Chemistry: Unit 1



Unit 1: Introduction to ChemistryInternet web site: christjs/3660775190500 Safety #1 Rule:Use common sense.Others:No horseplay.No unauthorized experiments.Handle chemicals/glassware with respect.Safety Features of the Labshowerfire blanketfire extinguishereye washfume hoodcircuit breaker switchMaterial Safety Data Sheet (MSDS) -- gives info about a chemical. -- lists Dos and Don’ts; emergency proceduresChemical Exposureacute exposurevs.chronic exposuredamage occurs after damage occurs after a one-time event long-term, repeated exposuree.g.,reaction to drugse.g.,smoking;or medicationasbestos3546475222885LD50: lethal dosage for 50%of creatures that the chemical is tested onExample: Chemical A: LD50 = 3.2 mg/kgChemical B: LD50 = 48 mg/kgChemical A is more toxic; it takes less to inflict damage. Science The Functions of Sciencepure sciencevs.applied sciencethe search for knowledge;using knowledge in a factspractical way33166051708154800600183515e.g., aluminum354330089535stronglightweightgood conductorScience attempts to establish cause-effect relationships.risk-benefit analysis: weigh pros and cons before decidingHow does scientific knowledge advance?1. curiosity2. good observations3. determination4. persistence35433000The Scientific Method** Key: Be a good observer. **1. Identify an unknown.2. Make a hypothesis: a reasonable explanation-- must be testable3. Repeatedly experiment to test hypothesis. procedure: order of events in experimentvariable: any factor that could influence the resultExperiment must be controlled: Must have two set-ups that differ by only one variable.observationvs. inferencewhat you sense involves a judgment or measureTypes of Dataqualitative dataquantitative data-- descriptions-- measurements-- e.g., clear liquid-- 55 L or 83oCconclusion: must be based on dataLaw vs. Theorylaw: states what happens-- do not change-- never violated-- e.g., law of gravity, laws of conservationtheory: tries to explain why or how something happens400431066040-- based on current evidence-- e.g., theory of gravity, atomic theoryPhlogiston Theory of Burning1. Flammable things contain phlogiston.2. During burning, phlogiston is released into air.3. Burning stops when……object has released all its phlogiston, or…surrounding air contains too much phlogiston.(superceded by combustion theory of burning) Chemistry The Beginning4133850371475early practical chemistry-- household goods45897801428753074035301625-- weapons-- soap-- wine2175510381635-- basic medicine4000500278765The GreeksGreeks believed in four elements.?? earthwind firewater1257300342900Alchemy (~500 – 1300 A.D.)the quest for the Philosopher’s StoneIt was supposed to change cheap metals into gold.. . . . . . . . . . . .. . .Alchemical symbols for substances…SAND IRONCOPPERSILVERGOLDtransmutation: changing one substance into anotherIn ordinary chemistry, we cannot transmute elements. Contributions of alchemists:lab apparatus / procedureshow to make some alloysproperties of some elements947420-42545chemistry: the study of matterand its changesAreas of Chemistryorganic: the study of carbon-containing compoundsinorganic: studies everything except carbon (e.g., metals)biochemistry: the chemistry of living thingsphysical: measuring physical properties of substances486410375920Careers in Chemistryresearch (new products)production (quality control)development (scale up manufacturing processes)chemical salessoftware engineeringteachingThe skills you will develop by an earnest study of chemistry will help you in any career field.3657600102870The Scope of Chemistry-- petroleum products-- synthetic fibers-- pharmaceuticals-- bulk chemical manufacturing#1 chemical = sulfuric acid (H2SO4)All fields of endeavor are affected by ernment Regulation of Chemicals…to protect the…4717415360680environment consumerworker205740080645013970EPAConsumer Product OSHA Safety Commission, USDA, BATF, FDA Manipulating Numerical Data # OFSTUDENTSABCDFCHEMISTRY GRADEDISTRIBUTION,FALL SEMESTERGraphsBar graph: shows how manyof something arein each category% OF STUDENTS INEACH GRADEAT NCHS10th26%9th30%11th23%12th21%Pie graph:shows how a wholeis broken into partsYEARCOST OFCONCERTTICKET ($)COST OF CONCERT TICKET OVER TIMELine graph: shows continuouschange** In chemistry, always use a line graph.Elements of a “good” line graph:1. axes labeled, w/units3. use available space2. title4. neatScientific Notation-- used for very large or very small numbers, and/orto indicate precisionForm:(# from 1 to 9.9) x 10exponentExamples:800 = 8 x 10 x 10 = 8 x 1022531 = 2.531 x 10 x 10 x 10 = 2.531 x 1030.0014 = 1.4 10 10 10 = 1.4 x 10–3Put in standard form.1.87 x 10–5 = 0.00001873.7 x 108 = 370,000,0007.88 x 101 = 78.82.164 x 10–2 = 0.02164Change to scientific notation.12,340 = 1.234 x 1041.234 40.369 = 3.69 x 10–10.008 = 8 x 10–310,000,000 = 1 x 107Essential Math of ChemistryUnits must be carried into answer, unless they cancel. Solve for x. SI Prefixeskilo-(k)1000centi-(c)1/100milli-(m)1/1000deci-(d)1/10Also, 1 mL = 1 cm3 and 1 L = 1 dm3Conversion Factors and Unit Cancellation1. How many cm are in 1.32 meters?equality (equivalence statement): 1 m = 100 cmconversion factors:1 mor100 cm 100 cm 1 m2. How many m is 8.72 cm?3. How many kilometers is 15,000 decimeters?4. How many seconds are in 4.38 days?9.1 cm4.6 cmSimple Math with Conversion FactorsFind area of rectangle.A = L x W = 9.1 cm (4.6 cm) = 42 cm2Convert to m2.** Convert to mm2.For the rectangular solid: L = 14.2 cmW = 8.6 cmH = 21.5 cmFind volume.V = L W H = 14.2 cm(8.6 cm)(21.5 cm) = 2.6 x 103 cm3Convert to mm3. mm and cm differ by a factor of……..10mm2 “ cm2 “ “ “ “ “ ……..100mm3 “ cm3 “ “ “ “ “ ……..1000Using the Exponent KeyThe EE or EXP or E key means “times 10 to the…”???????How to type 6.02 x 1023:???????????not…????????or…and not…????????????Also, know when to hit your (–) sign.?????????????1.2 x 105 2.8 x 1019 = 4.3 x 10–157.5 x 10–6 (–8.7 x 10–14) = –6.5 x 10–94.35 x 106 (1.23 x 10–3) = 5.35 x 103 or 5350.55.76 x 10–16 9.86 x 10–4 = 5.84 x 10–138.8 x 1011 x 3.3 x 1011 = 2.9 x 1023 Basic Concepts in Chemistry chemical: any substance that takes part in, or occurs asa result of, a chemical reactionchemical reaction: a rearrangement of atoms such that “what you end with” differs from “what you start with”productsreactantsmethane + oxygen carbon dioxide + water CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)sodium + water hydrogen + sodium hydroxide 2 Na(s) + 2 H2O(l) H2(g) + 2 NaOH(aq)Law of Conservation of Mass: total mass of products = total mass of reactantsPmass = RmassNothing is created or destroyed.synthesis: putting small molecules together, usually inmany steps, to make something more complex ................
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