how much chemistry is on the mcat

How Much Chemistry Is On The MCAT? The Full Guide 2023

How much chemistry is on the MCAT? Here's all you need to know about MCAT general chemistry questions, as well as tips for improving your score.

June 17, 2022

The MCAT is the most essential exam you’ll take before applying to medical school, and doing well on it may considerably boost your chances of being accepted. The MCAT is undeniably the most demanding and longest exam you’ll take before medical school, in addition to being the most significant exam, you’ll take.

On the MCAT, many premed students are struggling with general chemistry problems. MCAT chemistry questions can be frustrating, with seemingly hard math problems and equations that you can’t seem to recall.

So, how much chemistry is on the MCAT? 

Chemistry, in addition to accounting for the bulk of the MCAT Chemistry and Physics part, also accounts for 35% of the MCAT Biology section, making it the second-most tested topic on the MCAT behind biology.

As a result, in order to do well on the MCAT, you must have a firm grasp of the concepts and categories of chemical knowledge assessed.

We’ll go over all of the chemistry concepts evaluated on the MCAT, as well as tactics and study advice to guarantee you ace all of the chemistry the AAMC has to offer.

How much chemistry is on the MCAT?

The Chemical and Physical Foundations of Biological Systems (CPBS) portion, sometimes known as the Chemistry and Physics section, is, of course, dominated by chemistry. In fact, chemistry makes up more than 70% of this section:

how much chemistry is on the mcat

This part of the MCAT evaluates your ability to answer problems based on your understanding of fundamental concepts, scientific investigation, and reasoning abilities. Because the CPBS part is the first you’ll see on the MCAT, it’s critical that you breeze through it. CPBS, like every other science-based portion of the MCAT (excluding CARS), consists of 59 questions that are divided between discrete or one-time questions and passage-based questions. You will have 95 minutes to finish this subject, same as the other scientific sections of the MCAT.

Chemistry is also important in the section on Biological and Biochemical Foundations of Living Systems (BBLS):

how much chemistry is on the mcat

With chemistry accounting for about a third of the CPBS section and a third of the BBLS section, it’s difficult to overestimate the relevance of these many modalities of chemistry when it comes to learning. Because the CPBS component of this tutorial is our major emphasis, biochemistry will only be mentioned on occasion. Regardless, with general and organic chemistry accounting for 10% of BBLS questions, most of what we explain here will apply to the MCAT chemistry questions in both sections.

An ultimate guide for determining which chemistry concepts you should review

The MCAT’s wide range of chemistry knowledge might make planning a study schedule seem intimidating. Fortunately, there are certain fundamental best practices that can help you successfully organize your energy and time.

Taking a full-length MCAT diagnostic test is always the first step. There’s no way to tell for sure what your baseline knowledge is until you’ve imitated the exam process and forced yourself to think under pressure. This involves doing your diagnosis in a quiet room with only a copy of the periodic table and some blank paper.

While various prep businesses and question banks offer a variety of tests, the greatest option for your initial diagnostic is one that comes directly from the horse’s mouth.

As you look over your findings, go through each erroneous answer slowly and make a note of which of the aforementioned categories it belongs to. As you do this, patterns should develop, as erroneous responses are frequently found within a topic such as:

  • Problem-solving
  • Interpretation
  • Data analysis
  • Chemical formulae
  • Fundamental concepts in chemistry

You may then plan out when you’ll start preparing for the MCAT in earnest. We recommend starting no more than 6 months ahead of your preferred examination date, as doing so will likely result in you losing everything you learned earlier in the process.

After you’ve committed to an MCAT study plan, you may start fine-tuning your sessions to include MCAT chemistry questions, MCAT physics equations, and MCAT biology questions in varying quantities based on your needs.

Question banks like UWorld can also assist with this since they allow you to focus on certain subtopics and evaluate explanations and rationales after erroneous replies. Although we don’t advocate taking practice examinations from organizations like UWorld as an initial diagnostic test, they can be useful if you need to build or restore subject-specific muscles in biochemistry, organic chemistry, and other subjects.

Nonetheless, around the halfway point in your preparation, we recommend taking another of the AAMC’s mock MCAT examinations to offer an updated diagnostic baseline. As usual, the more input you get, the better, so talk to an MCAT teacher or prep service to see if you may benefit from some additional professional advice and comments.

It’s better to seek this assistance before the halfway point in your schedule, but if things are very challenging at that point, you’ll still have enough time to benefit from further assistance before the big day.

As you near the end of your MCAT preparation, you’ll want to shorten your review sessions and focus on more practice questions, elongating your sessions to begin to approximate the arduous time of the MCAT.

With the various tasks you’ll have in regard to your undergraduate studies, this might be challenging, so aim to reduce additional stress and scheduling complexity as much as possible during the last month or two of your plan. To earn a decent MCAT score, you will need to temporarily sacrifice or at least limit your social interactions in order to optimize your studying.

MCAT Chemistry questions: How to prepare

There are no trick questions

Throughout the test, the more nervous section of your mind will gleefully remind you that no question is simple and that if an answer appears simple or clear, you’re either thinking about it incorrectly or don’t understand it. Slow down if this tiny goblin appears while you’re studying or taking an exam.

The most prevalent cause of incorrect answers is rushing, even if you’re a seasoned scientific student who has carefully prepared for months before exam day. Most seemingly difficult—even unsolvable—questions are actually rather simple.

The MCAT has some tricky questions, but the test creators aren’t trying to fool you with phrasing. Reread a question if your initial impulse is to think of it as a 400-level midterm brain-melter, and believe that the exam isn’t attempting to trick you into answering poorly.

The study material for application rather than memory

When studying for the MCAT, time is incredibly precious. As a result, rather than memorizing knowledge, you should study it for application to practice passages and unique circumstances that the MCAT may throw at you.

The MCAT will almost never require you to recite a random chemical fact. Instead, the MCAT will give you a truncated scientific article in the form of a passage, ask you to critically assess it, and ask you questions that require you to connect your outside knowledge with the passage’s expertise.

So, what does studying content for application rather than memorizing imply? When studying each MCAT general chemistry subject, think of three different ways the MCAT may test you on that information. Consider the case of nucleophilic acyl substitution.

Many students become nervous when they hear the phrase nucleophilic acyl substitution since the reaction might take many distinct forms. In acidic vs basic circumstances, for example, the reaction appears slightly different, and the nucleophile and the leaving group can take a number of forms. The general principles behind the diverse responses, however, are the same:

1) A carbonyl carbon is attacked by a nucleophile.

2) Electrons are transferred to an oxygen atom, which now has a negative charge.

3) The electrons then return to the oxygen atom to re-establish the double bond.

how much chemistry is on the mcat

What are three ways the MCAT may put you to the test when it comes to nucleophilic acyl substitution?

1) Saponification of triglycerides

2) The process of transesterification

3) Cleavage of anhydride

The first example is particularly significant since it links several MCAT concepts. The breakdown of triglycerides into the glycerol backbone and fatty acids is known as triglyceride saponification, and it follows the same principles as nucleophilic acyl substitution. The R group is the glycerol backbone this time, the nucleophile is a strong base (like OH-), and the leaving group is a fatty acid!

Check the passages first if you don’t understand something

On first reading, passage-based questions are frequently unreliable. That example, you may be asked to define or supply a formula for something wholly unrelated to the core chemical concepts and knowledge base provided in the article’s categories.

If that’s the case, don’t panic if you don’t know the chemical formula for Brochantite—in nearly all cases, that information will have been given, though briefly, in the chapter to which the question is linked.

If a question linked to one looks completely out of the blue, or if it appears to be asking for information outside the purview of beginning chemistry/etc., it’s practically a certainty that your answer is right there in plain sight only a few inches away. Reread the text carefully and concentrate on finding the solution in the information supplied.

Except when the question includes chemistry, the MCAT isn’t about memory

The truth of the MCAT’s CPBS portion is that you’ll need to memorize quite a few facts, but they’re all interconnected in some manner. Numerical and nomenclatural prefixes and suffixes, for example, are critical—being able to describe the difference between chlorite and chloride compounds in clear English will save time.

When studying for the MCAT, memorization isn’t the be-all and end-all [RN1], but it is an important aspect of constructing the toolbox needed to correctly interpret the language employed in a chemical question.

Even though you’ll have access to a periodic table during the exam, learning as much of it as possible will be beneficial. The pop-up table on your testing screen should be used to corroborate your intuition or hypothesis rather than as a cheat sheet.

Even if you have trouble memorizing, this is significant since the time spent switching back and forth between the table and the exam may mount up quickly if you do so frequently.

Furthermore, the table supplied, like other periodic tables, does not provide full names of elements or vertical/horizontal trends, so you’ll have to figure out a lot of information on your own.

There’s a lot more chemistry and physics to remember for the CPBS part, but starting with these fundamentals, as well as common strong acids, strong bases, and polyatomic ions, will help you structure the more complex laws and equations you’ll need to remember come exam day.

Practice converting units

Having to physically compute unit conversions is one of the most time-consuming aspects of the CPBS section. Regular, if not daily, practice in multiplication and dividing by negative exponents, as well as studying how to convert the results of these calculations into many other units, should be included in your studies. This will help you save time and get accurate results quickly.

Simple questions should come first, then go back for passages

Discrete questions, or short one-off questions with four possible responses, should be rather straightforward by the time your exam day arrives. Because of the MCAT’s extensive knowledge base, these questions will frequently only need memorization of a fact or a basic computation.

Getting these simple-format questions out of the way before moving on to the more involved multiple-question passages will not only help you maximize the amount of time you have to read and analyze the passage’s text, but it will also likely boost your confidence for the more uncertain, even alien terrain that comes with it.

Half of your confidence boost will depend on having your hypotheses verified at least most of the time—that is, whenever you approach a discrete question, take a moment to formulate a broad hypothesis about the proper answer after carefully reading the question. This will allow you to eliminate answers that are clearly erroneous more quickly, giving you more time to choose amongst the likely correct responses.

A complete list of MCAT chemistry concepts

The MCAT is organized by the AAMC on ten Foundational Concepts that are spread over the four sections of the exam. Two of these fundamental principles are the focus of the Chemical and Physical Foundations of Biological Systems section.

It’s vital to notice right away that these core principles are articulated in somewhat extensive terms, so you’ll need to be able to both grasp and paraphrase them as provided by the AAMC.

The MCAT typically covers the range of subjects and concepts covered is extensive, but the depth to which any question will go is always restricted. The main majority of chemistry information examined on the MCAT will come from introductory and general chemistry, as well as first-year organic and biochemistry, as seen in the tables above.

Advanced molecular spectroscopy is not required, but you must be highly familiar with the fundamentals of mass spectroscopy. Let’s dive—or rather, wade—into the shallow but large pool of Foundational Concepts 4 and 5 for a complete overview of the MCAT chemistry subjects you’ll need to know.

Foundational Concept 4 

Complex organisms, such as the human body, employ physical principles to move materials, perceive and interpret ambient data and internal signals, and adapt to changes. These intra-organism processes may be described and quantified using equations and behavioral models because they function according to physical rules.

“The concepts of electromagnetic radiation, and their interactions with matter, can be utilized to create structural information about molecules or to take pictures of the human body,” according to the AAMC definition.

As a result, atomic structures may be used to forecast or simulate the physical and chemical characteristics of atoms, which could include calculating processes like ionization based on electromagnetic radiation in this case.

This may sound like a lot, but comprehending the nature of the CPBS section requires a grasp of the fundamental connections between physics and chemistry. There will be a few discrete questions that require you to simply calculate things like molar mass, but passage-based issues will require you to comprehend the synergistic nature of physical and chemical rules in order to choose your strategy to respond.

The diagnosis and treatment of frequently complex/systemic disease pathologies are shaped by this foundational understanding. As a result, difficulties relating to the physiological activities of the neurological, cardiovascular, and respiratory systems in human health will frequently appear in this area.

Foundational Concept 5 

The concept of FC5 is how the micro influences the macro. The scientific knowledge of “molecular dynamics of biological systems” is based on chemical concepts at the atomic and subatomic levels.

Furthermore, understanding the function of chemical processes in the formation of diverse frameworks, such as thermodynamics, intermolecular interactions, molecular dynamics and reactivity, and, of course, molecular structure, will be required.

The MCAT will require students to apply these key ideas to questions about molecular and cellular activities in human health and illness。

This fundamental concept’s categories make up the core pillar of chemistry knowledge assessed on the MCAT, accounting for the majority of questions in the CPBS segment.

Make a note of their appearance in any study resources you have so far when examining these areas. Although much of it is general chemistry, so you should be familiar with it, some of the biochemistry-focused subcategories may require more specialist study resources to compensate for any gaps in your earlier training.


How much organic chemistry is on the MCAT?

You probably spent a semester or two studying organic chemistry, yet the MCAT will only ask you roughly 6 to 12 questions on it out of 230 total questions. In other words, organic chemistry is expected to account for only 3 to 5% of your overall test.

What types of MCAT chemistry questions?

Broad chemistry, biochemistry, and organic chemistry are the three general categories of chemistry knowledge assessed on the MCAT. There are many subtopics within those broad categories, but the great majority of chemistry questions will draw from general and biochemistry, so making sure you understand the fundamentals of these subjects will be crucial as you study.

How can I quicken my passage-based questions?

Surprisingly, parts of the CARS technique can be really useful in this respect, especially with chemical sections. For any passage-based inquiry, active reading is critical—you should be able to approach a text with queries like “what is the theme of this passage?” in mind, as well as summarise longer phrases for better understanding.

Reading difficult material during exam preparation will also enhance and speed up your analytical abilities, even on scientific parts. In general, the better you are at reading and thinking while reading, the better you will do on exam day with all passage-based questions.

Are difficulty practice questions and tests better?

Both yes and no. There’s a place for really difficult practice questions and topic exams, but for diagnostic reasons, it’s always better to choose to practice exams that closely resemble the actual MCAT.

You want an accurate assessment of your ability at the start and halfway through the test, therefore attempting material that is meant to be more difficult than the actual exam will certainly lead to disappointment.

Include deliberately tough computations and passages in your study sessions, but do so in moderation. After all, you’re taking the MCAT, not the USMLE Step-2.

How do I study for the organic chemistry part?

Simply said, you’ll require additional time. The good news is that because the MCAT is “a mile wide and an inch deep,” you may concentrate on building a broad base of basic or fundamental knowledge rather than becoming overly specific about any one component of organic chemistry.

If you have the time, take a summer course in whatever prerequisites you haven’t finished, but if you don’t, you may always look for the textbooks from these classes and go through them thoroughly.

In this instance, however, hiring an MCAT instructor or prep service will be the most effective and time-saving alternative, since they will be able to create a study schedule that is tailored to your individual needs.


So, how much chemistry is on the MCAT? Chemistry accounts for almost 70% of CPBS questions, with general and organic chemistry contributing to 10% of BBLS questions.

This article included all of the necessary information as well as practice strategies for MCAT chemistry questions.

Remember that you’ll need to devote a significant amount of time to studying for the MCAT and that we’ll be here to help you along the way! We’ve got your back, and you’ve got this!

Don’t forget to take our free MCAT practice test at Medtutor to get familiarized with the format as well as the questions of the actual exam to strengthen your knowledge and skills, as a result, enhancing your chance to pass the MCAT exam with a high score on your first attempt. Good luck to you!