Energy, Thermodynamics, and Chemical Reactions

  • Lesson/Note on Energy

    • Focus on first and second laws of thermodynamics, key energy concepts, and predicting spontaneous reactions.

  • Big Ideas

    • Metabolic processes involve chemical changes and energy conversions.
    • Understanding these processes aids decision-making regarding personal and environmental issues.

  • Energy Basics

    • All living things require constant energy flow; lack of energy sources leads to ecosystem decline.
    • Types of Energy:
    • Potential Energy: Stored energy based on position/arrangement.
    • Kinetic Energy: Energy of motion.

  • Laws of Thermodynamics

    • 1st Law: Energy cannot be created/destroyed, only converted.
    • 2nd Law: Energy transformations lead to increased disorder (entropy).

  • Enthalpy and Chemical Reactions

    • Enthalpy (H): Measure of heat energy.
    • Exothermic: Releases energy; usually spontaneous.
    • Endothermic: Absorbs energy; usually not spontaneous.
    • Predicting Spontaneity: Use Gibbs Free Energy (G), which determines reaction availability for work.
    • Exergonic (spontaneous, releases energy) vs. Endergonic (non-spontaneous, requires energy).

  • Gibbs Free Energy Equation:

    • ΔG = ΔH - TΔS
    • Understanding the signs and values of ΔG, ΔH, & ΔS helps predict spontaneity and energy exchanges.

  • Review Questions:

    1. Classify energy types (kinetic vs. potential).
    2. Describe the first and second laws of thermodynamics with examples.
    3. Explain melting ice as an increase in entropy.
    4. What is a spontaneous reaction, and how is it predicted?