What actually happens to a chemical reaction when you add a catalyst — does it change the products, or just the path to get there? I teach high school chemistry, and every year a student asks whether a catalyst gets "used up," and I have to explain that it participates but is regenerated, which is why a tiny amount of manganese dioxide can decompose liters of hydrogen peroxide. The part I'm less sure about is how well students transfer this to biology: enzymes are just protein catalysts, and the same logic applies, yet many still think enzymes are consumed. So I want to know whether teaching reaction rates separately from equilibrium helps or hurts. If a student can calculate activation energy but can't explain why the catalyst is still there at the end, have they really understood catalysis?