Quick Read: What Counts as a Property?
Physical properties can be observed or measured without changing the identity of the substance (e.g., density, melting point, boiling point, solubility, conductivity, malleability, luster). Measuring these does not create a new substance.
Chemical properties describe a substance’s ability to undergo changes that do form new substances (e.g., flammability, reactivity with acids, tendency to oxidize or tarnish, ability to decompose). Testing these usually changes the substance.
Tip: If the identity stays the same → physical. If a new substance forms → chemical.