But we have molecules.

We know there are atoms and molecules.

So we won't do it for this molecule, but we'll go back and do it for some of our other examples, and you can go back and do it for this one.

An infinitesimal amount, to look at the derivative. Once I do this, how many molecules are in this higher level now?

And because, of course, we have this carbon here what you end up doing is adding a carbon to your molecule.