Slow vs Fast

[505997354]

Hello, I remember Lavelle giving an analogy about brownies on what reaction speed to focus on, what exactly was that analogy?

[Charlotte Norris 2K]

I don't remember the analogy exactly the reason that the slow step controls the reaction rate is because in any production, you can only complete the entire process as fast as the slowest step. E.g. if a group of people are putting together a presentation, even if every other person in the group takes two hours, if the last person takes 4 hours the presentation will only be complete after 4 hours (assuming you are all working at the same time).

[005917072]

if multiple people are working together to make brownies, each person doing a different step, the rate at which the brownies will be made is determined by the person who takes the longest to do their step. it doesn't matter if everyone else does their step extremely quickly, they won't get made until the slowest person has completed their step. this compares to reaction rates because the slowest step in the reaction determines the rate constant (and thus, the reaction rate) of the entire reaction.

[Isaac 14B]

I don't recall the mention of brownies as an example but the understanding of slow/fast reactions is actually quite straightforward. We are to look for our slowest partial reaction (will always be given to us) and use that as the basis for all related rate laws. Our reaction can only be as fast as the slowest components (they are in essence limiting factors to our speed).

[505900922]

The slow reaction always determines the rate. He related it to car production. If the whole production of a car can be done in less than a day, but the wiring takes three days, the car won't be finished for three days. Therefore your rate relies on the slowest one.