AP Chemistry Exam Cram Session

Introduction

• Presenter: Jeremy Kug
• Purpose: Cram session covering all nine units of AP Chemistry to prepare for the exam.
• Resources: Detailed videos, study guides, and practice exams available at UltimateReviewPacket.com.

Unit 1: Atomic Structure and Properties

Mass Spectrometry

• Graphs display isotopes as bars; x-axis shows atomic mass, y-axis shows percentage abundance.
• Example: Rubidium isotopes with masses of 85 and 87.
• Calculate average atomic mass and identify elements by matching with the periodic table.

Periodic Trends

• Atomic Radius: Largest at bottom left of the periodic table.
• Ionic Radius: Cations are smaller than anions.
• Ionization Energy: Highest at top right of the periodic table.

Photoelectron Spectroscopy

• Graphs represent electron sublevels (1s, 2s, etc.); height of peaks indicates number of electrons.

Unit 2: Molecular and Ionic Compound Structure and Properties

Lewis Structures

• Central atom placement, use eight valence electrons.
• Examples: Sulfur difluoride (SF2), CO2.

Hybridization and Molecular Geometry

• Hybridization determined by sigma bonds and unshared pairs (e.g., SP3, SP2).
• Molecular geometry affects polarity and intermolecular forces.

Unit 3: Intermolecular Forces and Properties

Intermolecular Forces

• Types: London dispersion, dipole-dipole, hydrogen bonding.
• Ionic compounds have ionic forces and may exhibit ion-dipole forces in solution.

Gas Laws

• Use ideal gas law to calculate moles, pressures, volumes, and temperatures.

Unit 4: Chemical Reactions

Net Ionic Equations

• Write ions separately in aqueous solutions; omit spectator ions.

Stoichiometry

• Three steps: convert to moles, use mole ratio, convert to desired unit.

Unit 5: Kinetics

Rate Laws

• Determine reaction order using experimental data.
• Rate law formula: Rate = k[A]^m[B]^n.

Reaction Mechanisms

• Identify intermediates, write overall equations.
• Slow step determines rate law.

Unit 6: Thermodynamics

Specific Heat and Enthalpy

• Use q = mcΔT for heat calculations.
• Enthalpy changes during phase changes: melting, boiling.

Unit 7: Equilibrium

Equilibrium Expressions

• Write Kc and Kp expressions omitting solids and liquids.
• Use ICE tables to solve equilibrium problems.

Le Châtelier’s Principle

• Predict shifts in equilibrium with changes in concentration, pressure, volume, temperature.

Unit 8: Acids and Bases

pH and pOH Calculations

• Use pH = -log[H3O+] and pOH = -log[OH-].
• Relationship: [H3O+][OH-] = 1.0 x 10^-14 at 25°C.

Titrations

• Analyze titration curves to find equivalence, half-equivalence points.

Unit 9: Applications of Thermodynamics

Entropy and Gibbs Free Energy

• Entropy (ΔS): Measure of disorder. Predict ΔS sign based on phase/state changes.
• Gibbs Free Energy (ΔG): Determines spontaneity. ΔG = ΔH - TΔS.

Electrochemistry

• Galvanic cells: Calculate cell potential, identify anode and cathode.

Conclusion

• Encouragement to continue studying using available resources.
• Reminder to check comprehensive video guides for deeper understanding of topics.