Hmm, most of what you described is physics (touch, temperature, moistness …) and it could happen on a first date. But chemistry as I understand it has to do with smelling, tasting, letting the other person’s bodily secretions (body scent, sweat, breath, cum, vaginal fluids etc.) into your own. If that happens on a first date, great! But most of it usually comes later, right? And then the exchange of hormones, not decoupled from pleasurable sex, creates chemical and neuronal pathways that bind us — so a whiff of their hair on a pillow, their unwashed underwear left for you, perhaps even a whiff of the underarms on a simple T-shirt, gets you all hot and bothered (during the early part of the relationship), every cell in your body striving to absorb some more of them, to reconnect, and later in the relationship, in addition, causes you to miss them as well as be soothed.
In my experience, in two or three relationships, with good physical attraction, when the chemistry hasn’t been there (before or after first having sex), the relationship, even sexual, has been very short-lived.
On the other hand, when I ask my partner to keep her panties or T-shirts and save them under my pillow, when I root through my laundry basket for her clothes and bury my face in them, I think I am being driven by chemistry.
Paraphrasing Natalie Angier from her book Woman: An Intimate Geography, “If you don’t want to fall in love with a woman, don’t suck her!”.