Physical Properties:
* Definition: These properties can be observed or measured without changing the substance's chemical makeup.
* Examples:
* Color: The appearance of a substance (e.g., blue, red, green)
* Odor: The smell of a substance (e.g., sweet, pungent, sour)
* Melting point: The temperature at which a solid changes to a liquid.
* Boiling point: The temperature at which a liquid changes to a gas.
* Density: The ratio of mass to volume.
* Hardness: The resistance to scratching or indentation.
* Solubility: The ability of a substance to dissolve in a solvent.
* Conductivity: The ability to conduct heat or electricity.
Chemical Properties:
* Definition: These properties describe how a substance reacts with other substances or changes its chemical composition.
* Examples:
* Flammability: The ability of a substance to burn in the presence of oxygen.
* Reactivity: How readily a substance reacts with other substances.
* Oxidation: The reaction of a substance with oxygen.
* Corrosion: The gradual destruction of a material by chemical reactions.
* Combustion: The rapid reaction between a substance and oxygen, producing heat and light.
* Decomposition: The breakdown of a substance into simpler substances.
Key Differences:
* Change in Composition: Physical changes do not alter the chemical makeup of a substance, while chemical changes result in new substances being formed.
* Reversibility: Physical changes are often reversible (e.g., freezing water into ice), while chemical changes are generally irreversible (e.g., burning wood).
* Energy Changes: Chemical changes typically involve significant energy changes, such as heat being released or absorbed, whereas physical changes may involve smaller energy changes.
Example:
* Water:
* Physical Properties: Colorless, odorless, liquid at room temperature, boils at 100°C.
* Chemical Properties: Reacts with sodium to produce hydrogen gas, can be decomposed into hydrogen and oxygen by electrolysis.
In summary, physical properties can be observed without changing the substance's chemical composition, while chemical properties involve changes in the substance's chemical makeup.
