AP CHEMISTRY exam questions weight

Section I: Multiple Choice | ~60 Questions | 1 hour and 30 minutes | 50% of Exam Score

• Questions are either discrete questions or question sets, in which you are provided with a stimulus or a set of data and a series of related questions.
• A calculator is not permitted on Section I.

Section II: Free-Response | 7 Questions | 1 hour and 45 minutes | 50% of Exam Score

• There are three long- and four short-answer questions
• The questions assess the following skills: experimental design; quantitative/qualitative translation; analysis of authentic lab data and observations to identify patterns or explain phenomena; creating or analyzing atomic and molecular views to explain observations; and following a logical/analytical pathway to solve a problem.
• You will be allowed to use a scientific or graphing calculator on the entire free-response section of the exam. (A four-function calculator is allowed but not recommended.) See this course’s calculator policy and the list of approved graphing calculators.
• Additionally, you will be supplied with a periodic table of the elements and a formula and constants chart to use on both the multiple-choice and free-response sections of the exam.

Structure of Matter (20%)
States of Matter (20%)
Reactions (35–40%)
Descriptive Chemistry (10–15%)
Laboratory (5–10%)

I. Structure of Matter (20%)

Atomic Theory and Atomic Structure

1. Evidence for the atomic theory
2. Atomic masses; determination by chemical and physical means
3. Atomic number and mass number; isotopes
4. Electron energy levels: atomic spectra, quantum numbers, atomic orbitals
5. Periodic relationships including atomic radii, ionization energies, electron affinities, oxidation states

Chemical Bonding

1. Binding forces
   a. Types: ionic, covalent, metallic, hydrogen bonding, van der Waals (including London dispersion forces)
   b. Relationships to states, structure, and properties of matter
   c. Polarity of bonds, electronegativities
2. Molecular models
   a. Lewis structures
   b. Valence bond: hybridization of orbitals, resonance, sigma and pi bonds
   c. VSEPR
3. Geometry of molecules and ions, structural isomerism of simple organic molecules and coordination complexes; dipole moments of molecules; relation of properties to structure

Nuclear chemistry: nuclear equations, half-lives, and radioactivity; chemical applications

II. States of Matter (20%)

Gases

1. Laws of ideal gases
   a. Equation of state for an ideal gas
   b. Partial pressures
2. Kinetic-molecular theory
   a. Interpretation of ideal gas laws on the basis of this theory
   b. Avogadro's hypothesis and the mole concept
   c. Dependence of kinetic energy of molecules on temperatured. Deviations from ideal gas laws

Liquids and Solids

1. Liquids and solids from the kinetic-molecular viewpoint
2. Phase diagrams of one-component systems
3. Changes of state, including critical points and triple points
4. Structure of solids; lattice energies

Solutions

1. Types of solutions and factors affecting solubility
2. Methods of expressing concentration (The use of normalities is not tested.)
3. Raoult's law and colligative properties (nonvolatile solutes); osmosis
4. Non-ideal behavior (qualitative aspects)

III. Reactions (35–40%)

Reaction Types

1. Acid-base reactions; concepts of Arrhenius, Brönsted-Lowry, and Lewis; coordination complexes; amphoterism
2. Precipitation reactions
3. Oxidation-reduction reactions
   a. Oxidation number
   b. The role of the electron in oxidation-reduction
   c. Electrochemistry: electrolytic and galvanic cells; Faraday's laws; standard half-cell potentials; Nernst equation; prediction of the direction of redox reactions

Stoichiometry

1. Ionic and molecular species present in chemical systems: net ionic equations
2. Balancing of equations including those for redox reactions
3. Mass and volume relations with emphasis on the mole concept, including empirical formulas and limiting reactants

Equilibrium

1. Concept of dynamic equilibrium, physical and chemical; Le Chatelier's principle; equilibrium constants

1. Quantitative treatment
   a. Equilibrium constants for gaseous reactions: Kp, Kc
   b. Equilibrium constants for reactions in solution
   (1) Constants for acids and bases; pK; pH
   (2) Solubility product constants and their application to precipitation and the dissolution of slightly soluble compounds
   (3) Common ion effect; buffers; hydrolysis

Kinetics

1. Concept of rate of reaction
2. Use of experimental data and graphical analysis to determine reactant order, rate constants, and reaction rate laws
3. Effect of temperature change on rates
4. Energy of activation; the role of catalysts
5. The relationship between the rate-determining step and a mechanism

Thermodynamics

1. State functions
2. First law: change in enthalpy; heat of formation; heat of reaction; Hess's law; heats of vaporization and fusion; calorimetry
3. Second law: entropy; free energy of formation; free energy of reaction; dependence of change in free energy on enthalpy and entropy changes

1. Relationship of change in free energy to equilibrium constants and electrode potentials

IV. Descriptive Chemistry (10–15%)

A. Chemical reactivity and products of chemical reactions.

B. Relationships in the periodic table: horizontal, vertical, and diagonal with examples from alkali metals, alkaline earth metals, halogens, and the first series of transition elements.

C. Introduction to organic chemistry: hydrocarbons and functional groups (structure, nomenclature, chemical properties). Physical and chemical properties of simple organic compounds should also be included as exemplary material for the study of other areas such as bonding, equilibria involving weak acids, kinetics, colligative properties, and stoichiometric determinations of empirical and molecular formulas.

V. Laboratory (5–10%)

The AP Chemistry Exam includes some questions based on experiences and skills students acquire in the laboratory: making observations of chemical reactions and substances; recording data; calculating and interpreting results based on the quantitative data obtained; and communicating effectively the results of experimental work.

AP Chemistry coursework and the AP Chemistry Exam also include working some specific types of chemistry problems.

AP Chemistry Calculations

When performing chemistry calculations, students will be expected to pay attention to significant figures, precision of measured values, and the use of logarithmic and exponential relationships. Students should be able to determine whether or not a calculation is reasonable.

According to the College Board, the following types of chemical calculations may appear on the AP Chemistry Exam:

1. Percentage composition
2. Empirical and molecular formulas from experimental data
3. Molar masses from gas density, freezing-point, and boiling-point measurements
4. Gas laws, including the ideal gas law, Dalton's law, and Graham's law
5. Stoichiometric relations using the concept of the mole; titration calculations
6. Mole fractions; molar and molal solutions
7. Faraday's law of electrolysis
8. Equilibrium constants and their applications, including their use for simultaneous equilibria
9. Standard electrode potentials and their use; Nernst equation
10. Thermodynamic and thermochemical calculations
11. Kinetics calculations