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ChemistryDiscover Science

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Discover Science: ChemistryTextbook

Philippine Copyright 2012 by DIWA LEARNING SYSTEMS INCAll rights reserved. Printed in the Philippines

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ISBN 978-971-46-0289-2

AuthorsDino F. de Guzman earned his master’s degree in chemical education from the University of the Philippines–Manila. He obtained his bachelor’s degree in biochemistry and post-baccalaureate degree in teaching education from the University of the Philippines–Diliman. Mr. de Guzman is a licensed teacher and has taught science in Claret School, James K International Education Center, and La Salle Green Hills. He was also a college lecturer at Polytechnic University of the Philippines. Maria Elena G. Delos Reyes obtained her diploma in science education from Philippine Normal University and her cognate in education and bachelor’s degree in chemistry, with distinction, from St. Scholastica’s College. She is also a licensed professional teacher and a member of the Association of Science Teachers and Educators of the Philippines and of the Philippine Association of Chemistry Teachers. Ms. Delos Reyes has taught science and health in grades 3 to 6 at St. Anthony School. In high school, she taught integrated science, chemistry, and physics at Cavite School of St. Mark, St. Anthony School, and St. Scholastica’s College–Manila. At present, she works as a home-based writer, editor, and transcriptionist. Allen A. Espinosa is currently completing his thesis requirements for his master’s degree in chemistry education at the University of the Philippines–Diliman. He obtained his bachelor’s degree in secondary education major in chemistry, cum laude, from Philippine Normal University. Mr. Espinosa has taught chemistry at La Salle Green Hills, chemistry and integrated science at Philippine Institute of Quezon City, and chemistry and physics at Saint Pedro Poveda College. At present, he teaches at Colegio de San Juan de Letran and at De La Salle College of Saint Benilde. Mr. Espinosa is a member of the Philippine Association of Chemistry Teachers.

ConsultantClaribelle J. Bautista finished her doctorate in philosophy in education and her master’s degree in teaching major in chemistry from the University of the Philippines–Diliman. She earned her bachelor’s degree in education major in chemistry from Mindanao State University. Dr. Bautista is a licensed teacher and taught mostly chemistry at the high school department of Lourdes School of Mandaluyong, where she also served as a science coordinator and an assistant principal on academics. She is the founding president of the Science Educators Association of Mandaluyong.

Preface

The 21st century is marked by numerous advancements in science and technology. With all these advancements, it is necessary that you are equipped with the basic science and technological skills. This book, Discover Science: Chemistry, is designed to help you acquire the skills you need in the 21st century. As you read through the lessons and perform the given activities in this book, you will develop your inventive thinking skills; global awareness; and personal, social, and civic responsibility, among others.

This book, which has been carefully designed to better facilitate your learning, is composed of the following components:

Word Up includes an activity (e.g., word maze, crossword puzzle, etc.) that introduces the important terms you will encounter in the lesson.

Sci-Kick displays a comic strip of two characters named Isay and Kiko. These characters will tap your imagination on how the science concept(s) to be learned is evident in real life.

CSI (Cool Science Investigation)/Try It Out! presents an experiment/exercise that allows you apply the science concept(s) you have learned in the lesson.

Chapter Test includes a 15-item multiple-choice exercise that measures your understanding of the science concepts discussed in a chapter.

Science Cares presents an activity that relates the science concepts you have learned in a chapter to different issues concerning the environment and the society. This will make you realize how your knowledge in science can help you become a better citizen.

Performance Tasks lists tasks that will allow you to apply what you have learned to various fields of discipline.

IP Checkup monitors the progress of your investigatory project (IP) at the end of each unit. A chapter in this book has been solely allocated for you to learn how to construct an investigatory project.

Aside from the components given above, some lessons in this book include the following additional sections:

Pinoy Science gives an example of a notable Filipino and his or her remarkable contributions to science and technology.

Info Overload presents a science trivia related to the science concept discussed in the lesson.

May this book help you understand and appreciate chemistry better. Remember that most scientific discoveries sprouted from a simple question or a little dose of curiosity. Keep on learning and enjoying as you discover the nature of chemistry!

Unit I The Building Block of ScienceChapter 1 Nature of Chemistry .......................................................................................... 2Lesson 1 The Evolution of Chemistry .................................................................................................2 2 Chemistry: Its Role in Science, Technology, and Society ...................................................6 3 The Processes, Tools, and Techniques in Chemistry .........................................................14Chapter Test .........................................................................................................................................30Science Cares .......................................................................................................................................32Performance Tasks ...............................................................................................................................32

Chapter 2 Measurement .................................................................................................... 33Lesson 1 Importance of Measurement ..............................................................................................33 2 Significant Figures .............................................................................................................39 3 Scientific Notation..............................................................................................................44 4 Mass, Volume, Density, and Temperature ..........................................................................48Chapter Test ..........................................................................................................................................54Science Cares ........................................................................................................................................55Performance Tasks ................................................................................................................................55

Chapter 3 The Methods of Science ................................................................................... 56Lesson 1 The Scientific Process ........................................................................................................56 2 Investigatory Science Project .............................................................................................60Chapter Test ..........................................................................................................................................71Science Cares ........................................................................................................................................73Performance Tasks ................................................................................................................................73

Chapter 4 Matter ................................................................................................................ 74Lesson 1 The Nature of Matter..........................................................................................................74 2 Classification of Matter ......................................................................................................79Chapter Test ..........................................................................................................................................89Science Cares ........................................................................................................................................91Performance Tasks ................................................................................................................................91

Chapter 5 Understanding the Atom ................................................................................. 92Lesson 1 The Road to Atomic Theory ...............................................................................................92 2 Atoms, Isotopes, and Ions ................................................................................................101Chapter Test ........................................................................................................................................108Science Cares ......................................................................................................................................109Performance Tasks ..............................................................................................................................109IP Checkup ..........................................................................................................................................110

Table of Contents

Unit II The World of ChemicalsChapter 6 The Periodic Table ......................................................................................... 114Lesson 1 The Development of the Periodic Table ...........................................................................114 2 Electron Configuration .....................................................................................................121 3 Groups and Periods in the Periodic Table ........................................................................134Chapter Test ........................................................................................................................................143Science Cares ......................................................................................................................................144Performance Tasks ..............................................................................................................................144

Chapter 7 Chemical Bonding ............................................................................................ 145Lesson 1 Bond Formation and Molecular Geometry ......................................................................145 2 Molecular Geometry ........................................................................................................157 3 Chemical Nomenclature ...................................................................................................165Chapter Test ........................................................................................................................................169Science Cares ......................................................................................................................................170Performance Tasks ..............................................................................................................................170

Chapter 8 Chemical Reactions ......................................................................................... 171Lesson 1 Chemical Equations .........................................................................................................171 2 Stoichiometry and Other Calculations .............................................................................181Chapter Test ........................................................................................................................................194Science Cares ......................................................................................................................................195Performance Tasks ..............................................................................................................................196IP Checkup ..........................................................................................................................................196

Unit III Gas, Solid, and LiquidChapter 9 Gases ................................................................................................................. 200Lesson 1 Properties of Gases...........................................................................................................200 2 Gas Laws ..........................................................................................................................205Chapter Test ........................................................................................................................................219Science Cares ......................................................................................................................................221Performance Tasks ..............................................................................................................................221

Chapter 10 Solids and Liquids .......................................................................................... 222Lesson 1 Nature of Solids and Liquids ...........................................................................................222Lesson 2 Phase Change ...................................................................................................................229Chapter Test ........................................................................................................................................233Science Cares ......................................................................................................................................235Performance Tasks ..............................................................................................................................235

Chapter 11 Gases, Solids, and Liquids in Mixtures ........................................................ 236Lesson 1 Nature of Solutions ..........................................................................................................236 2 Colloids ............................................................................................................................247Chapter Test ........................................................................................................................................255

Science Cares ......................................................................................................................................257Performance Tasks ..............................................................................................................................257

Chapter 12 Aqueous Solutions .......................................................................................... 258Lesson 1 Oxidation-Reduction Reactions .......................................................................................258 2 Acid-Base Reactions ........................................................................................................269Chapter Test ........................................................................................................................................282Science Cares ......................................................................................................................................283Performance Tasks ..............................................................................................................................283IP Checkup ..........................................................................................................................................284

Unit IV Applications of ChemistryChapter 13 Introduction to Nuclear Chemistry .............................................................. 286Lesson 1 Radioactivity ....................................................................................................................286 2 Nuclear Transformation ...................................................................................................297Chapter Test ........................................................................................................................................300Science Cares ......................................................................................................................................302Performance Tasks ..............................................................................................................................302

Chapter 14 Introduction to Organic Chemistry ............................................................. 303Lesson 1 Nature of Organic Compounds ........................................................................................303 2 Hydrocarbon Derivatives .................................................................................................314Chapter Test ........................................................................................................................................321Science Cares ......................................................................................................................................323Performance Tasks ..............................................................................................................................323

Chapter 15 Introduction to Biochemistry ........................................................................ 324Lesson 1 Biomolecules ....................................................................................................................324 2 Metabolism.......................................................................................................................337Chapter Test ........................................................................................................................................339Science Cares ......................................................................................................................................341Performance Tasks ..............................................................................................................................341

Chapter 16 Chemistry in Daily Life ................................................................................. 342Lesson 1 Food Chemistry ................................................................................................................342 2 Industrial Chemistry .........................................................................................................347Chapter Test ........................................................................................................................................351Science Cares ......................................................................................................................................352Performance Tasks ..............................................................................................................................353IP Checkup ..........................................................................................................................................353

Glossary ..........................................................................................................................................355Bibliography .......................................................................................................................................357Index ..........................................................................................................................................359

IUNITThe Building

Block of Science

H ave you ever wondered what makes up the things that you use every day such as your clothes, perfume, lotion, pens, and books? Do you want to know how fuel makes power plants and cars run? Do you want to investigate how medicines, ice cream, and sandwich spread are made? Do you want to know what makes up paint, insecticides, air fresheners, and fertilizers? Perhaps, you are fascinated with the advanced technologies used in forensics, medicine, research, sports, and communication. All of these involve chemistry—the building block of science. This unit invites you to take a look at and experience the wonderful world of chemistry. You will discover how chemistry began and developed to improve the quality of people’s lives. You will learn why chemistry can be considered the building block of all sciences, including biology, physics, and geology. You will be trained to work like a real scientist. You will realize the significance of the development of atomic theory to the technology you enjoy today.

Discover Science: Chemistry�

Sci-kick

In this chapter, you will be able to• trace the historical development of chemistry;• recognize significant contributions of some Filipino and foreign chemists;• explain how chemistry influences science, technology, and society;• explain the nature of different types of matter;• practice safety precautions in using different laboratory apparatus during experiments;• apply rules of significant figures in solving measurement problems;• plan an investigatory project that entails precise and accurate gathering of data; and

• appreciate the importance of chemistry in daily life.

Chapter 1

Nature of Chemistry

Lesson 1 The Evolution of Chemistry

Fillinthemissingletterstofindthetermthateachstatementdescribes.

1. P__________A–Itistheappropriatecombinationofingredientsthatwouldcurealldiseases.2. A__________Y–Itisapredecessorofchemistry.3. E________RofL____E–Itisasubstancethoughttobringimmortality.4. M______________M–Itisabeliefincommunicationandunionwithadivinebeing.5. C________________N–Itisaprocessinwhichfuelreactswithoxygentoproduceheat, light,andflame.

Word Up

I guess you’re right! And chemistry is one of the reasons why technological advances continue.

Do you have any idea why we live in a modern world today? I think it’s because

of the advancement of technology.

The Building Block of Science �

Chemistrycanbetracedbacktoasfarastheprehistorictimes.Itshistoryanddevelopmentcanbedividedintofourperiods:blackmagic,alchemy,traditionalchemistry,andmodernchemistry.

Black Magic TheperiodofblackmagiccoverstheprehistorictimesuntilthebeginningoftheChristianera.Theancientpeoplelivedinaroughenvironmentwheretheyneededtoprotectthemselvesandtofindwaysofprocuringtheirsustenance.Theytriedtosurvivebyusingwhattheyknew.Theydiscoveredhowtolightafireevenwithoutknowingthechemicalprincipleinvolvedinit.Thediscoveryoffiresignificantlyshapedtheearlypeople’scuriosityincontrollingchemicalchanges.Peoplesoonfoundthatapplyingfiretofoodcouldchangeitstextureandtaste,andthatmixingfirewithmudcouldproducehardsubstancesthatcancontainfood.ThiswashowceramicswasdiscoveredanddevelopedduringtheStoneAge,theperiodpriorto8000BCE. Ancientcivilizationswereinterestedinmetallurgy,pottery,anddyes.ThesecraftsweresuccessfullydevelopedinEgyptandMesopotamia.Thediscoveryofgoldin6000BCEandcopperin4020BCEwereimportantbreakthroughsinmetallurgy.By2000BCE,peoplewereproducingbronzebyheatingcopperandtinorestogether.Bronzewasastrongenoughmaterialtobeusedinweapons.Hence,thisperiodisknownastheBronze Age.Around1500BCE,theIronAgeemergedwhenpeoplelearnedtoextractironfromitsorebyapplyingmoreheat.Ironwouldcombinewithcarbonduringtheprocess,strengtheningitandproducingsteel,amalleableandstrongalloy.By900BCE the Egyptianswerealreadyexperimentingwithotherformsofchemistry,particularlythemummificationorthepreservationofhumanbodieswithpigmentsandnaturaljuices.

TheGreekphilosophersfirstformulatedthebasicideasofelementandcompoundfrom500to300BCE.Empedoclesintroducedatheorythatallmatterismadeupoffourelementalsubstances—earth,air,fire,andwater—indifferentproportions.Democritusbelievedthatallmaterialsaremadeupofindivisible,indestructible,andinfinitelysmallparticleswhichweregroupedtogetherindifferentproportionstoformthedifferentmaterials.Hecalledthisindivisibleparticleatomos,

whichgavebirthtowhatispresentlycalledatom.AristotlesupportedEmpedocles’ideaoffourelementsandDemocritus’ideaoftheatom.Hesuggestedthatthereweretwopairsofoptions—hotandcold,moistanddry—whichprovidedtheexactnatureofmatter.Hedescribedearthascoldanddry,airashotandmoist,fireashotanddry,andwaterascoldandmoist.

Fig. 1.1 Ancient people learned to use fire to cook food.

Fig. 1.2 The Greek philosophers

AristotleDemocritusEmpedocles


Alchemy WhenAlexandertheGreatestablishedtheRomanEmpire,ideasfromtheGreeksandthosefromtheEgyptianscametogetherandweretransferredtotheEmpire.TheArabscameinthe7thcenturyandstartedal-kimiya.Thegoalofal-kimiyawastofindthefollowing:

a. panacea–theappropriatecombinationofingredientsthatwouldcurealldiseases;b. aliksir (latercalledelixir)oflife–thesecretpotionthatwouldallowapersontobeimmortal;

andc. awaytotransformbasemetals(lead)intogoldusingthephilosopher’sstone.

Knightswhohadjoinedthecrusadesbroughthometheknowledgeof al-kimiyafromtheArabstotheEuropeans.Soon al-kimiyabecameknownasalchemywhichsomeEuropeanstookup.Despiteitsgrowingpopularityanduse,alchemywassteepedinmysticismandculturethatpeoplefoundithardtoestablishthesciencebehindtheperceivedmagicorsorcery.Theabsenceofadefinedscientificmethodmadealchemythriveforalongtime.

Inthe1500s,alchemywasintegratedtomedicinewiththeonsetofiatrochemistry,inwhichchemicalknowledgewasusedintreatingdiseases.Unfortunately,iatrochemistrywasstillfarfromthemodernchemistryaspeopletodayknowitbecausethosewhopracticediatrochemistryfailedtopresentfindingsbasedonalogicalscientificexperiment.Despitetheirefforts,alchemistswereneverabletotransmutecheapmetalsintogoldorfoundtheelixiroflife.

Getting to Know the Alchemists

Alchemyhasbeenpresentedinpopularmediasuchasanimationandfilms.Alchemistsareoftendepictedassorcerersanddruidswhohavemagicalorsupernaturalpowers.Inthisactivity,youwillgainawarenessofhowalchemistsaredepictedinseveralcountries.

Usesciencebooks,encyclopedia,ortheInternettoresearchthreealchemistsfromthreedifferentcountries.Basedontheinformationyouhavegathered,createafictionalalchemist.Illustrateyouralchemistandmakeacharacterprofile.Thecharacterprofilemaybeintheformofabiodataornarrative.

Answerthefollowingquestionstoguideyouinmakingthecharacterprofileofyourfictionalalchemist.

1. Whatisthenameofyouralchemist?2. Whatishisorhergender?3. Whatishisorhernationality?4. Howoldisheorshe?5. Whatishisorherphysicalfeatures?6. Whatishisorheroverallpersonality?

7. Whatarehisorhercurrentalchemyprojects?Discussthetools,chemicals,andprocessesusedbyyouralchemist.

8. Whatarehisorherdiscoveriesandinventionsrelatedtoalchemy?Describebrieflyhisor herdiscoveriesandinventions.

Try It Out!


Fig.1.3 Antoine Laurent Lavoisier, the father of modern chemistry

Fig. 1.4 John Dalton

Traditional Chemistry Theperiodoftraditionalchemistry,alsoknownasprimitive modern chemistry,coverstheendofthe17thcenturyuntilthemid-19thcentury.Itisaperiodoftransitionfromalchemytomodernchemistry.

In1661,RobertBoylepublishedhisbookThe Sceptical Chymist (The Skeptical Chemist),whichfocusedontheimportanceofthescientificmethod.Whenthescientificmethodwasdefinedandpracticed,itpavedthewayforexperimentsandinvestigationsonmanyscientificqueriesandproblems.Thiswassuchadefiningperiodforchemistry.Forthis,Boylehasbeenregardedasthefatherofchemistry.

Thescientificmethodwasveryusefulinprovingordisprovingcertaintheoriesduringtheearlyyearsofchemistry.TwoGermanchemistsJohannJoachimBecherandGeorgErnstStahlintroduced the phlogiston theorywhichstatesthatallflammablematerialscontainphlogiston,asubstancewithoutcolor,odor,taste,orweightthatisreleasedinburning.Whenasubstanceisburned,phlogistonwassupposedlyaddedfromtheairtotheflameoftheburningobject.Insomesubstances,

aproductisformed.

In1776,AntoineLaurentLavoisierdisprovedthephlogistontheory.Herealizedthatthepartofairthatcombineswithsubstancesastheyburnwasoxygen,thenamehegavefor“dephlogisticatedair.”Herecognizedthetruenatureofcombustion,discoveredoxygenandhydrogen,madethefirstlistofallelements,introducedanewchemicalnomenclature (asystemofnames),helpedconstructthemetricsystem,andwrotethefirstmodernchemistrytextbookTraité Élémentaire de Chimie.Thelawoftheconservationofmassduringchemicalreactionswasalsobasedonhisdiscussions.Thislawstatesthatthemassesofthereactantsareequaltothemassesoftheproductsafterachemicalreaction.Withhisnumerouscontributionstochemistry,Lavoisierwasconsideredthefatherofmodern

chemistry.

Modern Chemistry Theperiodofmodernchemistrycoversthemid-19thcenturyuptothepresent.Inthe1800s,theorderandvitalunderstandingofproportionsandstandardsinchemistrycameabout,causingchemistrytoflourish.

InspiredbyLavoisier’sworks,JohnDalton,anEnglishchemist,meteorologist,andphysicist,establishedhisatomictheory,whichledtofurtheradvancementsinchemistry—themostsignificantofwhichwasthecreationoftheperiodictable.Theperiodictablegavewaytoauniversalclassificationmethodoftheelements.

Manydiscoveriessoonfollowedsuchasthoseinvolvingsubatomicparticles,chemicalbonding,andradioactivityandnuclearreactions.Chemistryhasapplicationstoalmosteverythingeventothehumanbody.Constantinvestigationsledtothemodernatomictheory,newsubatomicparticles,andappliedchemistry.Technologycontinuestoadvance,makingchemistrythescienceaspeopleknowit


Lesson 2 Chemistry: Its Role in Science, Technology, and Society

Sci-kick

Word Up

Searchthewordpuzzleforthedifferentbranchesofchemistrylistedbelow.Thewordsmaybespelledforward,backward,horizontally,vertically,ordiagonally.Useeachletteronlyonce.Thenlookupthemeaningofeachwordinadictionary.

analytical–combinatorial–food–forensic–green– inorganic–medicinal–organic–physical–polymer–

Do you have any idea how important chemistry is to the society?

P W L F N T R O W C C F L A R

V H V A L E R U I R W O A M H

K C Y Y I I E N N Z N R C H K

G U X S A R A R K Q L E I N D

H I P N I G O X G Y S N T P R

P H I V R C O T Q G W S Y S N

W C K O H M A B A X Y I L M K

V G N O L B P L I N Y C A P I

Q I S F X V P V S R I N N V Q

F C S J H H W O S K Z B A D N

M E D I C I N A L K B C M O Y

Y A N C M P O C O R S K J O B

D V N S C K N P B Y Y P S F C

K P R J V F K S L Z R M V U M

V U G R E M Y L O P I O V N Q

I think chemistry goes hand in hand with technology. Without chemistry, we won’t have the things that we have today like my fave chocolate drink and cake.


Science and Its Branches Sciencehasbeendefinedbydifferentpeopleindifferentways.Scientists,teachers,andstudentshavetheirowndefinitions.Canyougiveyourowndefinitionofscience? ThewordscienceoriginatedfromtheLatinwordscientia,whichmeans“knowledge.”ItisalsorelatedtotheLatinword scire,whichmeans“toknow.”Fromthis,sciencemaybedescribedassomethingthatpertainstoknowledgeandtheprocessofacquiringthisknowledge.Howdoesthisdefinitionofsciencecomparewithyours? Scienceisaverybigbodyofknowledgethatcanbedividedintoseveralareasofinterest.Itcanbedividedintothreemainbranches:social sciences, mathematics,andnatural sciences. Social sciencesstudyhumansocietyandsociallife.Mathematicsstudiesthenatureofnumbersandexplainscertainphenomenaorsituationsbyusingmathematicalmodels.Natural sciencesstudyeverythingfoundinnatureandmaybesubdividedintophysical sciencesand biological sciences. Physical sciences dealwiththenonlivingcomponentofnature,whilebiological sciences dealwiththelivingcomponent.Chemistry isaphysicalsciencethatdealswithmatter.

Technology Theword technology camefromtheGreekwordtekhne,whichmeans“art”or“skill,”andlogia,whichmeans“thestudyof.”Thus,technologymaybedefinedasthestudyofanartoraskill.Itisastudyofcraftingormakingthings.Itcanbedefinedastheuseofscientificknowledgeorprinciplestocreatethingsthatwilladdresspeople’sneeds.Itmakeslifeeasierandmoreconvenient.Technologyistheapplicationofscience. Technologycanbeclassifiedintoproductsandprocesses.A technological product isanobjectorinfrastructurethathelpspeopleintheirdailytasks.Tools,machines,gadgets,andbuildingsaretechnologicalproducts.Atechnological processisasystemorasetofproceduresthatpeoplecanusetoenhancetheirskillsandtalentsortobemoreefficientintheirwork.Fermentation,foodpreservation,andwaterpurificationaretechnologicalprocesses.Canyougiveotherexamplesforeachtypeoftechnology? Ideally,technologyshouldalwaysbenefithumanity.However,thedisadvantagesofsometechnologymayoutweightheiradvantages.Usingsuchtechnologymaybedetrimentalbothtohumanlivesandtheenvironmentinthelongrun.Moreover,somepeoplemayusetechnologyforpersonalgainsratherthanforthecommongood.

Modern Technology: Is It In or Out?

Researchthreetechnologiesfromthreedifferentcountries.Completethetablebelowandshareitwiththeclass.

Technology:_________________________

Creator Features Advantages Disadvantages GoodorBad Reasons

Try It Out!


Oneofthetechnologiesthathavemadeagreatimpactonmanyaspectsofsocietyandpeople’sdailylivesisthecomputer.Peoplecannowdomanythingsthatwerenotpossibleorquitedifficulttodoyearsagowithoutcomputers.Moreover,withtheavailabilityoftheInternet,thereisasurgeofinformationandglobalawareness.TheuseofInternetmadecommunicationandinteractionamongscientistsandresearchersfasterandeasier.Theycanshareinformationwitheachotherandseekadviceorassistanceinresearchfromeachother.CanyougiveotheradvantagesoftheInternet? Inyourstudyofchemistry,youwillappreciatetheuseofinformationtechnology.YoumayfindtheInternettobeagreatsourceofinformationandavaluabletoolinyourstudy.However,noteverythingyoufindintheWebistrueoraccurate.SomeWebcontenthaveverylittlecredibility,whilesomearemereopinions.Thus,youmustbeabletoevaluatetheinformationthatyouobtain.Asasciencestudent,youaremainlyconcernedwithaccurateandvalidatedinformationandknowledge.

Willthereeverbeatimewhenpeoplearereplacedwithartificialintelligence(AI)?Withcomputerscontinuouslybeingimproved,somepeoplemaythinkthatthedaywillcomethatAIultimatelyreplacehumanbeings.Inchess,AIhasbeenemployedincreatingacomputerprogramnamedDeepFritz,whichdefeatedVladimirKramnik,aworldchampioninchess,in2006. DeepFritzisanimprovementofotherchessprogramscreatedinthe1980sand1990s.TheAIsforchess,whichincludedDeepBlueandDeepThought,havetheword“deep”intheirnamesasinfluencedbythenovelThe Hitchhiker’s Guide to the Galaxy.Inthenovel,anultimatethinkingcomputernamed“DeepThought”wasmadetoanswertheultimatequestionsonlife,theuniverse,amongotherthings. AIhasraisedethicalissuesandhasbeenatopicofdebateaboutthefutureoftechnologyandsociety.Theuseofcomputers,machines,androbotswithartificialintelligencehasadvantagesanddisadvantages.Butonethingiscertain,AIcanneverreplacehumans.Advancedtechnologiesare createdbypeopletomaketheirworkeasier andnottoreplacethem.

InfoOverload

Etymology of Chemistry Theword chemistryhasanumberoforigins.ItmayhavecomefromtheGreekwordkhemeia,whichmeans“metalworking.” ItmayhaveoriginatedfromtheArabwordal-kimiya,whichcanbeinterpretedinseveralways.Al-kimiyacanbetakentomeanEgyptianscience,notingthatEgyptwascalledkem-it.ItwasduringtheirconquestofEgyptthatArabscametoknowthistypeofknowledge.ItmayhaveoriginatedfromtheGreekwordkhymeia,whichmeans“theartofmeltingmetalsandalloyproduction.”In1530,GeorgAgricola,ahumanist,suggestedtodrop“al-”fromtheArabicwordal-kimiya,andreturnittoitsclassicalrootchymiaandchymista insteadoftheearlieralchymia andalchymista. ThiswasthenadoptedandtranslatedinFrenchaschimie;inGermanaschemie; in Italianaschimica;andinEnglishas chemistry.

Chemistry and Its Branches Chemistryisaphysicalsciencethatcanbedefinedasthestudyofmatteranditscompositionandstructure,thechangesitundergoes,andtheenergyassociatedwiththesechanges.Itconsistsofmanyspecializedfieldsandinteractswithallotherareasofscience.Hence,itisconsideredacentral


science.Itrelatestomanysciencesthatdealwithnature,suchasphysics,biology,astronomy,andgeology.Sincenatureismadeupofmatter,theneverythinginnaturemaybeexplainedandfurtherinvestigatedusingchemistry.Thus,chemistrycanbeintegratedwithalltheothersciences,leadingtotheformationofitsdifferentbranchessuchasthefollowing:

1. Inorganic chemistry –isthestudyofthechemicalnatureoftheelementsandtheircompoundsnotcontainingcarbonandthatarenotorganic.ExamplesofsuchsubstancesaremineralsfoundinEarth’scrustandnonlivingmatter.

2. Organic chemistry –isthestudyofcompoundsconsistinglargelyofhydrocarbons(compoundscontaininghydrogenandcarbon),whichprovidetheparentmaterialforallotherorganiccompounds.Carbonisstudiedseparatelybecauseofitsuniquesharingpropertieswhichallowittoformringsandlongbranchedchains,producinghundredsofthousandsofcarbon-basedmolecules.Organiccompoundsareparticularlyimportantbecausetheymakeupthemajorityofcompoundsinlivingorganisms.

3.Physical chemistry –dealswiththeapplicationofphysicallawstochemicalsystemsandchemicalchange.Itisconcernedwiththeroleofenergyinchemicalreactions.

4.Analytical chemistry –dealswiththequalitativeandquantitativedeterminationofchemicalcomponentsofsubstances.

5. Biochemistry–isthechemistryoflivingorganismsandlifeprocesses.Itisconcernedwiththecompositionandchangesintheformationoflivingspecies.

6.Geochemistry–istheapplicationofchemistrytoprocessestakingplaceonEarth,suchasmineralformation,metamorphosisofrocks,andformationandmigrationofpetroleum.

7. Radiochemistry–isthestudyofthechemicaleffectsofhigh-energyradiationandthebehaviorofradioactiveisotopes,atomsofthesameelementthatvaryinthenumberofneutronstheyhave.

8.Macromolecular chemistry or polymer chemistry–dealswiththechemicalsynthesisandchemicalpropertiesofpolymers.

9.Environmental chemistry –isthestudyofthechemicalandbiochemicalphenomenathatoccurinnaturalplaces.

10.Green chemistry–isthestudyofthedesignofchemicalproductsandprocessesthatreduceoreliminatethegenerationanduseofhazardoussubstances.

11.Electrochemistry–isthestudyofthereactionsthatcantakeplaceattheinterfaceofanelectronicconductorandanionicconductor(anelectrolyte).

12.Photochemistry –isthestudyoftheinteractionoflightandchemicals.13.Astrochemistry–isthestudyofthecompositionandreactionsofchemicalsfoundinstars

andinspace,aswellastheinteractionsbetweenmatterandradiation.14.Food chemistry–isthestudyofthechemicalprocessesinfood.15.Medicinal chemistry–isthestudyoftheapplicationsofchemistrytopharmacologyand

medicine.16.Forensics chemistry–isthestudyoftheapplicationofchemistrytolawenforcement.It

involveschemicalanalysisofsubstancesthatmayhavebeenusedinacrimescene.17.Combinatorial chemistry–isthestudyofsynthesizingsubstancesquicklyandinexpensively

usinginnovativemethods.

Discover Science: Chemistry10

Chemistry in Everyday Life Chemistrytouchespracticallyeveryaspectofyourlife.Itisinvolvedinyouressentialneeds,suchasfood,shelter,clothing,energy,andcleanenvironment. Everythinginthisworldismadeupofchemicals.Yourbodyismadeupofdifferentelementssuchashydrogen,oxygen,carbon,nitrogen,andotherelements.Yourdifferentbodysystemsinvolvedifferentchemicalsandchemicalreactions.Digestionisachemicalprocessthathelpsyourbodygettheessentialnutrientsfromthefoodyoueat.Thesenutrientsarecarriedbyyourbloodtovariouspartsofyourbodytobuildnewcellsandproduceenergyforyourdailyactivities. Respirationisanotherchemicalprocessbywhichglucoseisbrokendownandoxidizedtoprovideenergy.Italsoexplainswhathappenstooxygenwhenyoubreatheandwhycarbondioxideisreleasedwhenyouexhale.Itcanbesummarizedinthefollowingequation:

C6H12O6+6O2→6CO2+6H2O+energy

glucose oxygen carbon dioxide water Recallhowplantsproducetheirownfoodthroughphotosynthesis,aprocessimportantforthesurvivalofpeopleandanimals.Plantsgiveoffoxygenthatpeopleandanimalsneedtolive. Thechemicalreactionofphotosynthesiscanbesummarizedbythefollowingequation:

6CO2+6H2O+lightenergy→C6H12O6 +6O2 Canyouthinkofotherchemicalreactionshappeninginyourdailylife?

Chemistry and the Society Chemistryimprovesthequalityofpeople’slivesinvariousways.Itprovidespeoplewithnewproductsandprocessestosatisfytheirneedsandsolveproblemsinhealth,resources,andenvironment.Researchesinchemicalsledtothediscoveryanddevelopmentofsyntheticfibers,paints,adhesives,drugs,cosmetics,electroniccomponents,lubricants,andthousandsofotherproducts.Theyalsoledtothedevelopmentofprocesses,suchasimprovedoilrefiningandpetrochemicalprocessingthatsaveenergyandreducepollution.

Researchesonthechemistryoflivingthingsspuradvancesinmedicine,agriculture,foodprocessing,andotherfields.Inmedicine,advancedmedicalequipmentandnewdrugsareconstantlybeingdevelopedtoprovidemoreaccuratediagnosis,monitoring,andtreatmentofdiseases.Theseincludecomputedtomography(CT)scanners,magneticresonanceimaging(MRI)machines,positronemissiontomography(PET),andlaser-assistedinsitukeratomileusis(LASIK)surgicalmachines.

Chemistsrespondtotheneedsoftheincreasinghumanpopulation.Agrichemistslookforwaystomakecropsmoretoleranttocertainpestsandherbicides;improvethetasteandcolor,andpromotelongershelflifeoffruitsandvegetables;andimprovethequalityofplantstoyieldmoreandbettercrops.

Theuseofcomputerstoanalyzecomplexdataopenedthedoortocombinatorialchemistry.Acombinatorialroboticsystemcanproducethousandsormillionsofcompoundsinayearagainst100to200compoundsthattraditionalchemistscanproduce.Asidefromsequencingofhumangenesandproductionofnewdrugs,combinatorialchemistsalsonowapplycombinatorialchemistrytootherfieldssuchassemiconductors,superconductors,catalysts,andpolymers.

The Building Block of Science 11

Today,manychemistsspecializeinspecificfields,suchasforensicandmaterialschemistry.A forensic chemistanalyzespiecesofevidencegatheredfromcrimescenes.Theyruntestsonapieceofevidenceandreachaconclusionbasedontheresultsofthesetests.Identifyingpiecesofevidenceisanimportantpartofthelargerprocessofsolvingacrime.Thishelpssolvecrimefasterandmoreaccurately.Amaterials chemiststudiesanddevelopsnewmaterialstoimproveexistingproductsormakenewones.

Chemicals Everywhere

Identifyatleastthreechemicalsyoucanfindineachplacelistedbelow.Writetheusesofeachchemical.

C-churchH-ospitalE-nvironmentM-arketI-ndustryS-choolT-ransportationR-estaurantY-ourhome

Chemists and Their Tasks Chemistsarescientistswhoseekandapplynewknowledgeaboutchemicals.Theyaretheexpertsinchemicalreactions,chemicalproducts,andchemicalprocesses.Theyconductscientificresearches,analyzesubstances,andsynthesizenewsubstances.Theyareneededinotherfieldssuchasengineering,medicine,education,business,culinaryarts,nutrition,sports,andcomputertechnology.

Someofthetasksofachemistareasfollows:1. Analyzedifferentchemicalssuchastheirphysicalproperties,composition,structure,and

reactionsusingvariedtechniques2.Design,develop,andcustomizedifferentproductsandprocesses3.Conducttestsandresearchestodeterminethevalidityofaprocessorequipmentandto

developorimprovenewproducts4. Preparedifferentchemicalsforexperiments,productionofnewmaterials,andotherindustrial

andresearchpurposes5.Communicatewithotherscientiststoshareinformation,seekadvice,criticizeresearchworks,

anddevelopresearches6.Writeresearchpaperstohavearecordofstudyconductedforreferenceandfurtherresearch

Try It Out!

Discover Science: Chemistry1�

Jöns Jacob Berzelius (20August1779–7August1848)Heformulatedthelaw of constant proportions,whichstatesthatinorganicsubstancesarecomposedofdifferentelementsinconstantproportionsbyweight.Hediscoveredtheelementssilicon,selenium,thorium,andcerium.Hewascreditedfororiginatingthechemicaltermscatalysis, polymer, isomer, andallotrope.

Friedrich Wöhler (31July1800–23September1882)Hecontributedtothedevelopmentoforganicchemistrybysynthesizingureainthelaboratory.Healsodiscoveredseveralelements.

Gilbert Newton Lewis (23October1875–23March1946)Hecontributedtotheunderstandingofthecovalentbondandchemicalthermodynamics.

Glenn T. Seaborg(19April1912–25February1999)Hediscovered10transuraniumelements,namely,plutonium,americium,curium,berkelium,californium,einsteinium,fermium,mendelevium,nobelium,andseaborgium.

Roy J. Plunkett (26June1910–12May1994)HeaccidentallyinventedTeflon(theDuPonttrademarknameforpolytetrafluoroethyleneorPTFE).Teflonisnonstickcoatedcookware.

Foreign Chemists Manyscientistshavecontributedtothedevelopmentofchemistry.Perhapsyoucancontributetochemistryastheydidespeciallyifyoudecidetospecializeinthisfield.

Filipino Chemists HerearesomeFilipinochemistsandtheirrespectivecontributionstochemistry:

Anacleto del Rosario (13July1860–2May1895)Hestudiedproducingapurekindofalcoholfromtuba of nipapalm. HeisregardedasthefatherofPhilippinescienceandlaboratory.

Julian Banzon (25March1908–13September1988)Heresearchedonthedifferentmethodstoproducealternativefuel.

The Building Block of Science 1�

An Interview with a Chemist

AskyourrelativesandfriendsiftheyknowachemistworkinginthePhilippines.Ifnot,searchtheInternetorlookupatelephonedirectoryforcompaniesrelatedtochemistry.Lookforachemistandsetupanappointmentforaface-to-faceinterview,ifpossible.Ifnot,gethisorhere-mailaddressandinterviewhimorherviae-mailorchat.Supplytheinformationlistedbelow.Shareyourworkwiththeclass.

1. Name 2. Age 3. Educationalbackground4. Nameofcompanyandlocation5. Positionandnatureofwork

Basedonyourinterviewee’sresponses,answerthefollowingbriefly.

1. Wouldyouconsiderbecomingachemistsomeday?Why?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

2. WhatarethepossiblejobsofferedtochemistsinthePhilippines?__________________ _______________________________________________________________________

_______________________________________________________________________ _______________________________________________________________________

3. AreFilipinochemistscontributingtoourcountry’sdevelopment?_________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________

Amando Kapauan (4July1931–12October1996)Hefocusedonstudyingtheeffectsofheavymetalsinourenvironment.

Baldomero Olivera (1941–present)Hediscoveredconesnailtoxinsorconotoxins.Hediscoveredziconotide(Prialt),apainrelieverusedforchronic,intractablepainforpeoplewithcancer,AIDS,orcertainneurologicaldisorders.

Try It Out!


Lesson 3 The Processes, Tools, and Techniques in Chemistry

Word Up

Nameeachapparatusandwriteyouranswerineachbox.

Sci-kick

I’ve borrowed some tools. I have to finish my science project at home.

What do you have there with you, Kiko?


Science Process Skills Asyoustudychemistry,youwillneedthesameprocessskillsthatscientistsusewhentheywork.Scienceprocessskillsarethetoolsyouneedtounderstandthemechanismsofthematerialworld.Ascientificallyliteratepersonusestheminsolvingproblems,makingdecisions,andunderstandingfurtherthesocietyandtheenvironment.Developingtheseskillswillallowyoutothinkcreativelyandcriticallyandhelpyousatisfyyourcuriosity.

1. Observing

Observationisthemostfundamentalofalltheprocesses.Whenyouobserve,yougatherinformationthroughtheuseofoneormoreofyoursenses(orinstrumentsthatextendoursenses):sight,hearing,touch,taste,andsmell.Observationisinfluencedbyyourpastexperiences.Itofteninvolvesinstrumentsandrequirescarefulrecordinganddescription.Surprisingorunexpectedobservationsoccasionallycontributenewandimportantknowledge.Thegatheredinformationorobservationsarecalled data or facts.

Anobservationmaybequalitativeorquantitative.Aqualitative observationinvolvesusing asmanysensesaspossible.Itdescribesanobject,asituation,oraneventusingonlywords. Aquantitative observationmakesuseofnumbers,aswellaswords,inthedescriptionofanobject,asituation,oranevent.Toolsordevicesareusedtomeasurethecharacteristicbeingdescribed.

BasedonFigure1.5,thescientistmayhavethefollowingobservations:

Qualitative Quantitative

1.Eachtesttubecontainsasmall amountofliquid.

1.Therearefivetesttubesintherack.

2.Thefirsttesttubecontainsaclearliquid. 2.Thethirdtesttubecontains3mLofgreenink.

2. Measuring

Measuringiscomparinganunknownquantitywithaknownstandardofreference.Measurementsaretoberecordedsystematicallywithlabeledunitsofmeasure.Theyshouldbepreciseandaccurate.Length,volume,mass,temperature,timeintervals,andforcearecommonquantitiesthataremeasured.

3. Inferring

Aninferenceisanexplanationofanobservationintermsofapreviousexperience.Inferringisaprocessskillwhichallowsyoutoblendyouruniqueinterpretationwithyourobservations.Inscience,inferencesabouthowthingsworkarecontinuallyconstructed,modified,andevenrejectedbasedonnewobservations.Forexample,astudentwhoobservedawhitespotonhisorherblackshirtmayinferthathisorhermotherusedbleachinwashinghisorherclothes.

Fig. 1.5 A scientist working in the laboratory


4. Classifying

Classificationistheprocessofgroupingororderingobjectsbasedonobservabletraits.Objectsthatshareagivencharacteristiccanbesaidtobelongtothesameset.Classifyinginvolvesgroupingobjects,concepts,oreventsbasedonobservablepropertiestoshowsimilarities,differences,andinterrelationships.Wastesegregationisanexampleofclassification.

5. Predicting

Predicting isforminganideaofafutureoccurrencebasedonobservationsandinferences.Apredictionmaybeusedtogeneralizethatunderacertainsetofcircumstances,acertainoutcomemaybeexpected.Itmaybeusedtodescribeoutcomesbeyondtheobserveddata.Forexample,youarecollectingdataonthetemperatureofwater.Ifthereadingsare30°C,32°C,34°Cfor3minutes,youcanpredictthatafter5minutesofheating,thetemperatureofwaterwillbe38°C.Thisiscalled interpolation. Ininterpolating,predictionsaremadewithintherangeofgivendata.

6. Communicating

Communicatingistheprocessoforganizingandprocessingdatausingwords,symbols,orgraphicstodescribeanobject,asituation,oranevent.Ascientistisobligedtomaketheinformationavailabletothecommunityforindependentconfirmationandtesting.Scientistsdisseminatetheresultsoftheirstudiesinjournals,scientificmeetings,seminars,andinformalnetworks.Thisdisseminationcontributestothecommoncoreofknowledgeofthepastandprovidesthevehicleforcontinuousreviewofthisbodyofknowledgeandforadvancementsinscience.

7. Hypothesizing

Hypothesizingisstatingtheproposedsolutionsorexpectedoutcomesforyourinvestigationsorexperiments.Itisanintrinsicandcreativementalprocess.Ahypothesisshowstheexpectedrelationshipbetweentwovariablesinanattempttoexplainacause-and-effectrelationship.Itshouldbetestable.Itistestedtohelpexplainobservationsthathavebeenmade.Itisoftenstatedasan“ifandthenstatement.”Anexampleofahypothesisis“Ifsaltisaddedtowater,thenitwillboilfaster.”

8. Defining Operationally

Todefineoperationallyistodescribeobjectsinthecontextofacommonexperience.Anoperationaldefinitiontellsonewhattodotoorwithanobjectandwhattoobserveasaresultoftheaction.Itiswrittenintermsofhowanobjectworksorhowitcanbeused.Examplesofoperationaldefinitionsaregivenbelow:

Object OperationalDefinition

Arulerisatoolthatmeasuresthelengthofanobject.


Abicycleisatwo-wheeledmodeoftransportation.

Abicyclecanmoveapersonfromoneplacetoanother.

Apenisatoolforwriting.

9. Controlling Variables Avariable isachangeablefactorthatcanaffectanexperiment.Controllingvariablesinvolvesdecidingwhichvariablesorfactorswillinfluencetheoutcomeofanexperiment,situation,orevent,anddeliberatelycontrollingthemsystematically.Notehowimportantitistochangeonlythevariablebeingtestedandkeeptheothervariablesconstant.Ifyouallowmorethanone variabletobechanged,youcannotdeterminethecauseofthechangesyouobserveintheindependentvariable.Thevariableyouplantoexperimentwithisthemanipulated or independent variable,whiletheonebeingmeasuredtodetermineitsresponseistheresponding or dependent variable.Thevariablesthatyoucontrolormadethesameinyourexperimentaretheconstant variables.

(a) control (b) experimental

Fig. 1.6 The effect of salt on the boiling temperature of water

Manyexperimentshaveacontrolvariable,whichisatreatmentthatyoucancomparewiththeresultsofyourtestgroups.Intheexperimentonthetemperatureofhotwaterupontheadditionofsalt,everythingshouldbethesameexceptthepresenceofsalt.Thebeaker,theamountofwater,andothermaterialsshouldbethesame.Thesetupinwhichsaltisnotadded(setupA)isthe control.Thesetupinwhichtwotablespoonsofsaltisadded(setupB)istheexperimental or test group.Inthisexperiment,saltistheindependentvariable,temperatureisthedependentvariable,andalltherestofthematerialsaretheconstantvariables.Theuseofexperimentalandcontrolsetupsareonlytwowaysofcontrollingvariables.


10. Designing Experiments

Designinganexperimentincludesidentifyingmaterialsanddescribingappropriatestepsinaproceduretotestahypothesis.Aprocedureistheplanthatyoufollowinyourexperiment.Itincludesthematerialsneededandhowtousethem.

11. Experimenting

Experimentingiscarryingoutanexperimentbycarefullyfollowingthestepsintheproceduresothattheresultscanbeverifiedbyrepeatingtheprocedureseveraltimes.

12. Acquiring and Organizing Data

Acquiringdataistheprocessofcollectingqualitativeandquantitativeobservations.Datacanbeorganizedinseveralwayssuchasusingtablesandgraphs.

13. Interpreting Data

Interpretingdatainvolvesanalyzing,synthesizing,andevaluatingtrendsorpatternsinasetofdata.Thesepatternsmaybeusedtoformulatehypotheses,makepredictions,anddrawgeneralizations.Interpretationrequirescreativethinkingthatcanresultinawholeideathatencompassesthedata.

14. Identifying Cause-and-effect Relationship

Identifyingcausesandeffectsrequiresanalyticalthoughtasoneseekstodistinguishcausefromeffect.Thecausealwayshappensbeforetheeffect.Theeffectisaresult.Youidentifycause-and-effectrelationshipseverydaywhenyousolveproblemsandmakedecisions.Learningtoidentifycause-and-effectrelationshipscanhelpyouunderstandwhathashappened.

15.Formulating Models

Formulatingmodelsincludesdescribingorconstructingphysical,verbal,mental,ormathematicalexplanationsofsystemsandinterconnectedphenomenathatcannotbedirectlyobserved.Amodelisusedtosimplifyprocessesorstructures.

The Chemistry Laboratory Chemistsneedaplacetoconductexperimentsandresearches,andthelaboratoryistheidealvenue.Manychemicalproductshavebeensynthesizedandvariouschemicalshavebeendiscoveredinlaboratories.Forachemistrystudent,alaboratoryiswhereyouwillapplythedifferentchemicalprinciplesthatyouwilllearn.

Safety in the Laboratory

Actualparticipationinthelaboratoryworkisessentialinthestudyofchemistry.Ideally,achemistrylaboratoryshouldhavethefollowing:(a)ventilationsystem,(b)sink,(c)worktable, (d)gasandwateroutlets,(e)trashbin,(f)fireextinguisher,(g)firstaidbox,(h)boardforwriting, (i)cabinetsforstorage,and(j)fumehood.However,alaboratorymaynothaveallofthesethings. Ifthatisthecase,thencertainexperimentscannotbecarriedoutinthelaboratory.


Somethingsinthelaboratoryaretherenotonlyforlearningbutalsotomaintainsafety.Safetyalwayscomesfirst.Inthechemistrylaboratory,youwillbeworkingwithanequipmentoramaterialthatmaycauseaccidentsifnothandledproperly.Accidentsdohappen;thatiswhyeveryprecautionmustbetakentopreventthem.Followthebasicsafetyruleswhileworkinginthelaboratory.

1. Alwaysfollowyourteacher’sinstructions.Listenintentlyandmakesurethatyouunderstandeverythingthatyouhavetodo.Prepareeverythingyouneed.

2. Takeonlythematerialsthatyouareaskedtobringtothelaboratory.Rememberthatfoodanddrinksarenotallowedinsidethelaboratory.

3. Avoidplayinginsidethelaboratory.

4. Handlechemicalswithcaution.Disposeofchemicalwastesandotherwastesproperly.

5. Usealllaboratorytoolsproperly.Handlethemwithcaretoavoidbreakage.Checktheirconditionsbeforeyouusethem.

6. Donotdeviatefromtheexperimentalprocedures.

7. Wearprotectiveclothingsuchasalaboratorygown,anduseprotectivegadgetssuchasgoggles,masks,andgloves,ifnecessary.Ifyouhavelonghair,tieitbackorwearahairnet.

8. Reportanyinjuryoranyuntowardincidenttoyourteacherwhoisalwaysthereto

Fireisthemostcommonserioushazardinatypicalchemistrylaboratory.Whileproperprocedureandtrainingcanminimizethechancesofanaccidentalfire,youmuststillbepreparedtodealwithafireemergency. Thedifferentclassesoffireareasfollows:

• ClassA–ordinarycombustibles(wood,paper,plastics)

• ClassB–flammableandcombustibleliquids• ClassC–flammablegases• ClassD–combustiblemetals• ClassE–electricallyenergizedequipment• ClassF–cookingoilsandfats

Fireextinguishersarecolorcodedsothatyoucanidentifythemquicklyandusetherighttypeofextinguisherforacertainclassoffire.Thetwomostcommontypesofextinguishersinthechemistrylaboratoryarepressurizeddrychemicalandcarbondioxideextinguishers.DrychemicalextinguishersareusefulforclassABC fires,andhence,abetterchoiceforthechemistrylaboratory.Theyleaveablanketofnonflammablematerialontheextinguishedmaterial,whichreducesthelikelihoodofreigniting.Carbondioxideextinguishers,ontheotherhand,aremosteffectiveonclass BandC fires.TheydonotworkverywellonclassAfiresbecausethematerialusuallyreignites.Theydonotleaveharmfulresidue.Sincethegasdispersesquickly,carbondioxideextinguishersareonlyeffectivefrom3to8feet.Acarbondioxideextinguisherisagoodchoiceforanelectricalfireinvolvingacomputerorotherdelicateinstrument.Itisnotsuitableforoutdooruse. AneasyacronymonusingfireextinguishersisPASS:Pull thepinthatkeepsthehandlefrombeingaccidentallypressed.Thepinislocatedatthetopoftheextinguisher.

Aimthenozzletowardthebaseofthefire.Remembertostandapproximately8feetawayfromthefire.

Squeezethehandletodischargetheextinguisher.Onceyoureleasethehandle,thedischargewillstop.

Sweepthenozzlebackandforthatthebaseofthefire.Afterthefireappearstobeout,watchcarefullyforpossibilityofreignition.

InfoOverload

Discover Science: Chemistry�0

Safety Symbols

Safetysymbolsareusedinthelaboratorytoemphasizespecifictypesofprecautions.Theyareusedasaidstocommunicateinformationonhazardsandtheneedforpersonalprotectiveparaphernalia,andgiveguidanceandinstructionincaseofemergency.Remembertotakethenecessaryprecautionwhenyouseesafetysymbols.

Safety ClothingItremindsyoutowearyourlaboratorygownproperly.Alaboratorygownprotectsyourskinandyourclothesfromanykindofspills.

Eye SafetyItappearswhenadangertotheeyeexists.Youshouldwearsafetygoggleswhenyouseethissymbol.

Chemical SafetyItremindsyouthatthechemicalsyouusearecorrosive.Corrosivematerialsareusuallystrongacidsorbases.Theycancauseburnsonyourskin.

Fire SafetyItremindsyouthatthechemicalyouuseisflammable.Thisalsoremindsyouthatcareshouldbetakenaroundopenflames.

Thermal SafetyItremindsyoutousecautionwhenhandlinghotobjects.

Explosion SafetyItremindsyouthatthemisuseofchemicalscancauseanexplosion.

helpyou.Donothesitatetoaskyourteacherifyouhaveanyquestion.9. Returnallchemicalsandlaboratorytoolstothestockroomorstoragearea.Donottake

homeanychemicalorlaboratorytool.10.Refrainfromusingcellphonesandotherelectronicgadgetsinthelaboratory.Removeall

piecesofjewelrywhileworkinginthelaboratory.11.Washyourhandsafterhandlingchemicals.Cleanalsothelaboratorymaterialsthatyouhave

used.12.Donotplaywithchemicalsandfire.Nevertasteanysubstanceinthelaboratoryunlessyou

aretoldtodoso.13.Learnhowtoputoutfire.Yourteacherwilldemonstratehowtousethefireextinguisherif

thelaboratoryhasone.14.Ifacidisspilledonyourskin,washitwithrunningwaterandsodiumcarbonate.Washit

againwithwaterafterward.15.Ifabaseisspilledonyourskin,washitwithwaterandthenwith1%aceticacidsolution.

Washagainwithwaterafterward.

The Building Block of Science �1

Disposal AlertIttellsyouthatyou candiscardthechemicalsdownthedrain.

Recycling AlertItremindsyouthatthematerialscanbestoredandrecycled.

Electrical SafetyItremindsyouthatcareshouldbetakenwhenusingelectricalequipment.

Hygiene SafetyItremindsyoutowashyourhandsthoroughly.

Poison SafetyItindicatesthepresenceofatoxicorpoisonousmaterial.

Dispose AlertsItremindsyoutothrowusechemicalsandmaterialsintheproperdisposalarea.

Laboratory Tools

Chemistryinvolveslaboratoryinvestigations.Youmustknowthebasicapparatususedinchemistrytoensurethatyourinvestigationsproceedsmoothly.Thefollowingarethecommontoolsthatyouwilluseinthelaboratory:

Alcohol burner –isasourceofheat.

Stirring rod –isusedforstirringsubstancesandtransferringliquidstoanothercontainer.

Beaker –isusedtocontainliquids.

Pipette bulb or aspirator –isusedtocleanthepansofplatformbalanceandgetliquidusingapipette.

Bunsen burner–isasourceofheat.

Platform balance –isusedtomeasurethemassofasubstance.

Discover Science: Chemistry��

Burette –isusedtomeasurevolumeof solutions during titration.

Reagent bottle –isa storagevesselofchemicals.

Ceramic square –supportshotapparatustopreventbreakage.

Rubber stopper – supportsthermometerandcoverstheopeningsofnarrow-mouthedcontainers.

Clay triangle –supportsacrucible.

Rubber tubing–connectsaBunsenburnertoagasoutlet.

Crucible tongs –is usedtoholdacrucibleanditscover.

Test tube brush–isusedtocleanthetesttubes.

Double burette clamp–supportsburetteduringtitration.

Erlenmeyer flask –isusedtocontainliquids.

Test tube clamp or utility clamp – supportsthetesttubeandburette.

Test tube holder –isusedtoholdatesttube.

The Building Block of Science ��

Evaporating dish –isusedtoevaporateliquids.

Test tube rack –supportstesttubes.

Flame loop –is used to hold chemicalsduringflametest.

Thermometer – is used tomeasuretemperature.

Florence flask–isusedtoboilliquidsolutions.

Triple beam balance–isusedtomeasuremassofasubstance.

Forceps–isused togetsmallobjects.

Tripod –supportstheclaytriangleorwiregauze.

Funnel –isusedtotransferliquidstoanothercontainerandsupportfilterpaperduringfiltration.

Volumetric flask –isusedtomeasurevolumeofliquids.

Graduated cylinder –isusedtomeasurevolumeofliquids.

Wash bottle–isusedtowashtheinnersidesoftheapparatus.

Iron ring– supportsthewiregauzeorclaytriangle.

Watch glass –isacontainerusedtoobservesmallspecimens.


Iron stand– supportstheironringorclamp.

Wire gauze –regulatesheatoftheflame.

Dropper pipette or dropper –isusedtotransfersmallamountsofliquidstoanothercontainer.

Spot plate –isareactionvesselusedforsmallamountsofsubstances,especiallywhenusinglitmuspaper.

Mortar and pestle–isusedforpoundingorgrinding solid chemicalstopowderform.

Spatula –isusedforgettingsolidchemicalsfromreagentbottles.

Crucible and cover –isavesselusedinheatingsmallamountsofsolidsubstancesathightemperature.

Fish tail –isusedforspreadingtheflameofBunsenburner.

Bell jar –isusedtocoverandstorevolatilechemicals.

Glass tubing delivery tubes –isusedtomakedroppersforcapillarytubes.

Desiccator–isusedforremovingthe moisture from specimens.

Syringe –isusedforsuckingandexpellingliquidinfinestream.

Measuring pipette –measuresexactvolumeofliquids.

Transfer pipette–isusedtotransferliquids.


Designandmakeyourownlaboratoryapparatus.Demonstrateitsuseinclass.Thenfilloutthefollowinginformation:

Nameoflaboratoryapparatus:Use:Materialsandcost: Howitlookslike: Howitworks:

Laboratory Techniques Conductinganexperimentisthebestwaytolearnchemistry.Poorresultsinachemistryexperimentareoftentheresultofpoorlaboratorytechniques.Alaboratorytechniqueisnotrandom,butarationalapproachtoaproblem.Themostcommonerrorsinachemistryexperimentarechemicalcontamination,thelossofprecipitates,spilledliquids,andthelike.Toavoidtheseerrors,youmustpracticegoodbasiclaboratorytechniques.

Using Chemicals Chemicalsarestoredinreagentbottles.Alwaysreadthelabelonareagentbottlebeforeusingitscontents.Removethelidandplaceitontopofthetableupsidedown.Getonlythedesiredamountofthechemicalyouneed.Nevertouchachemicalwithyourhands.Useaspatulaforsolidsandadropperforliquids.

1. Solids

Toobtainasolid,removethelidorstopperandplaceitupsidedownonthetable.Rotateandtiltthebottleatthesametimetodispensethesolidslowlytoacleandrybeaker.

Youcanalsouseacleandryspatulatospoonoutasmallamountofthesolid chemical.

CSI

Ifthecontainerhasanarrowmouthlikethatofatesttube,useafoldedorrolledpaper,thengentlytapthepapertotransferitscontentintothetesttube.

2.Liquids

Toobtainaliquidfromareagentbottle,grasptheverticalflangebetweenyourthirdandfourthfingers,palmsup.Holdingtheflangethisway,bringtheneckofthebottleincontactwith


therimofthereceivingcontainer.Pourtheliquiddownthesidetoavoidspatteringandspilling.Replacetheflangewhenfinished.Note: Theflangemustnevertouchthelaboratorycountertoporthesideofthereceivingcontainertoavoidcontamination.

Totransferaliquidusingapipette,useanaspiratortoavoidcontamination.Placeanaspiratorontop

ofthepipetteasillustrated.Compresstheaspirator.Slowlyreleasepressuresothattheliquidisdrawnintothepipette.Removetheaspiratorandsimultaneouslyplaceyourindexfingerovertheendofthepipette.Insertthetipofthepipetteintothereceivingcontainer.Holditverticallyandallowpipettetodrainfreely.

Liquidscanalsobetransferredwiththeuseofastirringrod.Pourliquidsintoanothercontainerusingaglassrodinanuprightpositionofthereceivingcontainer.

Inobtainingliquidsfrombottlesequippedwith

medicinedropper,besurethatitnevertouchesboththecontainerandthecontentsofthereceivingvessel.

Measuring Liquids

Thegraduatedcylinderandpipettearetwocommonlyuseddevicesformeasuringliquidvolumes.Studycarefullytheparticulardevicetodeterminehowitiscalibratedandhowtouseittomeasureliquidsaccurately.Whenreadingthelevelofliquidinanyliquidmeasuringdevice,readthebottomofthemeniscus(lowestportionoftheconvexdipoftheliquidasitsitsinthegraduatedcylinder),withyoureyeatthesamelevelastheliquidsurface.

Using the Laboratory Thermometer

Nevershakealaboratorythermometer.Immersethebulbofthethermometerinthesubstancewhosetemperatureyouaremeasuring.Allowthealcoholleveltostabilizeandreadthethermometer.Besuretostudythecalibrationsonthethermometertodeterminehowitcanbereadaccurately.Donotuseathermometerasastirringrodforsolutions.Rememberthatthebulbofthethermometerisdelicate.Ifathermometerbreaks,immediatelyinformyourteacher.


Using a Bunsen Burner

TheBunsenburnerisusedfrequentlyinthelaboratoryasasourceofheat.Itisdesignedsothatgaseousfuelmaybemixedwiththecorrectamountofairtoyieldthemaximumamountofheat.Itcanproducethreedifferenttypesofflames:safetyflame,blueflame,androaringblueflame.

1.Safety flame –Itisyellowororangeincolor.Itisthecoolestflame,approximately300°C.Itistheflameproducedwhenairholesareclosed.ItisusedonlytoshowthattheBunsenburnerisonandnotforheating.

2. Blue flame –Itisalsocalledmediumflame,nonluminousflame,orinvisibleflame.Itisapproximately500°C.Itisthemostcommonlyusedflame.

3.Roaring blue flame–Itisthehottestflame,approximately700°C.Itischaracterizedbyalightbluetriangleinthemiddle.Itisso-namedbecauseitmakesaroaringsound.

ThecorrectstepsinsettingupandoperatingtheBunsenburnersafelyandappropriatelyareasfollows:

1.ConnecttheBunsenburnertothegassupplyusingarubbertubing.2.Completelyclosetheairholes.3.Turnthegasvalveonthegasoutlettothefullyopenposition.4.Lighttheburnerbyholdingamatchtothesideofthemouthoftheburner.Ifyoustickthe

matchinthemiddleofthegasstream,theflameisusuallyblownoutbeforetheburnerlights.5.Opentheairholesslowlytoadmitmoreairintotheflameandproducealightblueflame.

Adjusttheairholesandgassupplytoproducethedesiredsizeofflame.6.Turntheburneroffatthemaingassupplyvalvewhendone.

Heating Solids and Liquids1.Solids

Toheatsolidsinatesttube,clampthetubetoanironstandat45°.Theflameispassedslowlybackandforthalongthebottomofthetube.Solidsmaybeheatedtohightemperaturesinacruciblesupportedbyaclaytriangleoveranironringortripod.Thecrucibleiscarefullyplacedonaclaytriangleeitheratuprightpositionoratacertainangle.

2.Liquids Whenheatingliquidsinabeaker,placeitoverawiregauzesupportedbyanironringattachedtoanironstand.Thewiregauzedistributestheheatevenlyandpreventscrackingofthecontainerduetosuddentemperaturechanges.Duringheating,stirtheliquidwhilecarefullyheatingtoavoidlumping.Unevenboilingcancausethedangerousspatteringoflargequantitiesofhotliquid.

barrel

gas inlet

base

air hole


Whenheatingliquidsinatesttube,holdthetubewithatesttubeholderat45°andpassitbackandforthovertheflameofaburner.Thetesttubeshouldbeheatedjustbelowtheliquidlevel,butneveratthebottomofthetube.(Note: Heatthetubewiththeopenendpointedawayfromyouandfromanyoneelse.Neverheatthetubedirectlyatthebottom,thecontentsmaybeejectedsuddenlyduetosuperheating.Neverboilaliquidinatube,whichismorethanaquarterfull.)

Measuring Mass The balance isaninstrumentusedfordeterminingthemassofasubstance.Amongthevarioustypesoflaboratorybalances,themostcommonlyusedisthetriplebeambalance,althoughtop-loadingdigitalbalancesarebecomingpopular. Incarryingthebalance,placeonehandunderthebaseandtheotherhandonthearm.Besurethatallridersarebacktothezeropoint. Tomeasurethemassofasubstance,thepointermustbeatthezeroscale.Putallridersatthezeropoint.Ifthepointerisnotinexactbalance,usetheadjustmentscrewtopointitbacktothezeromark.Neverputchemicalsdirectlyonthebalancepan.Useapaperboxoracleananddryemptycontainer.Getthemassofthepaperboxorcontainerbeforeaddingthechemicals.Onceyouhaveplacedtheobjecttobeweighedonthepan,movetheridersalongthebeamsbeginningwiththelargestmassfirst.Makesureallridersareinanotchbeforeyoutakeareading.Returnalltheriderstozeropointafterweighing.Alwayskeepthebalanceclean.

CSI

adjustment screw

beams

base

panriders

Creating a Paper Box

(1)

(2)

arm

3. Foldthefourcornersinward,butdonotexceedthelinesfromthesecondfoldinstep2.Makesurenottofoldinmorethanathirdofthewidth.

(3)

1. Foldthepaperinhalf,thenextenditbackout.Foldeachhalfinwardagaintoendupinthemiddleline.

2. Turnthepapersidewaysandrepeatstep1.However,afterthesecondfold,foldbackout

againandstraightenthepaper.


4. Foldtheedgesonthemiddlelineoutoverthetriangles

madeinstep3inastraightline.

5. Pulloutslowlybothsidesoverthemiddleline,strengtheningtheedgesandcornersasyouproceed. Makesurethatthecornersarestrongandforming90°.

Using the Platform BalanceObjectives: 1.Manipulatetheplatformbalancecorrectly.2.Comparethemassofacupofsandwithacupofsalt.

Materials: platformbalance,salt,sand,measuringcup,setofweights

Procedure:1. Usethepaperboxyoumade.Placeitontheleftpanoftheplatformbalance.Determinethe

massofthepaperboxbymovingtheridersuntilthepointerreachesthepoint.Recordthemassinthedatatable.

2. Put1cupofsandinthepaperbox.Bringthepointertothezeromark.Recordthemassinthedatatable.

3.Makeanotherpaperboxanddetermineitsmass.Recordthemassinthedatatable.4. Put1cupofsaltinthepaperboxanddetermineitsmass.Recordthemassinthedatatable.

Questions: 1. Whyshouldyoudeterminetherestpointofaplatformbalancebeforegettingthemassofa

sample?2. Whatarethepossiblecausesoferrorinweighing?3. Whichisheavier:acupofsaltoracupofsand?Why?

Data TableSand Salt

MassofpaperboxMassofpaperbox+sampleMassofsample

(4)

(5)

Discover Science: Chemistry�0

Chapter Test

Choosetheletterofthecorrectanswer.

Fornumbers1–3,refertothechoicesbelow: a.beaker b.crucibleandcover c.graduatedcylinder d.testtube

1. Itisadeep,wide-mouthed,thin-walled,andcylindricaldevicewithaspout.

2. Itisacontainermadeofporcelainandisusedforheatingsubstancesthatrequiresextremeheat.

3. Itisaglasstubeclosedatoneendandisusedintestingchemicals.

Fornumbers4–5,refertothechoicesbelow: a.blackmagic b.alchemy c.traditionalchemistry d.modernchemistry

4.Duringthisperiod,peoplebelievedthatleadcanbetransmutedintogold.

5.Duringthisperiod,peoplebelievedinthefourelements:fire,earth,water,andair.

6.Whichofthefollowingis notaqualitativeobservation?a.Theredroseiswiltingslowly.b.Thestemoftherosehasmanythorns.c.Thestemoftheroseis25centimeterslong.d.Therosehasasweetscentthatfillstheroom.

7.Whichofthefollowingisnotanintegrationofchemistryandinformationtechnology?a. Databaseforallchemicalsfoundintheworldb. Increasedsalesamongallkindsofconsumersc. Higherresistanceofcomputerstoheatandforced. Cheaperrawmaterialsthatcanbeusedformakingmicrochips

8.Whichofthefollowingisnotcorrect?a.biochemistry:livingorganismb.inorganicchemistry:carboncontainingcompoundsc.physicalchemistry:propertiesofmatterd.polymerchemistry:plastics

9.WhichofthefollowingisnotacontributionofAntoineLaurentLavoisier?a.disproofofthephlogistontheoryb.metricsystemc.The Skeptical Chemistd.lawofconservationofmass

The Building Block of Science �1

10.WhodiscoveredPrialt,apainrelieverderivedfromconesnails?a. AmandoKapauan c.BaldomeroOliverab.AnacletodelRosario d.JulianBanzon

Fornumbers11–12,refertothehypothesisbelow:

Ifcologneisnotcovered,itwillevaporate.

11.Whichsetofmaterialscanbeusedtotestthehypothesis?a.ContainerAisfilledwithcologneandiscovered;containerBisemptyanduncovered.b.ContainersAandBareeachfilledwiththesameamountoforequalvolumeofcologne;one

iscoveredandtheotheroneisuncovered.c.ContainersAandBarefilledwithcologne;botharecovered.d.ContainersAandBarefilledwithcologne;bothareuncovered.

12.Whatisthedependentvariable?a.beakersb.brandofcolognec.exposuretoaird.volumeofcologne

13.Whatisthefirstthingthatyouwilldowhenanacidisspilledonyourhand?a.Gotothehospital.b.Informyourparentabouttheaccident.c.Washyourhandwithplentyofwater.d.Applyburntointmentandcoveritwithgauze.

14.Whencarryingoutexperimentsinthelaboratory,whichofthefollowingshouldnotbedone?a.makingobservationsb.tastingchemicalsc. takingmeasurementsd.recordingdata

15.WhenyoulittheBunsenburner,abeakerwithalcoholsuddenlycatchesfire.Whatwillyoudo?a.Turnonthefirealarm.b.QuicklyturnofftheBunsenburner.Then,smotherthebeakerwithdamptowel.c.Callthefiredepartment.d.Callthepolice.


Science Cares

WritealetterexpressingyourideasontheneedofFilipinochemistsandscientistsingeneraltobegivenpublicrecognition.Theaimofyourletteristoacknowledgethesignificantroleofchemistsinthesociety.Sendittotheeditorofanynotablenewspaper.Includethefollowinginyourletter:1. thehardshipsandproblemsthatFilipinoscientistsexperience;2. theimportanceofgivingscientistspublicrecognitioninordertogivetheyouthandother

Filipinosasourceofinspirationandnationalpride;and3. theneedformoreFilipinoscientistsinthefuture.

Performance Tasks

1. Youareanagriculturalchemist.Youhavebeeninvitedbythefarmersinyourcommunitytohelpthemproducebettercrops.Youwillgiveashorttalktothefarmerstosharesomeinnovativewaysoffarming.Yourtalkmustbesimpleyetinformative.

2. Youareanewlyhiredlaboratorytechnicianinaschool.Youareassignedtomakeahandbookontheproperuseofthelaboratory.Yourhandbookmustincludebasiclaboratoryrulesandalistofthedifferentapparatusfoundinyourschoollaboratoryandtheiruses.Yourhandbookmustbescientificallyaccurate,freefromspellingandgrammaticalerrors,andvisuallyappealing.

3. Youareatechnologyenthusiast.Yourtaskistodesignausefultechnologythatwillhelppeopleintheirdailylives.Usethefollowingformatindesigningyourtechnology:

• Nameoftechnology• Use(s)• Compositionofmaterials• Mechanism(howthetechnologyworks)• Illustrationofyourtechnology(showitsdimensions)• Explainthesignificanceofyournewtechnologytochemistryandthesociety

Makesurethatyouroutputiscompleteandaccurate.