Matter occurs as elements (pure), compounds (pure), and mixtures, which may be homogeneous (solutions) or heterogeneous. Matter is classified by its chemical and physical properties.
Physical properties refer to the condition or quality of a substance that can be observed or measured without changing the substance‘s composition. Important physical properties are density, conductivity, melting point, boiling point, freezing point, malleability, color, smell, opacity, viscosity, and ductility.
Chemical properties refer to the ability of a substance to undergo chemical reaction and form a new substance. Examples of chemical properties are: reactivity (the tendency of an element to enter into a chemical reaction) with water, heat of combustion, PH, and electromotive force.
The more properties we can identify for a substance, the better we know the nature of that substance. These properties can then help us model the substance and thus understand how this substance will behave under various conditions.
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