We learn about how a simple ethyl group can completely change a compound in Year 9. If a ninth grader can grasp that concept, then all she has to listen to is this: "Look, Jenny, that chemical and this compound are not the same thing at all, even if they have similar names or molecular groups. Do you think that water is the same as hydrogen and oxygen gas? Would you fill a blimp with water and expect it explode in a firey mess like the Hindenburg?"
Surely she can grasp that. Or maybe we should start talking about the spiritual vibrations of aryl groups, the dipole moments of their chakra or some shit. Maybe she'll get that.
Sorry, she just really annoys me.