Properties, Changes & Classification of Matter

1. Properties, Changes & Classification of Matter

2. 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

3. 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

4. Intensive properties: Propertiesdo 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

5. 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

6. 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

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

8. Classification of Matter

10. 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

11. 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

12. Which is heterogeneous or homogenous?

13. Decide • Element? Compound? Homogeneous or heterogeneous mixture?

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