Enantiomeric excess (EE) measures the imbalance between left-handed and right-handed versions of a molecule: a 50-50 mixture has 0% excess, while a pure single-handed sample has 100% excess. The hosts work through an example to show that a 60-40 mixture equals a 20% excess, since EE is the difference between the two amounts rather than the amount of the majority form. They note that a 51-49 split, a 2% excess, is close to a coin flip, setting up the later discussion of how small starting imbalances can grow much larger.
202 words · auto-generated from the episode video
29:14there's one scientific like, parameter that I need to introduce to everyone. And this is the idea of enantiomeric excess, abbreviated EE. This is the difference between the amount of left-handed stuff, and the amount of right-handed stuff. If I have exactly 50% left and right, that's a 0% excess, right? Because I have exactly the same. If I have all of 1%, all of one type, if I have all of like left-handed and no right-handed, that means I have 100% excess of left-handed stuff, right? This is a key thing, a key parameter that we're gonna have to deal with as we move on, okay?
29:54So, a 50-50% mixture, that's a zero. If I have a 60-40 mixture, that's a 20% excess, because it's really the difference between how much of one I have and how much of the other I have. And that distinction is essential as we get to talking about how a small starting imbalance is going to create a large ending imbalance. So, 2% excess is almost a coin flip? Yeah. And then 50, 51, 49 of the other? That's 2%, right? That's 2%. Yeah, and that's almost a coin flip. Okay okay okay okay okay.
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