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Text book resources. http://edugen.wiley.com/edugen/class/cls112693. What is Chemistry ?. Study the Characteristics , Composition , and Transformation of MA TT ER What is MA TT ER ? has MASS and VOLUME. Properties of MATTER ?. Physical Properties :
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Text book resources • http://edugen.wiley.com/edugen/class/cls112693
What is Chemistry ? • Study the Characteristics, Composition, and Transformation of MATTER What is MATTER? has MASS and VOLUME
Properties of MATTER ? • Physical Properties: Color, mass, volume, hardness, Physical States of Water: (S, L, G), bp, mp • Chemical Properties: reactivity, thermal stability Intensive vs. extensive properties: relation with sample size
0 Which one of the following is an extensive property of matter? 1) density 2) specific gravity 3)electrical conductivity 4) refractive index 5) mass
MATTER Transformation • Physical Change: Change of physical states: Solid to liquid • Chemical Change: Change of composition or (identity): Decomposition, reaction with other compounds
0 Which one of the following is a chemical change? 1) when a blood stain is washed with 3% hydrogen peroxide solution, it changes color 2) when a solid stick of butter is heated, it becomes a liquid 3) when blue paint is mixed with yellow paint, a green color is obtained 4) when a bar of gold metal is pounded with a hammer, it flattens out
MATTER Classification • Pure substance, has only one chemical identity • Mixtures: many Pure substances mixed. Can be separated into Pure substance by physical change: --Heterogeneous mixtures, two or more phases: solids/liquids mixtures, --Homogeneous mixtures, -one phase solutions, gases mixtures Matter relations
Pure Substances • Elements: one kind particle, unbreakable through chemical change: 117 elements found: iron, cupper, gold • Compounds: two or more different kinds of particles can be broken into elements through chemical change: sodium chloride
Chemical Symbols • Each element has a symbol for its atom: H-Hydrogen Na-Sodium N-Nitrogen Ca-Calcium O-Oxygen Cl-Chlorine
Laws of Chemical Changes • Conservation of MASS 2A + 2B 2AB Mass before = Mass after (reactants) (products) • Definite Proportion: in compound AB, Mass of A Mass of B Constant
What is MATTER Made of ? small particles ATOMS
Dalton’s Atomic Theory • MATTER consists of tiny particles called Atoms • Atoms are indestructible • Atoms of one element has identical MASS and other properties • Atoms of different elements has different mass and properties • Atoms can form compounds in a fixed numerical ratio
+ Atomic Aspects of Chemical Reactions • Chemical reaction is a process which atoms separate or unite, no atoms are destroyed or created • 2A + 2B 2AB • Atomic ratio: A:B=1:1 • Mass ratio: mA:mB = Constant
Law of Multiple Proportions • Element A and B can form two or more kinds compounds: e.g. AB, or AB2, AB3 • A + BAB • A + 2BAB2 • A + 3BAB3 • For the same amount of A, the mass of B in the three compounds would be: 1:2:3
Physical States of Water wps.prenhall.com/.../165/169061/blb9ch0102.html
Multiple Proportions sulfur sulfur dioxide trioxide Mass S 32.06 g 32.06 g Mass O 32.00 g 48.00 g
Review questions • Identify physical change vs. chemical change: ice melts, coal burns • Identify chemical property vs. physical property, grass is green, grass burned to ash • How small are atoms compare to your computer? • How many elements are in nature?