Reaction Mechanisms & Energy Profiles – AP Chemistry

Learning Objectives

Analyze potential energy profiles for 1-step and 2-step reactions.

Identify Transition States (Peaks) and Intermediates (Valleys).

Observe how Catalysts strictly lower Activation Energy (\( E_a \)) without changing \( \Delta H \).

Thermodynamics vs Kinetics

\( \Delta H \) determines if a reaction is Exothermic (heat released) or Endothermic (heat absorbed). \( E_a \) determines the reaction rate speed.

Multi-Step Reactions

The overall reaction rate is dictated by the Rate-Determining Step (Slow Step), which corresponds to the highest Transition State energy peak.