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MCAT Chemistry

Table of Contents

Atomic Structure

See Atomic Structure

The atom is the basic unit of matter that consists of a dense nucleus that contains positively charged protons and neutral charge neutrons, and an area surrounding the nucleus where negatively charged electrons can be found, called the electron cloud. These particles within an atom can further be broken down into parts, which is entering the realm of quantum mechanics and will not be on the MCAT. A description of all the parts of an atom, atomic emission and absorption spectra, quantum numbers, and electron configuration is covered in this section.

Periodic Table Trends

See Periodic Table Trends

The periodic table places the chemical elements in order of increasing atomic number, from left to right, and is also arranged according to electron configurations and chemical properties. Rows are called periods, and columns are known as groups. There are trends that also follow the layout of the table naturally according to the properties of different groups of elements. For example, the atomic radii of the elements increase as you move down a group and decrease as you move from left to right across a period. This section will cover periodic table trends, specifically atomic radii, ionization energy, and electron affinity and negativity.


See Bonding

Bonding is the interactions between different atoms and molecules and allows atoms to rearrange themselves into more complex molecules. There are two major types of bonding, ionic and covalent however there are many sub-divisions of these bonds that govern how interactions occur.

In addition to understanding basic bonding for the MCAT, you will also need to understand complex concepts such as hybridization and molecular geometry. In effect this section is extremely similar to general chemistry and contains many bridges to topics already discussed. This is a good review of the chemistry concepts that relate to the organic chemistry section of the MCAT.

Chemical Reactions

See Chemical Reactions

Chemical Reactions are processes in which starting materials interact to form new compounds, known as products. The bases of chemical reactions are the various bonds between atoms and intermolecular forces. Bonds consist of electrons from two atoms being shared in varying numbers of pairs and equality, and intermolecular forces are forces that act on molecules to bring them closer together, but are not considered true bonds because electrons are not involved, and tend to be weaker than a true bond. In this section, ionic bonds, covalent bonds, lewis dot structures, VSEPR theory, orbitals and bonding, and the various intermolecular forces will be discussed in detail.


See Stoichiometry

Stoichiometry is a subset of chemistry developed to compute the relative amounts of reactants and products in a chemical reaction. Stoichiometry relies on a number of mathematical equations to determine information such as molarity and percent composition. Stoichiometry and the various types of reactions are covered in this section.

Kinetics & Equilibrium

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Kinetics & Equilibrium are theories that determine the rate of chemical reactions and the balance of a reaction favored towards either the products or the reactants, respectively. The theories, reaction rates, factors affecting reaction rates, and Le Chatelier's Principle are covered in this section.


See Thermochemistry

Thermochemistry is the branch of chemistry related to heat and the transfer of energy. The addition of heat energy to a reaction tends to speed up most reactions, make reactions more efficient, and can even possibly cause unwanted reactions or degradation of the product if too much heat energy is introduced. Reaction systems, states, heat, enthalpy, entropy, and Gibb’s Free Energy are covered in this section.

Phases of Matter

See Phases of Matter

The Phases of Matter are the various physical states that matter can be found in at specific ranges conditions. The phases include solids, liquids, gases, and plasma, although, for our purposes, plasma need not be covered. Most people understand the transition matter can make from solid to liquid, and liquid to gas, and back again, but matter can also completely skip a step and move from solid to gas (sublimation) or gas to solid (deposition). In this section, a description of the phases of matter, the transitions between phases, and notable calculations specific to each phase are discussed in detail.


See Solutions

Solutions are homogeneous mixtures of two or more substances in a single phase. Solutions are often used in chemistry to provide a way to react chemicals that, when in the solid phase, would not normally react with each other. Solutions also provide a way to easily add heat and catalysts to reactions, among many other benefits. In this section, solubility, electrolytes, concentration equations, and the Law of Mass Action are covered.

Acids and Bases

See Acids and Bases

Acids and Bases can be defined in numerous ways, but the MCAT will test you on all of them, so the Arrhanius System, Bronsted-Lowry System, and the Lewis System of defining acids and bases will be covered in this section. Auto-ionization of water, pH and pOH, the difference between strong and weak acids and bases, conjugate base pairs, and titrations will also be covered in this section.


See Electrochemistry

Electrochemistry is the branch of chemistry involved with chemical reactions in solution that are interfaced between an electrode and electrolyte, allowing electron transfer to occur. Reduction-Oxidation, or Redox reactions are the result of electrochemical reactions. Redox reactions, oxidation numbers, the split reaction technique, chemical batteries, and the thermodynamics of redox reactions are discussed in this section.

Reference Guide

See Reference Guide

MCAT Chemistry

Chemistry Topics