UNIT ONE – CHAPTER ONE MATTER AND CHANGE

CHEMISTRY Chemistry The study of the composition of substances and the changes they undergo. 5 major divisions 1. Organic chemistry: study of all substances that contain carbon. 2. Inorganic chemistry: substances sans carbon. 3. Analytical: composition of substances 4. Physical: concerned with theories and experiments that describe chemicals 5. Biochemistry: study of chemistry of living organisms

LAB TOOLS

OBSERVATIONS & INFERENCES (INTERPRETATIONS) OBSERVATION: Making a determination using 1 or more of your 5 senses Which senses are NOT used in the chemistry lab?

OBSERVATIONS & INFERENCES (INTERPRETATIONS) INFERENCE/INTERPRETATION: A determination based on prior knowledge (educated guess)

LET’S PRACTICE  The sky is really cloudy.  A storm is coming.  The candle is made of wax.  The pan is hot.  Ice freezes at 0◦ C  Sugar is sweet.  The pan is getting ready to boil over.

MATTER Matter: Anything that takes of space and has mass. A golf ball has more matter that a tennis ball. Mass: The amount of matter an object contains Substance: a particular kind of matter that has form and definite composition.

Properties of Matter Physical Property: a quality or condition of substance that can observed or measured without changing the composition of the substance.

Properties of Matter Physical Properties  Extensive: depends on the amount of substance present-example: mass, length, volume  Intensive: independent of the amount of substance present. Examples: color, crystal shape, density, melting and boiling points, ductility, malleability, conductivity.

Chemical Properties Chemical properties-depend on the action of a substance when in the presence of other substances. Does it: burn Help others burn? React with H 2 O ? Is it toxic? What else will it react with?

States of Matter Solid  Has a definite shape  Has a definite volume  Particles are packed closely together  Cannot easily be compressed

States of Matter Liquid  Flows easily  Has a definite volume  Indefinite shape – takes on shape of container  Somewhat tightly packed – not easily compressed

States of Matter Gas  Indefinite Shape-Takes on shape of container  Indefinite volume-Takes on volume of container  Lots of space between particles- easily compressed

States of Matter Vapor  Not the same thing as a gas!  Means the gas phase of a substance that is normally a liquid or solid at room temperature  Gaseous water is a vapor  Oxygen is a gas

Changes of Matter Physical Changes  Alters a physical property of a substance  Composition of the substance remains the same  Examples:-boiling, freezing, dissolving, breaking crushing, etc.

Changes of Matter Chemical Changes or Rxns  Alters the chemical composition of the substance  After the change, you do not have the same substance that you started with  Examples-burning paper, cooking an egg, etc.

TYPES OF MIXTURES 2 types of mixtures: Homogeneous (solutions) the components that make up the mixture are uniformly distributed throughout the mixture. Salt water Simple syrup Kool-Aid

TYPES OF MIXTURES Heterogeneous: the components of the mixture are not uniform or have localized regions with different properties. Granite Sand Stew

SolventSoluteExample MediumDispersedColloids (fine dispersions) Suspensions(coarse dispersions) Gas AirGasliquidFog, mist, smoke, hair spray LiquidGasDO/H 2 OGasSolidAerosols, smoke, cloud, air particulates smokecloud particulates Solid Bronze (Alloy)LiquidGasLiquid foam: whipped cream, shaving creamfoam whipped cream shaving cream Liquid Emulsion: milk, mayonnaise, hand creammilk mayonnaisehand cream Liquid Alcoholic beverages LiquidSolidpigmented inkpigmented ink, bloodblood mudmud (soil, clay or silt particles are suspended in water), chalk powder suspended in watersoilclaysilt chalk SolidLiquidSalt waterSolidGasSolid foam: aerogel, styrofoam, pumice aerogel styrofoam pumice Foam: dry spongesponge solidLiquidAmalgam(mercury In gold or silver) SolidLiquidGelGel: agar, gelatin, silicagel, opalagar gelatin silicagelopal Wet sponge Solid cranberry glass ClayClay, Silt, Sand, Gravel, GraniteSiltSand GravelGranite

Chemical Symbols Most come from the first letter or two in the name of the element First letter capitalized, following ones are lower case Some come from the element name in a different language, usually Greek or Latin Some come from the abbreviation of the name of a scientist Shorthand way to write the element

Chemical Symbols Rules If the symbol consists of letter, it must be an upper case. If the symbol consists of 2 letters, it must be an upper case with a lower case

Chemical Reactions  One or more substance turn into a new substance  Reactants-starting substances  Products-ending substances  Reactants → Products Reactant + Reactant → Product + Product

Law of Conservation of Mass/Matter  States: In any chemical or physical reaction, mass/matter can neither be created nor destroyed only transferred.  In other words, the mass of the reactants must equal the mass of the products.

MASS VS WEIGHT MASS: The amount of matter an object contains WEIGHT: the affect that gravity has on a substance.

MASS VS WEIGHT

SCIENTIFIC METHOD 1.State the problem 2.Observations 3. Hypothesis 3.Data Gathering/Experiment 4.Conclusion 5. Theory 6.Scientific Law

ACCURACY & PRECISION Accuracy refers to the closeness of a measured value to a standard or known value Precision refers to the closeness of two or more measurements to each other.