AP®︎ Chemistry Unit 9: Notes & Study Guide

Prepare for your quiz, test, or the AP exam with a comprehensive review on Unit 9 of AP Chemistry – Thermodynamics and Electrochemistry.

Exam weight: 7%–9%
11 Topics

Unit 9: Thermodynamics and Electrochemistry

What makes reactions favorable, how entropy and enthalpy combine to drive change, and how chemical energy converts to electrical energy.

Begin with Topic 9.1: Introduction to Entropy

To review Unit 9, go through each of the 11 topics below.

Everything you actually need to know for your Unit 9 test, pulled directly from the AP® Chemistry curriculum.

Topic 9.1
~6 min
Review
Introduction to Entropy
Introduction to Entropy
  • What Entropy Is
  • The Main Ways Entropy Changes
  • Predicting Sign and Relative Magnitude of ΔS
Review
Topic 9.2
~6 min
Review
Absolute Entropy and Entropy Change
Absolute Entropy and Entropy Change
  • What Absolute Entropy Is
  • The ΔS° Reaction Formula
  • What Determines the Size of S° for a Substance
Review
Topic 9.3
~5 min
Review
Gibbs Free Energy and Thermodynamic Favorability
Gibbs Free Energy and Thermodynamic Favorability
  • Gibbs Free Energy and What ΔG° Means
  • The Equation That Connects Enthalpy and Entropy
  • All Possible ΔH° and ΔS° Combinations
Review
Topic 9.4
~6 min
Review
Thermodynamic and Kinetic Control
Thermodynamic and Kinetic Control
  • Thermodynamic Favorability vs Reaction Rate
  • Activation Energy and the Energy Barrier
  • What Kinetic Control Means
Review
Topic 9.5
~5 min
Review
Free Energy and Equilibrium
Free Energy and Equilibrium
  • What Thermodynamically Favored Means
  • The Mathematical Relationship Between ΔG° and K
  • Estimating K from the Size of ΔG°
Review
Topic 9.6
~6 min
Review
Free Energy of Dissolution
Free Energy of Dissolution
  • What Free Energy of Dissolution Is
  • The Three Energy Changes in Dissolution
  • Enthalpy of Dissolution
Review
Topic 9.7
~7 min
Review
Coupled Reactions
Coupled Reactions
  • What Makes a Reaction Thermodynamically Favorable or Unfavorable
  • Two Ways to Drive a Thermodynamically Unfavorable Reaction
  • How Reaction Coupling Works
Review
Topic 9.8
~7 min
Review
Galvanic (Voltaic) and Electrolytic Cells
Galvanic (Voltaic) and Electrolytic Cells
  • What an Electrochemical Cell Is
  • The Components of an Electrochemical Cell and What Each Does
  • Galvanic vs Electrolytic Cells
Review
Topic 9.9
~5 min
Review
Cell Potential and Free Energy
Cell Potential and Free Energy
  • Cell Potential and What It Means
  • Standard Reduction Potentials and Calculating E°cell
  • From Cell Potential to Spontaneity and ΔG°
Review
Topic 9.10
~6 min
Review
Cell Potential Under Nonstandard Conditions
Cell Potential Under Nonstandard Conditions
  • What Cell Potential Under Nonstandard Conditions Means
  • The Reaction Quotient Q in Electrochemical Cells
  • The Nernst Equation and What It Tells You
Review
Topic 9.11
~5 min
Review
Electrolysis and Faraday’s Law
Electrolysis and Faraday’s Law
  • Electrolytic Cells and Nonspontaneous Redox
  • Galvanic vs. Electrolytic Cells
  • Faraday’s Law and the Charge–Mass Relationship
Review

Notes

1 credit used · 5/5 remaining