* Chemical Properties describe how a substance reacts with other substances, or its ability to change into a new substance. The formula of an oxide tells us the specific elements and their ratio in a compound, which directly relates to its chemical composition and how it interacts with other chemicals.

* Physical Properties are characteristics that can be observed without changing the substance's chemical composition. Examples include color, density, melting point, etc.

Example:

* Iron Oxide (Fe₂O₃): The formula tells us that this compound is made of iron and oxygen in a specific ratio. This determines its reactivity, such as its ability to rust. This is a chemical property.

* Color of Iron Oxide (Red/Brown): The color of iron oxide is a physical property, as it doesn't change the chemical composition of the substance.