Which characteristic of a substance is considered a chemical property? its boiling point its reactivity its density its conductivity

Examples of chemical properties are: heat of combustion, clammability and corrosion/oxidation resistance, reactivity with water, PH, and electromotive force. The difference between a physical and chemical property is straightforward until the phase of the material is considered.
                                                                                                                  chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter. They include reactivity, flammability, and the ability to rust. Reactivity is the ability of matter to react chemically with other substances.

Just say reactivity bruh im tryna pass