Question

is rubbing alchol a physical or chemical change

Answer 1

First, define the terms:
- A physical change alters a substance's physical form or state (evaporation, dissolving, mixing) without making new substances.
- A chemical change produces new substances by breaking/forming chemical bonds (combustion, oxidation, many reactions).

How that applies to rubbing alcohol (isopropyl alcohol):
- Evaporation or drying on skin: physical change.
- Mixing/dissolving in water: physical change.
- Disinfecting action (denaturing proteins, disrupting cell membranes): this is a biochemical/physicochemical effect that destroys microbes’ structures. It doesn’t typically create new chemical species of the alcohol, so it’s usually treated as a physical/biochemical effect rather than a classic chemical reaction.
- Burning (combustion) or oxidation of isopropyl alcohol (to acetone, etc.): chemical changes.

Short answer: most common things you see with rubbing alcohol (evaporation, dissolving, antiseptic action) are physical/biochemical effects; only when it chemically reacts (burns or is oxidized) is it a chemical change.