Chapter 2 “Matter and Change” p. 38

Describing Matter Properties: Extensive – depends on amt of matter in sample - ex’s. mass, volume, calories, magnetism Intensive – depends on type of matter, not amt. Hardness, Density, B.P. All samples of same substance have same intensive prop’s. (same composition)

Identifying Substances Physical Properties- observed & measured w/o changing composition color, hardness, m.p., b.p. Chemical Properties- observed by changing comp of material ability to burn, decompose, ferment, react w/, etc.

Solid- cannot flow (definite shape & volume) States of matter Solid- cannot flow (definite shape & volume) Liquid- definite vol - takes shape of container (flows) Gas- w/o definite vol or shape & flows Vapor- gaseous but normally liquid or solid @ room temp water “gas”, or water “vapor”?

Three Main Phases – page 41

States of Matter Definite Volume? Definite Shape? Solid Liquid Gas Result of a Temperature Increase? Definite Volume? Definite Shape? Will it Compress? Small Expans. Solid YES YES Not easily Small Expans. Liquid Not easily NO YES Large Expans. Gas NO NO YES

4th state: Plasma - formed at hi temps; ionized phase of matter (Sun)

Sublime Condense Freeze Evaporate Melt Solid Liquid Gas

Physical vs. Chemical Change Physical change changes visible appearance w/o changing comp of material Boil, melt, cut, bend, split, crack Is boiled water still water? Reversible, or irreversible Chemical change - change where new substance formed Rust, burn, decompose, ferment

Section 2.2 Mixtures p. 44 Mixture - physical blend of 2+ components Heterogeneous – uniform in comp Choc chip cookie, gravel, soil Homogeneous - same comp thruout (solutions) Kool-aid, air, salt water Every part keeps own prop’s

Solutions - homogeneous mixtures Mixed molecule by molecule, so too small to see diff pts occurs btwn any state of matter: gas-gas; liquid-gas; gas-liquid; solid-liquid; solid-solid (alloys) Steel (Fe, Cr & Ni)

Phase? “phase” describes any pt of sample w/ uniform comp of properties A homogeneous mixture consists of a single phase A heterogeneous mixture consists of two or more phases. Note Figure 2.6, page 45

Differences in physical props used to separate mixtures Separating Mixtures Some by physical means: rocks & marbles, iron filings & sulfur (magnet) Differences in physical props used to separate mixtures Filtration - separates solid from liquid in hetero mix. (by size) – Figure 2.7, page 46

Separation of a Mixture Distillation: takes advantage of different boiling pts. NaCl boils at 1415 oC H2O boils at 100 oC Mg boils at 1107 oC

Separation of a Mixture Components of dyes such as ink may be separated by paper chromatography. Forensic Ink Analysis Chromatography video

Applications of Chromatography 2 Greek words: chroma "color" and “graphein "to write" Biological labs: ID amino acids detects drugs in urine Environmental labs: ID contaminants in waste oil pesticides in groundwater test drinking water & test air quality Pharmaceutical companies prepare quantities of extremely pure materials. Food industry ID contaminants like aflatoxin naturally occurring toxin produced by fungus

Sec 2.3 Elements & Compounds p. 48 Substances are either: a) elements, or b) compounds

Compounds v.s. Mixtures

Which is it? Compound Mixture Element

Chemical Change Heat & light often indicate chem chg A “chemical change” chg producing matter w/ diff. comp than original matter 1+ substances are converted into different substances. Heat & light often indicate chem chg

Classification of Matter

Symbols & Formulas 118 elements 1 - 2 letter symbol 1st letter CAP; 2nd letter lowercase B, Ba, C, Ca Some names Latin Table 2.2, page 52 cmpds have formula H2O, NaCl, C12H22O11

Sec 2.4 Chemical Rxns p. 53 Chemical Changes Chemical property - ability of substance to undergo specific chem change Fe + O = rust rusting - chem prop of Fe During chem chge comp of matter always changes

Chemical Rxns are… When 1+ substances changed into new substances Reactants- start w/ Products- end w/ Products have NEW PROPS diff from reactants Arrow points from reactants to new products

Recognizing Chemical Changes Energy absorbed/released (temp changes hotter/colder) Color changes Gas production (bubbling, fizzing, or odor change; smoke) precipitate forms - solid separates from solution (won’t dissolve) Irreversibility - not easily reversed Some ex’s not chem – boiling water bubbles, choc syrup in milk, etc.

Law of conservation of mass During any chem rxn, product mass = reactant mass All mass accounted for: Burning wood results in products that appear to have less mass (ashes)…. CO2 & H2O vapor Law of conservation of mass

- Page 55 43.43 g Original mass = 43.43 g Final mass reactants = product

Using your online textbook: Due by Friday 9/22: Page 42 #1-7   Page 47 #11-16   Page 52 #20-27 Page 55 #28-34