1. Chapter 2 “Matter and Change” p. 38

2. Describing Matter Properties: 1)Extensive 1)Extensive – depends on amt of matter in sample - ex’s. mass, volume, calories, magnetism 2)Intensive 2)Intensive – depends on type of matter, not amt. -Hardness, Density, B.P. -All samples of same substance have same intensive prop’s. (same composition)

3. 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.

4. States of matter 1)Solid- cannot flow (definite shape & volume) 2)Liquid- definite vol - takes shape of container (flows) 3)Gas- w/o definite vol or shape & flows ◦Vapor- gaseous but normally liquid or solid @ room temp  water “gas”, or water “vapor”?

5. Three Main Phases – page 41

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

7. 4 th state: Plasma - formed at hi temps; ionized phase of matter (Sun)

8. Solid Liquid Gas Melt Evaporate Condense Freeze Sublime

9. Physical vs. Chemical Change Physical 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 Chemical change - change where new substance formed ◦Rust, burn, decompose, ferment

10. Section 2.2 Mixtures p. 44 Mixtures - physical blend of 2+ substances & have variable comp. 1)Heterogeneous – not uniform in comp Chocolate chip cookie, gravel, soil 2)Homogeneous - same comp thruout called “solutions” Kool-aid, air, salt water Every part keeps own prop’s.

11. 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), etc. Classified based on distribution of their components

12. 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

13. 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

14. Separation of a Mixture Components of dyes such as ink may be separated by paper chromatography.

15. Separation of a Mixture Distillation: takes advantage of different boiling pts. NaCl boils at 1415 o C H 2 O boils at 100 o C Mg boils at 1107 o C

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

17. Elements- simplest kind of matter ◦cannot be broken down & still have props of that element! ◦all one kind of atom Cmpds - broken down only by chemical methods ◦when broken down, pieces have diff. props. than original cmpd ◦made of 2+ atoms, chemically combined (not just a physical blend!)

18. Compound vs. Mixture CompoundMixture Made of one kind of material Made of more than one kind of material Made by a chemical change Made by a physical change Definite composition Variable composition

19. Which is it? Element Compound Mixture

20. Elements vs. Compounds Cmpds can be broken down into simpler substances by chemical means….elements can’t A “chemical change” is a change that produces matter with diff. composition than original matter

21. Chemical Change 1+ substances are converted into different substances. Heat & light often indicate chem change.

22. Properties of Compounds different from component elements. cmpd has new props: Table sugar – carbon, hydrogen, oxygen Table Salt – sodium, chlorine Water – hydrogen, oxygen

23. Classification of Matter

24. Symbols & Formulas Currently, 117 elements 1 or 2 letter symbol cmpds have formula Element’s 1 st letter always CAP; if 2 nd letter, lowercase ◦B, Ba, C, Ca Some names Latin ◦Table 2.2, page 52

25. Chemical Changes Chemical property - ability of substance to undergo specific chem change Fe + O forms rust rusting is chem prop of Fe During chem chge (also chemical rxn), comp of matter always changes.

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

27. Recognizing Chemical Changes 1)Energy absorbed/released (temp changes hotter/colder) 2)Color changes 3)Gas production (bubbling, fizzing, or odor change; smoke) 4)formation of precipitate - solid separates from solution (won’t dissolve) 5)Irreversibility - not easily reversed Some examples of these that are not chemical – boiling water bubbles, choc syrup in milk, etc.

28. Conservation of Mass During any chem rxn, products mass always = reactants mass All mass accounted for: ◦Burning of wood results in products that appear to have less mass as ashes…. ◦where is the rest? Law of conservation of mass

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