* Physical Properties: These are characteristics of a substance that can be observed or measured without changing the substance's chemical composition.

* Freezing point: The temperature at which a liquid changes to a solid.

* Boiling point: The temperature at which a liquid changes to a gas.

* Density: The mass of a substance per unit volume.

* Chemical Properties: These describe how a substance interacts with other substances or how it changes its chemical composition.

* Reactivity: How readily a substance undergoes a chemical reaction.

In summary: Freezing point, boiling point, and density are all physical properties because they can be observed or measured without changing the chemical nature of the substance. Reactivity, on the other hand, describes a chemical change.