Why properties of a substance determine how that substance is will react when combined with other substance

It is the chemical properties of a substance, which determines that how the substance will react when combined with other substance.  

The usual properties of a substance like density, color, and hardness are some of the illustrations of physical properties. The properties, which illustrates that how a substance modifies into a completely distinct substance are known as chemical properties.  

Some of the examples of chemical properties are oxidation, toxicity, the heat of combustion, and flammability, enthalpy of formation, radioactivity, and chemical stability under particular conditions.  

the endomembrane system i think