For students planning to start their career in the medical field, the MCAT exam is an important step.
This exam is administered by the Association of American Medical Colleges (AAMC), and it can make or break your chance of getting into your dream medical school.
The MCAT is a difficult test for anyone to take.
But, because this test primarily focuses on life sciences and physical sciences, if you do not have a solid foundation in general chemistry, you will not likely do well on the MCAT.
Summary of the Key Findings
- General chemistry is a major part of the Chemical and Physical Foundations of Biological Systems section of the MCAT.
- To do well on the exam, you need a good foundation in chemical knowledge and concepts.
- You need to be able to solve problems, apply concepts, and use reasoning skills.
General Chemistry: Critical Reasoning Foundations
MCAT general chemistry (along with physics, organic chemistry, and biochemistry) is a key component of the Chemical and Physical Foundations of Biological Systems section.
In fact, it is the single largest tested component of this MCAT section - a full 30% of questions will come from general chemistry [1].
It is not enough for test-takers to simply know the principles of general chemistry; they must be able to think critically.
Interpreting data and using reasoning skills will get you a far better MCAT score than just memorizing general chemistry facts and formulae.
"I am among those who think that science has great beauty." - Marie Curie, chemist
That being said, there is no getting around the fact that you need a strong, present grounding in general chemistry to score well on the MCAT.
So let's explore what general chemistry material you need to look at during your MCAT review.
General Chemistry Subjects On The MCAT
Here is the range of MCAT chemistry subjects you can expect.
These topics are ripe for study on your MCAT general chemistry review, as they are the areas of general chemistry that will benefit you the most on the MCAT.
1. The Periodic Table and Atomic Structure
Atomic Structures:
- Protons, neutrons, and electrons of the Bohr atom
- Conventional structural notation
- Orbital structure and shapes
- Electrons per orbital and quantum numbers
- Nuclear charge
- Ground and excited states
- Emission and absorption
Periodic Table:
- Classification of elements into groups by atomic structure
- Physical and chemical properties of groupings, including alkali metals, halogens, transition metals, alkaline earth metals, oxygen group, and noble gasses.
- Understand metals vs. nonmetals
- Representative elements of groups and rows
- Definition of ionization energies with the prediction from electronic structure
- Definition of electron affinity and the variation throughout the periodic table
- Definition of electronegativity comparative values across the table
- Electron shells and the sizes of atoms
2. Bonds and Bonding
Ionic Bonds
- Definition
- Lattice energies
- Electrostatic energy and force
Covalent Bonds
- Definition
- Pi and sigma bonds, valence shell electron pair repulsion theory, and hybrid orbitals
- Lewis electron-dot formulae with Lewis acids and bases, formal charge, and resonance structure
- The partial ionic character with dipole moments and charge distribution
3. Phases of Matter
Gas Phase
- Absolute zero and the Kelvin scale
- Pressure and the mercury barometer
- Partial pressures and mole fraction
- Molar volume at standard temperature and pressure
- Ideal gas definition and law - Boyle's, Charles', and Avagadro's laws
- Real-gas behavior and the Van der Waals' equation
- Dalton's law
- Kinetic theory of gases
Liquid Phase
- Hydrogen bonding
- Dipole and intermolecular interactions
- Van der Waals' forces
Phase Equilibria
- Phase changes and change diagrams
- Freezing point, melting point, boiling point, and condensation point
- Freezing point depression, boiling point elevation, and vapor pressure lowering
- Osmotic pressure
- Molality
- Colloids
- Henry's Law
4. Stoichiometry
- Molecular weight and composition by percent mass
- Empirical versus molecular formula
- Avagadro's number, the mole, and density
- Oxidation number, reducing and oxidizing agents, titration, disproportionation
- Chemical equations - writing, balancing, limiting reagents, and theoretical yields
- Metric units used in chemistry and dimensional analysis
5. Thermochemistry And Thermodynamics
Thermochemistry
- Definition
- Thermodynamic system and states
- Conservation of energy
- Exothermic and endothermic reactions
- Standard heats of reaction and formation; bond dissociation
- Enthalpy
- Hess' law
- Calorimetry, heat capacity, specific heat capacity
- Entropy and relative entropy for gas, liquid, and crystal states
- Free energy, spontaneous reaction, and ΔG°
Thermodynamics
- Zeroth, first, and second laws
- Equivalence of mechanical, chemical, electrical, and thermal energy units
- Temperature scales and conversion
- Types of heat transfer
- Heats of fusion and vaporization
- PV diagram
6. Kinetics and Equilibrium
- Reaction rates and rate law
- Dependence of reaction rate on the concentration of reactants, reaction order, and rate constant
- Rate-limiting step
- Dependence of reaction rate on temperature including activation energies, transition state, activated complex, ΔH, Arrhenius equation
- Kinetic and thermodynamic control of reactions
- Catalysts, enzymes, and other molecules
- Equilibrium in reversible chemical reactions, equilibrium constant, LeChatelier's principle, and Law of Mass Action
- Relationship between standard free energy change and the equilibrium constant
7. Solutions and Acid-Base
Ions
- Anions, cations
- Formulae and names for common ions
- The hydronium ion
Solubility
- Molarity
- Solubility product constant
- Equilibrium expression
- Common-ion effect
- Complex ion formation, solubility, and pH
Acid / Base Equilibria
- Definition of pH; pH of pure water
- Bronsted definition of acid, base
- Ionization of water, Kw
- Strong, weak, and conjugate acids and bases
- Dissociation of weak acids and bases with or without added salt
- pH calculation and hydrolysis of salts of weak acids and bases
- Ka, Kb, pKa, pKb
Buffers
- Definition and common buffer systems
- Titration and titration curves - interpretation, redox reactions
- Indicators and neutralization
8. Electrochemistry and Reduction-Oxidation Reactions
Electrolytic Cells
- Electrolysis and electrolytes
- Anodes and cathodes
- Faraday's law
- Electron flow - oxidation and reduction at the electrodes
Galvanic and Voltaic Cells
- Half reactions
- Reduction potential and cell potential
- Electron flow
Study Tips and Strategies for MCAT General Chemistry
Many students have trouble with MCAT chemistry (and organic chemistry, for that matter).
- Learn the chemical properties, structures, three-letter code, and one-letter code of all the amino acids. Although this examination of amino acids blurs the line into organic chemistry and biochemistry, these molecules are as foundational as anything in MCAT general chemistry.
- Review every practice MCAT you take and study any practice questions that you miss. Learn the underlying information (not just the answer), so you don’t repeat the same mistake. Use every incorrect answer choice as a launch point to improve your weak areas.
- Practice by hand. Writing formulae and problems out long-hand is a different way to cement the concepts and knowledge in your mind during your MCAT prep.
- Look at the answers before you do the problem. MCAT general chemistry problems can take a long time to work out. Eliminate answers you are sure are incorrect, and you may come to a solution without actually having to finish the problem.
MCAT General Chemistry Review
Many premed students struggle with the principles of chemistry. As alluded to before, it is important to understand general chemistry concepts to do well on the MCAT. However, that is not enough.
Although 35% of questions in this section will test your general chemistry knowledge, a full 45% are based on your scientific reasoning and problem-solving. [2]
In other words, the MCAT requires you to apply your knowledge and foundational concepts of general chemistry to evaluate scientific predictions and explanations.
A good score on the MCAT general chemistry section does not occur spontaneously. But by honing your skills with learning materials, videos, and courses, you can be confident that you will do well on the MCAT test day.
References:
- https://students-residents.aamc.org/whats-mcat-2015-exam/chemical-and-physical-foundations-biological-systems-section-overview
- https://students-residents.aamc.org/prepare-mcat-exam/whats-mcat-exam
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