Physical Properties
* Definition: Characteristics of a substance that can be observed or measured without changing the substance's chemical composition.
* Examples:
* Color: The appearance of a substance (e.g., blue, green, red).
* Odor: The smell of a substance (e.g., sweet, pungent, odorless).
* Density: The mass per unit volume of a substance (e.g., grams per cubic centimeter).
* Melting point: The temperature at which a solid changes to a liquid.
* Boiling point: The temperature at which a liquid changes to a gas.
* Solubility: The ability of a substance to dissolve in another substance.
* Hardness: The resistance of a substance to scratching or indentation.
* Conductivity: The ability of a substance to conduct heat or electricity.
* State of matter: Whether a substance is solid, liquid, or gas.
* Key Points:
* Can be observed or measured without changing the substance's chemical makeup.
* Often used to identify and characterize substances.
* Can be reversible (e.g., ice melting to water, which can then freeze back into ice).
Chemical Properties
* Definition: Characteristics of a substance that describe how it reacts with other substances or how it 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.
* Corrosion: The tendency of a substance to deteriorate or break down due to chemical reactions with its environment.
* Acidity: The tendency of a substance to donate hydrogen ions (H+).
* Basicity: The tendency of a substance to accept hydrogen ions (H+).
* Key Points:
* Involve a change in the chemical composition of the substance.
* Typically require chemical reactions to be observed.
* Often irreversible (e.g., burning wood changes it to ash and gases).
In Summary
Think of it like this:
* Physical properties: What a substance *is* (color, shape, density).
* Chemical properties: What a substance *does* (reacts with, burns, corrodes).
