Key Takeaways
Lesson Description
Key Takeaways
• Thermodynamics studies energy changes during chemical reactions.
• Endothermic reactions absorb heat (ΔH > 0).
• Exothermic reactions release heat (ΔH < 0).
• Potential energy diagrams illustrate energy changes during reactions.
• Hess's Law states that total enthalpy change is independent of reaction pathway.
• Bond enthalpy can be used to estimate reaction enthalpy.
• Entropy (ΔS) measures disorder in a system.
• Gibbs Free Energy determines whether a process is spontaneous.
Must Know Equations
ΔH = Σ(Bonds Broken) − Σ(Bonds Formed)
ΔG = ΔH − TΔS
Must Know Vocabulary
Enthalpy
Entropy
Gibbs Free Energy
Spontaneous Process
Endothermic
Exothermic
Hess's Law
Bond Enthalpy
AP Exam Focus
• Interpret potential energy diagrams.
• Apply Hess's Law to calculate ΔH.
• Predict spontaneity using ΔG, ΔH, and ΔS.