The word traveled from al-kimiya, the Arabic art of transmutation, into medieval Latin alchimia, then chemistry. The al- is simply the Arabic article "the." Alchemy was a real experimental tradition, and chemists like Boyle grew out of it.
Assessment: The transmission path is documented. Alchemy was protoscience, not mere superstition.
Stories
Named for Egypt, the black land
One etymology derives kimiya from Kemet, the ancient Egyptian name for Egypt, meaning the black land, after its fertile Nile soil. Chemistry would then mean "the Egyptian art." A rival derives it from Greek kheein, to pour.
Assessment: Both roots are plausible; neither is settled. One of science's core words genuinely has an open etymology.
Interesting claims
The black land's hidden metallurgy
The claim: al-kimiya names Egypt because Egypt possessed the lost art, gold-making, glass-making, the transmutation knowledge of the temple workshops, and Arabic alchemy was the salvage operation of a destroyed Egyptian science.
Assessment: The Egyptian name is documented; the lost science is not. Egyptian artisans were genuinely masterful with glass, dyes, and metals, which is evidence enough for skill and none for transmutation. The claim upgrades craftsmanship to magic, as usual without a receipt.
Sources and further reading
Zosimos of Panopolis, On the Letter Omega, c. 300 CE, earliest extant chemeia usage
OED, chemistry, from medieval Latin alchimia via Arabic al-kīmiyā
Worth asking
If even chemistry's name is unresolved, how much of the periodic table of certainty is still pending?