Week 8: Reaction Kinetics

Why a small rise in oven temperature browns Peking duck skin much faster than the temperature difference alone suggests — the Arrhenius equation.

19 April 2027

Outline#

• Recap: Module 3 gave us a transition’s heat cost; this lecture gives a transition — or here, a reaction — its rate, and the two questions are distinct even when they describe the same pot.
• Building the Arrhenius equation from its two pieces: a temperature- independent prefactor and an exponential term carrying the activation energy, then reading what a higher activation energy actually means for how sharply rate responds to temperature.
• Worked comparison: Peking duck skin browning faster at a higher oven temperature than the temperature gap alone would predict, because browning’s activation energy makes it unusually temperature-sensitive.
• Comparing two food reactions with different activation energies side by side, to show that “cook it hotter” doesn’t speed up every reaction by the same factor.
• Setting up Module 9: a reaction proceeding at a rate is one kind of change during cooking; a material crossing a phase or state boundary is another, and the next lecture keeps them separate on purpose.