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 particlesSolid 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– 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– Separates liquid from solid

• Distillation– Separates liquid from liquid

• Chromatography‒ Separates solids