AP Chemistry

How Is the AP Chemistry Exam Structured?

Like other AP tests, the AP Chemistry exam has two sections: a multiple-choice section and a free-response section. On both sections, you will have access to a periodic table of the elements as well as a chart listing any formulas and constants you might need for your calculations.

The Multiple-Choice Section

Here is a brief overview of the multiple-choice section on AP Chemistry:

  • Number of Questions: 60 questions with four answer choices each
  • Time: One hour and 30 minutes
  • Scoring: Worth 50% of your total AP Chemistry score
  • Calculator Use: Prohibited

Be aware that some of these questions will exist as a part of question groups (which consist of a few questions that ask about one set of data), whereas others will stand on their own.

The Free-Response Section

Next up, here is an overview of the free-response section on AP Chemistry:

  • Number of Questions: Four short-response questions and three long-response questions
  • Time: One hour and 45 minutes
  • Scoring: Worth 50% of your total AP Chemistry score
  • Calculator Use: Allowed

Question Topics

Finally, here are the main topics you’ll be tested on with the AP Chemistry exam:

  • Experimental design
  • Analyzing data and identifying patterns or explaining phenomena
  • Creating or analyzing atomic and molecular views to explain observations
  • Articulating and then translating between representations of data
  • Following logical/analytical pathways to solve a problem

How Is the AP Chemistry Exam Scored?

As mentioned above, the multiple-choice and free-response sections are each worth 50% of your total score. No points are taken off for incorrect answers on either section (i.e., there is no guessing penalty).

To calculate your raw multiple-choice score, add up all of your correct answers. This means you can earn a maximum of 60 points on the multiple-choice section.

While the free-response section is a little more complicated, you should be able to figure out how many points you’ve earned if you have scoring guidelines. Short-response questions are worth 4 points, and long-response questions are worth 10 points, meaning you can earn a maximum of 46 points on this section.

Next, convert these raw scores into numbers out of 50 so that they each make up half your final raw score. Say you got 40 out of 60 multiple-choice questions correct. You would convert this score to the equivalent fraction of 33 out of 50. Then, if you got 30 out of 46 points on the free-response section, you would convert that score to the equivalent fraction of 32 out of 50 points.

Finally, add the two scores out of 50 together to get your final raw score out of 100. You can use the conversion chart below to estimate how your raw score might translate to an AP score (on a scale of 1-5). In this case, your raw score of 65 would be right in the middle of the 4 range.

We can’t be absolutely sure that these raw score ranges will correlate exactly with these AP scores because the curve is slightly different every year. If you find you’re close to the bottom of your goal score range in practice testing, don’t get complacent! You should probably put in a little more studying so you can feel more secure.

Raw Score AP Score Percentage of Students Earning Each Score (2017)
72-100 5 10.1%
58-71 4 16.2%
42-57 3 26.1%
27-41 2 26.2%
0-26 1 21.4%

Source: The College Board

What Do You Need to Know for the AP Chemistry Test?

The AP Chemistry test centers around six major themes, or big ideas, which encompass all the topics covered in the AP Chemistry course. I list them here to give you an overview of what kinds of ideas you should be familiar with before taking the test.

Big Idea 1: Chemical Elements and Matter

The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangement of atoms. These atoms retain their identities in chemical reactions.

In terms of specific topics, here’s what this idea covers:

  • Compounds in atomic molecular theory
  • Using mass data to identify the composition or identity of a chemical substance
  • Units in chemistry: particles vs. moles vs. mass vs. volume
  • Electrons (distribution in atoms and ions, energy levels, Coulomb’s Law, classic shell model vs. quantum mechanical model)
  • Structure of the periodic table
  • Mass spectrometry
  • Spectroscopy/light absorption and chemical composition of a solution
  • The Law of Conservation of Mass
  • Gravimetric analysis and titration

Big Idea 2: Chemical and Physical Properties of Materials

With this big idea, both the chemical and physical properties of materials can be explained by the structure and arrangement of atoms, ions, or molecules and the forces between them.

This idea covers the following topics:

  • Molecular structure and its connection to a substance’s properties
  • Phase changes (solids, liquids, gases)
  • Chromatography
  • Interactions between solutes and solvents
  • London dispersion forces
  • Polarity of atoms and molecules
  • Coulomb’s law and the interactions of ions
  • Chemical bonds and why certain atoms form certain types of bonds
  • Bond polarity
  • Properties of metallic elements
  • Lewis diagrams and VSEPR
  • Properties of ionic solids
  • Properties of metal alloys
  • Metallic bonding and the electron sea model
  • Properties of covalent solids
  • Properties of molecular solids

Big Idea 3: Changes in Matter

Changes in matter involve the rearrangement and/or reorganization of atoms and/or the transfer of electrons.

Specifically, this big idea encompasses the following topics:

  • Writing balanced chemical equations
  • Stoichiometric calculations to predict outcome of reactions
  • Bronsted-Lowry acids and bases
  • Redox reactions
  • Difference between physical change, chemical change, or ambiguous change
  • Galvanic or electrolytic reactions
  • Half-cell reactions/potentials and Faraday’s laws

Big Idea 4: Rates of Chemical Reactions

With this idea, rates of chemical reactions are determined by details of the molecular collisions.

Here are some important topics included in this idea:

  • Factors that impact rates of chemical reactions (temperature, concentration, surface area)
  • Calculating rate of a zeroth-, first-, or second-order reaction
  • How half-life relates to rate constant in a first-order reaction
  • Rate law and molecular collisions
  • Catalysts and their impact on chemical reactions

Big Idea 5: The Laws of Thermodynamics

It’s important to know that the laws of thermodynamics describe the essential role of energy and explain and predict the direction of changes in matter.

These laws encompass the following topics:

  • Thermal energy transfer
  • Relating the magnitudes of energy changes in two interacting systems (direction of energy flow, type of energy)
  • How energy changes relate to heat capacity, enthalpy of fusion, enthalpy of reaction, PV work
  • Calorimetry
  • Enthalpy of reactions and connection to chemical bonds
  • Noncovalent interactions between molecules
  • Whether reactions are thermodynamically favored or not
  • Gibbs free energy calculations
  • Le Chatelier’s principle
  • Equilibrium constants

Big Idea 6: Bonds and Intermolecular Attractions

Any bond or intermolecular attraction that can be formed can be broken. These two processes are in a dynamic competition, sensitive to initial conditions and external perturbations.

This big idea covers the following topics:

  • How changes to chemical reactions affect Q and K
  • Relative rates of forward and reverse reactions
  • Equilibrium constant (K) and how to calculate it
  • Calculating equilibrium conditions of a system
  • Direction of the shift resulting from stresses placed on a system at chemical equilibrium
  • Design a set of conditions that will optimize a certain reaction outcome
  • The distinction between strong and weak acid solutions with similar pH values
  • Interpreting titration data to determine the concentration of the titrant/pKa/pKb
  • Calculating the pH of a solution and its makeup
  • Acid/base reactions
  • Buffer solutions – design, identification, reactions
  • Labile protons and how they affect pH
  • Solubility of salts and Ksp
  • Equilibrium constant in terms of △G° and RT