Properties, Changes & Classification of Matter

Properties vs. Changes Properties: Describing a substance as seen, smelled, felt, measured, or if it can react with other substances Physical vs. chemical properties Intensive vs. extensive properties Changes: Describing what is or can be done to a substance Physical vs. chemical changes

Properties Physical properties: describing the substance’s appearance such as color, smell, texture, state (liquid, gas, solid), ductility, malleablility, boiling point, freezing point, etc ** ductility: Making into wire ** malleability: Pounding to sheets (Ex) Copper has high ductility and malleability while glass doesn’t Chemical properties: describing if a substance will react with other substances (Ex) Gasoline burns while water doesn’t because they have different chemical properties **Burning is to combine with oxygen ** Properties can identify a substance

Intensive properties: Properties do not depend on the amount of the substance (Ex) color, boiling point, state, texture, freezing point, density, etc Extensive properties: Properties depend on the amount of the substance (Ex) mass, volume ** mass: the amount of substance or called weight in chemistry ** volume: the amount of space taken up by an object

Changes Physical changes: do not change the substance’s composition (Ex) tearing, pounding, boiling, freezing, melting *Many physical changes are reversible while some are irreversible Chemical changes: change the substance’s composition (Ex) burning, fermentation, digestion (Ex) Why isn’t boiling a chemical change? *Most chemical changes are irreversible *Chemical changes also accompany physical changes

States Three common states on Earth: solid, liquid, and gas (≈vapor) *Plasma is the most common in Universe Depend on the amount of space between particles and how much the particles move http://www.pbs.org/wgbh/nova/zero/matt-flash.html Space between particles Motion of particles Solid A very little space Vibrate but can’t move out of their place Liquid Some space Move out of their place Gas Lots of space Move around a lot and fast

States can change by changing temperature and/or pressure Melting  freezing (solid ↔ liquid) Boiling  condensation (liquid ↔ gas) Sublimation  deposition (solid ↔ gas)

Classification of Matter

Pure substance Mixture Has the same composition throughout Elements or compounds Elements all on the periodic table Each element is made up of one kind of atom Compounds formed by chemically combining two or more elements Each compound is made of at least two different kinds of atoms Mixture Made of two or more substances mixed Heterogeneous or homogeneous

Heterogeneous vs. Homogenous Mixtures Heterogeneous mixtures Not well evenly mixed Two or more phases are visible (Ex) oil and water mixture Homogeneous mixtures Evenly well mixed Appears to be one phase Also called as solution *Mixtures can be separated by filtration, distillation, chromatography, or other separation methods

Which is heterogeneous or homogenous?

Decide Element? Compound? Homogeneous or heterogeneous mixture?

Separation Methods Filtration or evaporation Distillation Separates liquid from solid Distillation Separates liquid from liquid Chromatography Separates solids