Chemistry and Product Knowledge
Matter, pH, and mixing
Matter runs elements → atoms → molecules → compounds. A solution is uniform, a suspension has particles that settle, and an emulsion blends oil and water with a surfactant. The pH scale runs 0–14: 7 is neutral, below 7 is acidic, above 7 is alkaline. Skin and nails prefer mildly acidic products; strong alkalis swell and soften the plate.
Products to recognize
Acetone and ethyl acetate (solvents, flammable), isopropyl alcohol (dehydrating), hydrogen peroxide (oxidizer), sodium hydroxide and ammonium thioglycolate (strong alkalis in depilatories and wave products), nitrocellulose and toluene (polish), formaldehyde (hardener, restricted), cyanoacrylate (dip and glue). Polymerization is the chemical joining of monomers into polymers; catalysts and initiators start the reaction; gel systems use photoinitiators activated by UV/LED light.
Chemical safety
Read and keep the Safety Data Sheet, never transfer product to an unlabeled bottle, never mix products not designed to be mixed, keep lids closed, ventilate, store away from heat and flame, and know the difference between flammable and combustible.
Disinfectant chemistry
Quaternary ammonium compounds, phenolics, and sodium hypochlorite (bleach, typically 1:10 for blood spills) are common; each is diluted and timed per its label, and mixing bleach with ammonia or acids creates dangerous gas.
Worked example: a product labeled pH 3 is acidic and tightens the cuticle; pH 9 is alkaline and can soften and dull the plate. Check pH before assuming a product is gentle.
Rule of thumb: if you would not put it on your own skin at that strength, thin it, ventilate, and glove up.