AP Chemistry Final Review with Jeremy Kug

Introduction

• Purpose: Cram session for AP Chemistry exam
• Resources:
  • Free guided notes PDF available
  • Comprehensive resources at ultimatereviewpacket.com
  • Coverage: Units 1-9

Unit 1: Chemical Foundations

Mass Percent

• Concept: Calculate mass percent of elements in a compound
• Steps:
  1. Find atomic masses of elements
  2. Calculate total molar mass
  3. Divide element mass by total mass, then multiply by 100
• Examples:
  • Magnesium Chloride (MgCl₂)
  • Calcium Chloride (CaCl₂)
  • Trends: Lighter metals result in higher percentage of chloride

Mass Spectrometry

• Purpose: Identify isotopes and calculate average atomic mass
• Graph Interpretation:
  • Bar heights indicate abundance
  • Calculate average atomic mass by weighing isotopic masses

Electron Configurations

• Writing Configurations: Start from the beginning of the periodic table
• Examples: Chlorine atom, chloride ion, aluminum atom, aluminum ion
• Trends: Atomic radius decreases across a period, increases down a group

Atomic Radius and Ionic Radius

• Atomic Radius: Largest at bottom left of periodic table
• Ionic Radius:
  • Cations smaller than anions
  • Isoelectronic ions compared by proton count

First Ionization Energy

• Trend: Increases across a period, decreases down a group

Photoelectron Spectroscopy

• How to Read: Peaks correspond to sublevels
• Height: Number of electrons

Unit 2: Molecular and Ionic Compound Structure and Properties

Lewis Structures

• Method: Central atom in center; follow octet rule
• Examples: SF₂, CO₂

Sigma and Pi Bonds

• Types:
  • Single bond: 1 sigma
  • Double bond: 1 sigma, 1 pi
  • Triple bond: 1 sigma, 2 pi

Molecular Geometry and Bond Angles

• Examples: Bent, trigonal planar, tetrahedral
• Bond Angles: Tetrahedral ~109.5°, planar ~120°, bent ~104.5°

Polarity

• Concept: Presence of a dipole moment indicates polarity
• Forces: London dispersion, dipole-dipole, hydrogen bonding

Melting Points

• Factors:
  • Charge: higher charges increase melting point
  • Ion size: smaller ions have higher melting points
• Comparison: Sodium chloride vs sodium sulfide

Unit 3: Intermolecular Forces and Properties

Gas Laws

• Equation: PV = nRT
• Calculation: Using pressure, volume, temperature, solve for moles

Spectrophotometry

• Beer-Lambert Law: Used to determine concentration from absorbance
• Graph Interpretation: Match absorbance to concentration on calibration curve

Unit 4: Chemical Reactions

Net Ionic Equations

• Method: Omit spectator ions
• Example: Magnesium metal reacting with copper(II) chloride

Stoichiometry

• Three-Step Process: Convert to moles, use mole ratio, convert to grams

Unit 5: Kinetics

Rate Laws

• Determining Orders: Compare rate changes with concentration changes
• Graphical Method: Identify straight line to determine order

Reaction Mechanisms

• Steps: Identify rate-determining step, write rate law

Unit 6: Thermodynamics

Calorimetry

• Equation: Q = mCΔT
• Problem Solving: Calculate heat transferred, temperature changes

Heating Curves

• Phases: Solid, liquid, gas transitions and temperature changes

Unit 7: Equilibrium

Equilibrium Expressions

• Equations: Products over reactants, exclude solids and liquids

Le Châtelier's Principle

• Changes: Effects of adding/removing substances, changing volume, temperature

Unit 8: Acids and Bases

pH and pOH

• Equations: pH = -log[H⁺], pOH = -log[OH⁻]
• Relationship: pH + pOH = 14 at 25°C

Strong Acids and Bases

• Strong Acids: HCl, HBr, HI, HNO₃, H₂SO₄, HClO₄
• Strong Bases: Group 1 and 2 hydroxides

Weak Acids and Bases

• Equilibrium: Solve using ice box method

Titration Curves

• Interpretation: Equivalence point, half-equivalence point (pKa = pH)

Unit 9: Applications of Thermodynamics

Entropy

• Concept: Measure of disorder or energy dispersal
• States of Matter: Solids < liquids < gases

Thermodynamic Favorability

• Gibbs Free Energy: ΔG = ΔH - TΔS
• Criteria: Negative ΔG indicates favorability

Electrochemistry

• Galvanic Cells: Battery, thermodynamically favorable
• Electrolytic Cells: Requires external energy, non-favorable
• Cell Potential: Calculate using standard reduction potentials

Conclusion

• Focus: Remember learned concepts and apply them effectively in the exam
• Motivation: Trust in preparation and aim to succeed in the AP exam