Chemistry: Spring Semester Lecture Notes



Honors Chemistry Name:______________________________Unit 1: Introduction to ChemistryInternet web site: 584581091440Safety Basic Safety Rules#1 Rule:Others:Safety Features of the LabMaterial Safety Data Sheet (MSDS) -- -- lists Dos, Don’ts, and emergency proceduresChemical Exposureacute exposurevs.chronic exposuree.g.,e.g.,LD50: the lethal dosage for 50% of the animals on which the chemical is tested5651500129062Example: Chemical A: LD50 = 3.2 mg/kgChemical B: LD50 = 48 mg/kgWhich is more toxic?Science The Functions of Sciencepure scienceapplied sciencee.g., aluminume.g.,Science attempts to…risk-benefit analysis: How does scientific knowledge advance?1. 3. 2. 4. The Scientific Method** Key: observation inferenceTypes of Dataqualitative dataquantitative data---- e.g., e.g., Parts of the Scientific MethodIdentify something you don’t know.Make a hypothesis: Experiment to test hypothesis. procedure: the order of events in an experimentvariable: Experiments must be controlled.conclusion: 5486400-211455Scientific Law vs. Scientific Theorylaw: -- Laws are often written in the form of…-- e.g., 530860092075theory: -- -- e.g., Phlogiston Theory of Burning1. Flammable materials contain phlogiston.2. During burning, phlogiston is released into the air.3. Burning stops when………4114800184785 Chemistry The Beginningearly practical chemistry: 4800600285753200400142875 4572000-3175285750089535The Greeks believed there were four elements.6057900144780Alchemy (~500 – 1300 A.D.)the quest for the Philosopher’s Stone....... ...Alchemical symbols for substances…transmutation: In ordinary chemical reactions… Contributions of alchemists:502412086995What is chemistry?Areas of Chemistry organic: the study of ______-containing compounds inorganic: studies everything except ______ (e.g., compounds containing ______) biochemistry: the chemistry of… physical: measuring physical properties of substancese.g., 814070194945Careers in Chemistryresearchproduction development chemical salessoftware engineeringteachingThe skills you will develop by an earnest study of chemistry will help you in any career field.4800600-342900The Scope of Chemistrybulk chemical manufacturingpharmaceuticalspetroleum productssynthetic fibersChemistry impacts: -- --Government Regulation of Chemicals The various levels of government regulate chemicals to protect the:environment consumerworker2286000217170011430046863000# OFSTUDENTSABCDFCHEMISTRY GRADES Manipulating Numerical Data GraphsBar graph: % OF STUDENTS INEACH GRADEAT NCHS10th 26%9th30% 11th 23%12th21%Pie graph:YEARCOST OFCONCERTTICKET ($)COST OF CONCERT TICKET OVER TIMELine graph: ** In chemistry…Elements of a “good” line graph:1.3. 2.4. Essential Math of ChemistryScientific Notation -- used to express very large or very small numbers, and/or to indicate precision. Also can be used to maintain correct sig figs.Form: 800 = 2531 = 0.0014 = EX.Put in standard form.1.87 x 10–5 = 7.88 x 101 = 3.7 x 108 = 2.164 x 10–2 =EX.Change to scientific notation.12,340 = 0.008 = 0.369 =1,000,000,000 =Using the Exponent KeyThe EE or EXP or E key means “times 10 to the…”??????yx??????X??yxnot… or…??????X??????????How to type out 6.02 x 1023: and not… Also, know when to hit your (–) sign.1.2 x 105 2.8 x 1019 = ????????????EX.7.5 x 10–6 (–8.7 x 10–14) = 5.76 x 10–16 9.86 x 10–4 = 4.35 x 106 (1.23 x 10–3) = 8.8 x 1011 x 3.3 x 1011 =Accuracy and PrecisionAll numerical data are the result of uncertain measurements. precision: a measure of the degree of fineness of a measurement; it depends on the extent to which the instrument is calibratede.g., When repeated, precise measurements yield similar answers each time.e.g., precise…imprecise…4714240-147955accuracy: Three types of error can affect accuracy.human error: -- minimize with repeated measurements method error: e.g., parallax in measuring with a meter stickinstrument error: e.g., bathroom scale that reads 5 lbs. too heavySignificant Figures (SF)A student is combining separate water samples, all of differing volumes, into one large bucket. Samples A, B and C are 25 mL, 16.37 mL and 50 mL, respectively. Once combined, what is the total volume of all the samples? Measurement and PrecisionA (25 mL)B (16.37 mL)C (50 mL)Identifying a number as a SFCounting SF’s in a numberNon-zero numbers:ZeroesLeft:Middle:Right:w/ decimal point:w/o decimal point:Exact NumbersCountsConstantsConversion FactorsHow many SF?25 g0.12 kg0.030 kg1240560. cm1.240560 x 106 mg6000000 kg6 x 104 sec6.00 x 106 kg246.31 g409 cm20.06 cm29.200 dm1.050 m0.02500 g Sig Figs with calculationsNote:Addition/Subtraction11.31 + 33.264 + 4.1 =Multiplication/Division5.282 x 3.42 = Back to the original question… A student is combining separate water samples, all of differing volumes, into one large bucket. Samples A, B and C are 25 mL, 16.37 mL and 50 mL, respectively. Once combined, what is the total volume of all the samples? EX.Round each to the correct number of significant figures.Calculator says…2 sig. figs.3 sig. figs.5 sig. figs.75.60.52839638760042008.4845E–4Mathematics ReviewUnits must be carried into theanswer, unless they cancel. Solve for x.SI Prefixeskilo-(k)centi-(c)deci-(d)milli-(m)Also, 1 mL = 1 cm3 and 1 L = 1 dm3Conversion Factors and Unit CancellationEX. How many cm are in 1.32 meters?equality: conversion factors: EX. How many m is 8.72 cm?EX. How many kilometers is 15,000 decimeters?EX. How many seconds are in 4.38 days?Simple Math with Conversion Factors EX.For the rectangular solid: L = 14.2 cmW = 8.6 cmH = 21.5 cmFind volume.Convert to mm3. mm and cm differ by a factor of……..mm2 “ cm2 “ “ “ “ “ ……..mm3 “ cm3 “ “ “ “ “ …….. Basic Concepts in Chemistry chemical: chemical reaction: a rearrangement of atoms such that…“what you end up with” differs from “what you started with”methane + oxygen sodium + water Law of Conservation of Mass: synthesis: putting simpler substances together, usually inmany steps, to make something more complex ................
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