being heated
Illustration of two beakers showing the rate law of elementary reaction
Table of elements showing Dipole moment trend

AP Chemistry Units and Topics

The College Board’s AP Chemistry course and exam description (CED) indicates that the course material is divided into nine units. Each unit will focus on one or more of the four big ideas. These units are further broken down into several topics through which you will learn and master the prescribed science practices. In this section, we’ll look at each of these units, their weighting in the final AP Chemistry exam, and their related topics.

Here are the weightings of each unit on the AP Chemistry exam:

Units Unit Name Exam Weight
Unit 1 Atomic Structure and Properties 7–9%
Unit 2 Molecular and Ionic Compound Structure and Properties 7–9%
Unit 3 Intermolecular Forces and Properties 18–22%
Unit 4 Chemical Reactions 7–9%
Unit 5 Kinetics 7–9%
Unit 6 Thermodynamics 7–9%
Unit 7 Equilibrium 7–9%
Unit 8 Acids and Bases 11–15%
Unit 9 Applications of Thermodynamics 7–9%

AP Chemistry Labs

Labs are an integral part of AP Chemistry, and they will help you better understand and apply the concepts that you are learning in class. At least 25% of your class time will be devoted to labs, and there are at least 16 different lab experiments to complete. These labs give you the skills to adopt an inquiry-based approach to studying chemistry, which will be highly useful when you get to college.

Listed below are some of the topics you will explore through the lab experiments you will perform in your AP Chemistry course:

  1. Redox Titration
  2. Solubility
  3. Acid-base Titration
  4. Buffers
  5. Stoichiometry
  6. Spectroscopy

To find out more about the lab experiments, what they will help you learn, and how they play a role in your final AP Chemistry exam, check out our article on AP Chemistry Labs.

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Frequently Asked Questions

This is largely subjective as it depends on your aptitude for chemistry, your interest in the various units in the course, and the study materials and resources you use. However, taking into account the results of the 2021 exams, it was found that most students struggled with Unit 1, Unit 7, and Unit 8.

Based on the weighting of each unit in the exam, the most important units are Unit 8 – Acids and Bases and Unit 3 – Intermolecular Forces and Properties.

Read more about AP Chemistry

Do you want to know the best strategies and the finest resources to get the highest score in AP Chemistry? Check out our step-by-step AP Chemistry study guide to score a 5.

If you’re wondering if AP Chemistry is right for you, here is the ultimate article on AP Chemistry that clarifies everything about the exam, prerequisites, and more!

Looking for the AP Chemistry Exam format information? Find our article that clearly explains and breaks down the AP Chem Exam format, types of questions, sections, and more!

All you need to know about the AP Chemistry exam scoring system and score distribution—together with the AP Chemistry exam score calculator, to see where you stand.
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