Testing out of college courses is an excellent way to start your college career right and get the most of your time on campus. By applying the knowledge you already have from your more advanced high school chemistry classes, you can skip the boredom that is entry level chemistry in college and progress to higher level courses. Or, if chemistry isn’t your thing, you can sit through one less science course and fill your schedule with the courses that interest you. The CLEP Chemistry exam allows you to test out of Chemistry 101 (or similar). Read on to learn exactly what is on the CLEP Chemistry exam.
CLEP Chemistry: The Basics
The CLEP Chemistry exam consists of 75 questions (give or take a few) about concepts generally covered in a basic college chemistry course. You will have an hour and a half to answer these questions. It’s important to note that not all questions will be scored; there are pretest questions. However, you won’t know which ones are scored and which ones are not. CLEP Chemistry questions are written at the recall, application, and interpretation levels. This means that for some questions, you will only be required to regurgitate facts and definitions (recall). Application questions will take the knowledge a step further and prompt you to use your knowledge to solve problems present in the questions. Interpretation questions will present you with data, require you to integrate the information, and develop conclusions; you will also have to recognize assumptions that are not explicitly stated in the question stem.
Structure of Matter: 20%
In order to ace the Structure of Matter questions, you will need to be comfortable with atomic theory and structure. This includes evidence supporting atomic theory, how to determine atomic mass by physical and chemical means, and recall the atomic and mass numbers. You will also need to be knowledgeable about isotopes and mass spectroscopy. Electron energy levels will make an appearance, so be familiar with atomic spectra and orbitals as well as quantum numbers. Atomic radii, oxidation states, electron affinities, and ionization energies will be topics of questions that test your knowledge of the relationships between elements on the periodic table.
Another main topic in the Structure of Matter category is chemical bonding. This might include information on the various types of binding forces (think hydrogen, covalent, metallic, ionic, dispersion, or macromolecular bonding). Be prepared to discuss the relationships of binding forces to properties of atoms and atomic structures. Bond polarity and electronegativity will make an appearance, as well. Make sure to have a firm grasp on the geometry of ions, molecules, and coordination complexes. Coordination complex questions go deeper to cover how properties affect structure, the dipole moments of molecules, and structural isomerism. Be familiar with the various molecular models including, but not limited to, sigma/pi bonds, resonance, orbital hybridization and the theory of valence bonds.
Nuclear chemistry is the third and final topic that makes up the Structure of Matter category. Nuclear equations, molecular half-lives, and nuclear radioactivity will test your nuclear chemistry knowledge. Additionally, you will need to be prepared to answer questions about applied chemistry.
States of Matter: 19%
Gases, liquids, solids, and solutions are the main topics in the States of Matter category of questions. You’ll need to be familiar with the kinetic-molecular theory of gases and be able to use this theory to interpret the ideal gas laws. Avogadro’s number and the mole concept will be the topic of questions, to be sure. You should be familiar with the Boltzmann distribution and how temperature affects molecular kinetic energy. In addition to understanding ideal gas laws, you must be comfortable discussing the deviations from them.
Liquids and solids will be discussed from the viewpoint of molecular kinetics. One-component system phase diagrams are sure to be covered on the CLEP Chemistry. State changes and critical phenomena are common questions on the exam. Be familiar with buffers, the common ion effect, and complex ion constants, as well as crystal structure.
You will see questions testing your knowledge of solutions. These questions might cover the various solution types and factors that affect solubility. Be able to express concentration in a variety of ways. An understanding of Raoult’s law and the other colligative properties is crucial to successfully passing the CLEP Chemistry exam. Additionally, you should be familiar with how attractions between ions affect solubility and the colligative properties.
Reaction Types: 12%
Be prepared to answer questions about how covalent bonds are formed and cleaved. These topics might include amphoterism and the Lewis, Arrhenius, and Brønsted-Lowry concepts. You will certainly see questions about acid-base and coordination complex reactions. Be familiar with precipitation reactions. Additionally, oxidation-reduction reactions are sure to make an appearance. You’ll need to know oxidation numbers of elements and how electrons affect oxidation-reduction reactions. Further reaction-type questions discuss electrochemistry. These questions will cover half-cell potentials and electrocytic cells. Additionally, you should be able to predict redox reaction directions and how concentration changes effect reactions.
Equations and Stoichiometry: 10%
Roughly 7-8 questions on the test will deal with chemical equations and stoichiometry. These questions could include net-ionic equations and the species of ions and molecules. When studying stoichiometry, focus on the mole concept while reviewing the relationship between mass and volume. Practice balancing chemical equations.
Fewer (about 5) questions will cover topics related to the various types of equilibrium and the equilibrium constants. Additionally, you should know and be able to apply LeChâtelier’s principle. Be prepared to discuss how equilibrium is quantified. Use partial pressures and molar concentrations to describe the equilibrium constants of gaseous reactions. Be comfortable using equilibrium constants in solution reactions, such as pK and pH. Use solubility-product constants in slightly soluble compound dissolution and precipitation reactions. Buffers, common ion effect, and complex ion constants should be reviewed as well.
While only 2-3 questions will cover kinetics, it should still be reviewed. Understand the rate and order of reaction as well as the rate constant. Describe how rates are affected by temperature change. You should be familiar with how temperature change effects rates of reactions. Be sure to study how rate-determining steps affect mechanisms in addition to the concepts of activation energy and catalysts.
Another small category, thermodynamics accounts for just 2-3 questions. Familiarize yourself with the First law of thermodynamics – heats of reaction, formation, fusion, and vaporization, heat capacity, Hess’s law, and enthalpy. The second law of thermodynamics should be reviewed as well. You might see questions about the free energy of reaction and formation and how entropy and enthalpy changes affect free energy. Describe how free energy changes relate to electrode potentials and equilibrium constants.
Descriptive Chemistry: 14%
Descriptive chemistry questions make up a much larger part of the exam. You’ll need to be familiar with the nomenclature used to communicate chemical theories and concepts. These questions will test your ability to apply principles to practice and your comprehension of important principles and concepts. Specifically, you’ll need an understanding of the products of chemical reactions and chemical reactivity, how elements in the periodic table relate to each other, and organic chemistry.
Experimental Chemistry: 9%
Familiarize yourself with the tools, calculations, and processes used to perform common chemistry experiments. Additionally, you should be prepared to discuss the observations and interpretations of these results. Further, review how these common experiments are applied to chemical systems.
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