chemistry notes : chapter 1

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<ul><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 1/10</p><p>Matter,Measurement andCalculations</p><p>Chemistry and the Scientific MethodMatter, Properties and Changes</p><p>Classification of MatterMeasurement and UnitsAccuracy and Precision</p><p>Significant FiguresExamples of Units in Calculations</p><p>ajor divisions</p><p>Biochemistry Study of biological chemicals</p><p>Organic Carbon based compounds</p><p>Inorganic All other elements</p><p>Analytical Methods of analysis</p><p>Physical Theory and concepts</p><p>Scientific methodAll scientific studies follow the same approach toexamining a problem.</p><p>The scientific method requires that we -</p><p>Apply logical, organized reasoningto any observations made.</p><p> Form a hypothesis.</p><p>Reject or confirm that hypothesis</p><p>through experiments.</p><p>Scientific method</p><p> Observation</p><p>Descriptions and measurements.</p><p> Pattern Recognition</p><p>Cause and effect of relationships &amp; trends. </p><p> Develop</p><p>Make hypothesis and then test it.</p><p> Experimentation</p><p>Create and use tests to prove or disprove yourhypothesis leading to atheory.</p><p>Yes</p><p>No</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 2/10</p><p>Chemical properties</p><p>Wood+O2D</p><p>CO2+H2O+ heat</p><p>Ma ter</p><p>Pure Substance Mix ure</p><p>Element(Iron)</p><p>Compound(Hemoglobin)</p><p>Homogeneous(Plasma)</p><p>Heterogeneou(Blood)</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 3/10</p><p>Formula BP (oC)</p><p>Density(g/L)</p><p>Other</p><p>Hydrogen H2 -253 0.90 Flammable</p><p>Oxygen O2 -218 1.14Supports</p><p>combustion</p><p>Water H2O 100 1000 Not flammable</p><p>Question Does eating junkweight gain?</p><p>food cause</p><p>ExperimentMeasure weight,</p><p>week and see w</p><p>pig out for a</p><p>at happens.</p><p>DataInitial weight</p><p>119 lb</p><p>Final weight</p><p>125 lb</p><p>Gain = final weight - initial weig</p><p>Gain = 125 lb - 119 lb = 6 lbs</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 4/10</p><p>Measurement in chemistry</p><p>1 barrel = 42 gallons</p><p>1 gallon = 4 quarts</p><p>1 quart = 4 cups</p><p>1cup = 16 tablespoons</p><p>1 tablespoon = 3 teaspoons</p><p>How many teaspoons of oil are in a barrel?</p><p>1bbl# 42bblgal# 4</p><p>galqt# 4</p><p>qtcup# 16</p><p>cuptbl# 3</p><p>tbltsp</p><p>= 32 256 tsp</p><p>Metric unitsOne base forYou then use</p><p>each type of mrefixes to cha</p><p>easurement.ge size.</p><p>Some com on base units</p><p>Type Name Symbol</p><p>Mass gram g</p><p>Length meter m</p><p>Volume liter l</p><p>Time second s</p><p>Energy joule j</p><p>Prefix Symbol Factor</p><p>giga G 10 9 1 000 000 000</p><p>mega M 10 6 1 000 000</p><p>kilo k 10 3 1 000</p><p>---- 10 0 1</p><p>deci d 10 -1 0.1</p><p>centi c 10 -2 0.01</p><p>milli m 10 -3 0.001</p><p>micro 10 -6 0.000 001</p><p>nano n 10 -9 0.000 000 001</p><p>pico p 10 -12 0.000 000 000 001</p><p>We change the prefix to alter the size of the unit. How may milligrams (mg) are in a kilogram (kg)?</p><p>1 kg = 1000 g</p><p>1 g = 1000 mg</p><p>answer= 1kg : 1000 kgg</p><p>: 1000 gmg</p><p>answer= 1000 000mg</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 5/10</p><p>SI - System InternationalSystem International</p><p>Systematic subset of the metric system.</p><p>Only uses certain metric units.</p><p>Mass kilograms</p><p>Length meters</p><p>Time seconds</p><p>Temperature kelvin</p><p>Amount mole</p><p>Other SI units are derived from base SI units.</p><p>Factor label method</p><p>Regardless of the type of calculation,keeping track of the units makes thingcome out right.</p><p>Must use conversion factors - relationshipbetween two units</p><p>Canceling out units is a way of checkingthat your formula is set up right!</p><p>English FactorFactor</p><p>1 gallon = 4 quarts 4 qt/gal</p><p>1 mile = 5280 feet 5280 ft/mile</p><p>1 ton = 2000 pounds 2000 lb/ton</p><p>Common English to Metric conversions</p><p> FactorFactor</p><p>1 liter = 1.057 quarts 1.057 qt/l</p><p>1 kilogram = 2.2 pounds 2.2 lb/kg</p><p>1 meter = 1.094 yards 1.094 yd/m1 inch = 2.54 cm 2.54 cm/inch</p><p>A nerve impulse in the body can travel as fast as400 feet/second.</p><p>What is its speed in meters/min ?</p><p>Conversions Needed</p><p>1 meter = 3.3 feet</p><p>1 minute = 60 seconds</p><p>m 400 ft 1 m 60 sec</p><p>min 1 sec 3.3 ft 1 min</p><p>m 400 ft 1 m 60 sec</p><p>min 1 sec 3.3 ft 1 min?? = x x</p><p>?? = x x</p><p>m</p><p>min....Fast7273</p><p>All measurements contain some uncertainty.</p><p>We make errors</p><p> Tools have limits</p><p>Uncertainty is measured using</p><p>Accuracy How close to the true value</p><p>Precision How close to each other</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 6/10</p><p>Accuracy</p><p>How close ourvalues agree withthe true value.</p><p>Here, the averagewould be close tothe true answerbut the numbersdo not agree.</p><p>Large randomerror.</p><p>Precisio</p><p>How close ourvalues agree witheach other.</p><p>Here, they are allclose to eachother but notclose to the truevalue.</p><p>Large systematicerror.</p><p>Accuracy and precision</p><p>Our goal!</p><p>Good precisionAND goodaccuracy.</p><p>These are values</p><p>we can trust.</p><p>Predict the effect on accuracy and precision.</p><p>Instrument not zeroed properly</p><p>Reagents made at wrong concentration</p><p>Temperature in room varies wildly</p><p>Lab partner is not properly trained</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 7/10</p><p>0 1 2 3 4 5</p><p>Method used to express accuracy &amp; precision.</p><p>You cant report numbers better than the methodused to measure them.</p><p>67.2 units = three significant figures</p><p>CertainDigits</p><p>UncertainDigit</p><p>These numbersall have three</p><p>significant figures!</p><p>Leading zeros are notare not significant.</p><p>0.421 - three significant figuresLeading zeroLeading zero</p><p>Captive zeros areare significant.4012 - four significant figures</p><p>Trailing zeros areare significant.114.20 - five significant figures</p><p>Captive zeroCaptive zero</p><p>Trailing zeroTrailing zero</p><p>0.00321321 = 3.213.21 x 10-</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 8/10</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 9/10</p><p>The Celsius scale isbased on themelting point (0 oC)and boiling point(100 oC) of water.</p><p>Example. oF to oC</p><p>If it is 20 oF outside, what is it in oC ?</p><p>oC = (oF - 32)5</p><p>9</p><p>oC = (20 oF - 32)5</p><p>9</p><p>oC = -6.7 (two significantfigure in 20 oF)</p></li><li><p>7/27/2019 chemistry notes : chapter 1</p><p> 10/10</p><p>HydrometerHydrometer</p><p>Float height willbe based onSpecific Gravity.</p></li></ul>