Chem Notes Properties
Physical vs. Chemical Properties
Physical properties can be observed without changing the substance's identity.
Chemical properties can only be observed by changing the substance's chemical identity.
Density is a physical property.
Boiling point is a physical property.
Melting point is a physical property.
Solubility (how it dissolves) is a physical property.
Flammability is a chemical property.
Reactivity with water or acid is a chemical property.
Toxicity is a chemical property.
Intensive vs. Extensive Properties
Intensive properties do not depend on the amount of matter present.
Extensive properties change depending on the amount of matter present.
Density is an intensive property.
Temperature is an intensive property.
Color is an intensive property.
Mass is an extensive property.
Volume is an extensive property.
Length is an extensive property.
States of Matter (Microscopic View)
Solids have a definite shape and a definite volume.
Solid particles are tightly packed and vibrate in fixed positions.
Liquids have an indefinite shape but a definite volume.
Liquid particles are close together but can slide past each other.
Gases have an indefinite shape and an indefinite volume.
Gas particles are far apart and move rapidly in random directions.
Physical vs. Chemical Changes
Physical changes alter the form of a substance but not its chemical identity.
Chemical changes create entirely new substances with new chemical properties.
Phase changes (melting, boiling, freezing) are always physical changes.
Dissolving sugar in water is a physical change.
Burning wood is a chemical change.
Rusting iron is a chemical change.
Color changes often indicate a chemical change.
Gas bubble formation often indicates a chemical change.
Precipitate formation (solid forming from liquids) indicates a chemical change.
Temperature changes without outside heating indicate a chemical change.