- Solid moth balls gradually vaporize in a closet
- Physical
- Change
- The moth balls change from solid to gas without altering their chemical composition; this is sublimation, a physical change.
- Hydrofluoric acid attacks glass and is used to etch calibration marks on glass laboratory utensils
- Chemical
- Change
- Hydrofluoric acid reacts with silica in glass to form new compounds, permanently altering the material’s chemical structure.
- A French chef making a sauce with Brandy is able to boil off the alcohol from the brandy, leaving just the brandy flavor
- Physical
- Change
- Boiling removes alcohol by evaporation based on differences in boiling points; no new substances are formed, only separation of components.
- Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills
- Chemical
- Change
- Acids react with cellulose in cotton, breaking down its molecular structure and creating holes — a chemical reaction that alters the fabric’s composition.
- The cutting of food
- Physical
- Change
- Cutting changes the size and shape of food but does not alter its chemical identity or create new substances.
- In the iodine clock reaction two clear solutions are mixed together and turn a startling black color after a few minutes of mixing
- Chemical
- Change
- The color change results from a chemical reaction forming a new compound (iodine-starch complex), indicating a change in chemical composition.
- A blue sports drink is mixed with a red berry juice to make a purple mixed drink
- Physical
- Change
- Mixing two liquids creates a new color through physical blending; no chemical reaction occurs, and the original substances remain chemically unchanged.
Parent Tip: Review the logic above to help your child master the concept of worksheet on chemical vs physical properties and changes.
