Chapter 1: Introduction to Chemistry - irion-isd.org...2 Chapter 1 Introduction to Chemistry CHAPTER...

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Section 1.2Chemistry and Matter1/2 session

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1. Explain the formation and importanceof ozone.

2. Describe the development ofchlorofluorocarbons.

3. Define chemistry and matter.4. Compare and contrast mass and

weight.5. Explain why chemists are interested in

a submicroscopic description of matter.

6. Identify the common steps ofscientific methods.

7. Compare and contrast types of data.8. Compare and contrast types of

variables.9. Describe the difference between a

theory and a scientific law.

Discovery Lab: Where is it? p. 3

Problem-Solving Lab: Chemical Models,p. 8Careers Using Chemistry: ChemistryTeacher, p. 9

ChemLab: The Rubber Band Stretch,pp. 18–19

Section 1.4Scientific Research1 session

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10. Compare and contrast pure research,applied research, and technology.

11. Apply knowledge of laboratory safety.

MiniLab: Developing Observation Skills,p. 15Chemistry and Society: The HumanGenome Project, p. 20

Section Objectives Activities/Features

Section 1.1The Stories of TwoChemicals1/2 session

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CHAPTER Introduction to Chemistry

National Science State/Local Reproducible Masters TransparenciesContent Standards Standards

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CHAPTER 1 RESOURCE MANAGER

UCP.1, UCP.2; A.1, A.2;B.3, B.6; E.2; F.4, F.5, F.6;G.2, G.3

1(A), 2(E), 3(C), 3(E),5(A)

UCP.1, UCP.2; A.1; B.2;G.1, G.2

3(D), 4(A), 4(C)

UCP.1, UCP.2; A.2; G.1,G.2

3(A), 3(C), 3(E)

UCP.1, UCP.2; A.1, A.2;B.2, B.6; E.2; F.1, F.4, F.6;G.1, G.2, G.3

1(A), 2(A), 2(B), 2(D),2(E), 3(A), 3(C), 3(E),4(A), 5(A), 5(C)

Study Guide for Content Mastery,pp. 4–5 ChemLab and MiniLabWorksheets, pp. 2–4 CBL Laboratory Manual, pp. 1–4L2

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Section Focus Transparency 3

Teaching Transparency 2

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Study Guide for Content Mastery,p. 6 ChemLab and MiniLabWorksheets, p. 1 Laboratory Manual, pp. 1-4,5–8 L2

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Study Guide for Content Mastery,p. 1 Challenge Problems, p. 1 L3

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Study Guide for Content Mastery,pp. 2–3 L2

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Key to National Science Content Standards: UCP � Unifying Concepts andProcesses, A � Science as Inquiry, B � Physical Science, C � Life Science,D � Earth and Space Sciences, E � Science and Technology,F � Science in Personal and Social Perspectives, G � History and Nature of Science

Refer to pages 4T–5T of the Teacher Guide for an explanation of the National Science Content Standards correlations.

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ChemLab (pages 18–19)large rubber band, 500-g mass, ring stand, clamp, hair dryer, meterstick

Discovery Lab (page 3)large kitchen matches, laboratory balance, stopwatch or clock

MiniLab (page 15)petri dish (2), 25-mL graduated cylinder, whole milk, water, vegetable oil, food coloring (4 different colors), toothpicks (2), dishwashing detergent

Demonstration (pages 10–11)0.05 g potassium permanganate (KMnO4), 1 g sodium hydrogen sulfite (NaHSO3), 1 g bariumchloride dihydrate (BaCl2�2H2O), 400-mL beakers (3), small test tubes (2), water

For a review of solution preparation, see page 46T of the Teacher Guide.

Quantities are for a class of 30 students.

Demonstration (pages 10–11)potassium permanganate solution Dissolve 3 or 4 small crystals, about 0.05 gram, of

potassium permanganate (KMnO4) in 250 mL water. CAUTION: The solution is toxic.barium chloride solution Add 1 gram of barium chloride dihydrate (BaCl2�2H2O) to 1 mL

water in a small test tube. CAUTION: The solution is toxic.sodium hydrogen sulfite solution Add 1 gram sodium hydrogen sulfite (NaHSO3) to 1 mL

water in a small test tube. CAUTION: The solution is toxic.

Materials List

Preparation of Solutions

CHAPTER Introduction to Chemistry1

Resource Manager

Chapter Assessment, pp. 1–6MindJogger VideoquizzesAlternate Assessment in the Science ClassroomTestCheck Software Solutions Manual, Chapter 1Supplemental Problems, Chapter 1Performance Assessment in the Science ClassroomChemistry Interactive CD-ROM, Chapter 1 quiz

Spanish Resources Guided Reading Audio Program, Chapter 1Cooperative Learning in the Science ClassroomLab and Safety Skills in the Science ClassroomLesson PlansBlock Scheduling Lesson Plans

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Assessment Resources Additional Resources

Texas Lesson PlansTexas Block Scheduling Lesson Plans

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Level 1 activities should be appropriate for students withlearning difficulties.

Level 2 activities should be within the ability range of all students.

Level 3 activities are designed for above-average students.

ELL activities should be within the ability range ofEnglish Language Learners.

Cooperative Learning activities are designedfor small group work.

These strategies represent student products that can beplaced into a best-work portfolio.

These strategies are useful in a block scheduling format.

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VIDEOTAPE/DVDMindJogger Videoquizzes,Chapter 1

VIDEODISCCosmic ChemistryGreenhouse Effect, MovieOzone Studies, MovieNylon, MovieDr. Jekyll and Mr. Hyde, MovieLab Safety, Movie

CD-ROMChemistry: Matter and ChangeMagic of Chemistry, Demonstration

The following multimedia for this chapter are available from Glencoe.

Look for the following icons for strategies that emphasize different learning modalities.KinestheticMeeting Individual Needs, pp. 5, 7

Visual-SpatialReteach, pp. 5, 9; Portfolio, p. 16

InterpersonalMeeting Individual Needs, p. 15; Reinforcement,

p. 16

IntrapersonalChemistry Journal, pp. 5, 12, 14; Extension, p. 11;

Meeting Individual Needs, p. 12

LinguisticChemistry Journal, p. 8

Logical-MathematicalQuick Demo, p. 10

Key to Teaching Strategies

Glencoe Technology

Multiple Learning Styles

CHAPTER 1 RESOURCE MANAGER

Assessment Planner

Portfolio AssessmentPortfolio, TWE, p. 16Assessment, TWE, pp. 4, 17

Performance AssessmentAssessment, TWE, p. 13Problem-Solving Lab,TWE, p. 8

ChemLab, TWE, p. 19MiniLab, SE, p. 15MiniLab, TWE, p. 15Demonstration, TWE, p. 11ChemLab, SE, pp. 18–19Discovery Lab, SE, p. 3

Knowledge AssessmentAssessment, TWE, pp. 6, 9Section Assessment, SE, pp. 6,9, 13, 17

Chapter Assessment, SE,pp. 22–23

Skill AssessmentAssessment, TWE, p. 11

2 Chapter 1

Introduction toChemistry

CHAPTER 1

Visit the Chemistry Web site atscience.glencoe.com to findlinks about chemistry and matter.

The four nebulae shown herecontain a stew of elements. Thered color in two of the nebulae isemitted by hydrogen atoms. TheHorsehead Nebula can be seen onthe right. The fourth nebula isthe bluish structure below thehorse’s head. The round, brightobject on the left is the star, ZetaOrionis.

What You’ll LearnYou will describe the rela-tionship between chemistryand matter.

You will recognize how sci-entific methods can be usedto solve problems.

You will distinguishbetween scientific researchand technology.

Why It’s ImportantYou, and all the objectsaround you, are composedof matter. By studyingmatter and the way itchanges, you will gain anunderstanding of your bodyand all the “stuff” you seeand interact with in youreveryday life.

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1CHAPTER

Using the Photo Ask students what is involvedwhen a star explodes. Lead them tounderstand that the event involvesmatter and energy and how theyinteract. Tell them that this inter-action is what chemistry is allabout—matter and energy and howthey relate to each other.

Chapter ThemesThe following themes from theNational Science EducationStandards are covered in thischapter. Refer to page 4T of theTeacher Guide for an explanationof the correlations.Systems, order, and organization(UCP.1)Evidence, models, and explanation(UCP.2)Change, constancy, andmeasurement (UCP.3)

Pages 2–31(A), 2(E)

DISCOVERY LAB

Purpose Students will observe a chemical reactionand relate their observations to defini-tions of matter and chemistry.

Safety and DisposalCaution students to use care around anopen flame. Have them place usedmatches in a flameproof container or ina container of water.

Teaching Strategies• Ask students what evidence they

observe that a change in matter istaking place. Answers might includechange in appearance or odor or agas and energy are given off.

• Use the odor produced by this experi-ment to introduce a discussion of airpollution. This lab can be used to intro-duce the ozone problem discussed inthis chapter.

Expected Results The match loses mass in each trial. Thedata from trial 1 should agree closelywith the data from trial 2.

AnalysisThe change in mass occurs because solidsare changed into the gases that arereleased during the reaction.

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1.1Section

1 Focus

Before presenting the lesson, displaySection Focus Transparency 1on the overhead projector and havestudents answer the accompanyingquestions using Section FocusTransparency Master 1.

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Focus Transparency

1.1 The Stories of Two Chemicals 3

DISCOVERY LAB

Materials

large kitchen matcheslaboratory balancelab notebookpenstopwatch or clock

Where is it?

When an object burns, the quantity of ashes that remain is smallerthan the original object that was burned. What happened to the

rest of the object?

Safety Precautions

Procedure

1. Measure the mass of a large kitchen match. Record this measure-ment and detailed observations about the match.

2. Carefully strike the match and allow it to burn for five seconds.Then, blow it out. CAUTION: Keep hair and loose clothing awayfrom the flame. Record observations about the match as it burnsand after the flame is extinguished.

3. Allow the match to cool. Measure and record the mass of theburned match.

4. Place the burned match in a container designated by your instructor.

5. Repeat this procedure. Compare your data from the two trials.

Analysis

How do you account for the change in mass? Where is the matterthat appears to have been lost?

Do not place matches in the sink. Use cautionaround flames.

Objectives• Explain the formation and

importance of ozone.

• Describe the developmentof chlorofluorocarbons.

Section 1.1 The Stories of Two Chemicals

Take a moment to look around you. Where did all the “stuff” you see comefrom? All the stuff in the universe is made from building blocks formed instars such as the ones shown in the photo on the opposite page. And, as youlearned in the DISCOVERY LAB, this stuff changes form.

Scientists are naturally curious. They continually ask questions about andseek answers to all that they observe in the universe. One of the areas in whichscientists work is the branch of science called chemistry. Your introductionto chemistry will begin with two unrelated discoveries that now form the basisof one of the most important environmental issues of our time.

The Ozone LayerYou are probably aware of some of the damaging effects of ultraviolet radi-ation from the Sun if you have ever suffered from a sunburn. Overexposureto ultraviolet radiation also is harmful to plants and animals, lowering cropyields and disrupting food chains. Living things can exist on Earth becauseozone, a chemical in Earth’s atmosphere, absorbs most of this radiation beforeit reaches Earth’s surface. A chemical is any substance that has a definite com-position. Ozone is a substance that consists of three particles of oxygen.

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Section Focus Transparency 1 Protection from the SunUse with Chapter 1, Section 1.1

Chemistry: Matter and Change

Section Focus Transparencies

How are these people protecting themselves from the Sun?

Why is this protection necessary?

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Quick Demo

Demonstrate thatchemicals are everywhere. Burn a candle in the front of theclassroom. Explain that the waxin the candle is a chemical, as isthe oxygen in the air needed to burn the wax. If you holdyour hand too close to theflame, the flame will burn thechemicals that form your skin.UV light from the sun can alsoburn your skin. Sunscreencontains chemicals that absorbUV light before it reaches yourskin. Ozone is a chemical in theair that absorbs UV light beforeit reaches Earth’s surface.

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Study Guide for Content Mastery,p. 1

Solving Problems: A Chemistry Handbook, Section 1.1

Section Focus Transparency 1 and Master

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Earth’s atmosphere As you can see in Figure 1-1, Earth’s atmosphere con-sists of layers. The lowest layer is called the troposphere and contains the airwe breathe. The troposphere is where the clouds shown in Figure 1-2 occurand where airplanes fly. All of Earth’s weather occurs in the troposphere.

The stratosphere is the layer above the troposphere. It extends from about15 to 50 kilometers (km) above Earth’s surface. The ozone that protects Earthis located in the stratosphere. About 90% of Earth’s ozone is spread out in alayer that surrounds and protects our planet.

Ozone formation How does ozone enter the stratosphere? Ozone is formedwhen oxygen gas is exposed to ultraviolet radiation in the upper regions ofthe stratosphere. Particles of oxygen gas are made of two smaller oxygen par-ticles. The energy of the radiation breaks the gas particles into oxygen parti-cles, which then interact with oxygen gas to form ozone. Figure 1-3 illustratesthis process. Ozone also can absorb radiation and break apart to reform oxy-gen gas. Thus, there tends to be a balance between oxygen gas and ozone lev-els in the stratosphere.

Ozone was first identified and measured in the late 1800s, so its presencehas been studied for a long time. It was of interest to scientists because aircurrents in the stratosphere move ozone around Earth. Ozone forms over theequator where the rays of sunlight are the strongest and then flows towardthe poles. Thus, ozone makes a convenient marker to follow the flow of airin the stratosphere.

In the 1920s, G.M.B. Dobson began measuring the amount of ozone in theatmosphere. Although ozone is formed in the higher regions of the stratosphere,most of it is stored in the lower stratosphere, where it can be measured byinstruments on the ground or in balloons, satellites, and rockets. Dobson meas-ured levels of stratospheric ozone of more than 300 Dobson units (DU). Hismeasurements serve as a basis for comparison with recent measurements.

During 1981–1983, a research group from the British Antarctic Survey wasmonitoring the atmosphere above Antarctica. They measured surprisingly lowlevels of ozone, readings as low as 160 DU, especially during the Antarcticspring in October. They checked their instruments and repeated their measure-ments. In October 1985, they reported a confirmed decrease in the amount ofozone in the stratosphere and concluded that the ozone layer was thinning.

4 Chapter 1 Introduction to Chemistry

Figure 1-1

Earth’s atmosphere consists ofseveral layers. The layer nearestEarth is the troposphere. Thestratosphere is above the troposphere.

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The troposphere extends to a height of about 15 km.Cumulonimbus clouds, or thun-derheads, produce thunder,lightning, and rain.

Portfolio Have studentsdraw the layers of the atmosphereand indicate where ozone is formedand stored. Drawings can be placedin student portfolios. PP

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AssessmentAssessment

ReinforcementAsk students why the majority ofozone would be formed over theequator. Ozone formation in thestratosphere depends on theenergy from UV rays from thesun striking and breaking upoxygen. The direct rays at theequator have more energy thanthe slanted rays that strike otherparts of Earth.

Quick Demo

Bring in a globe andan electric lamp. Ask studentsto identify the equator, whereozone is produced in thegreatest quantity. Showstudents how the light raysstrike Earth directly at theequator. Have a student volun-teer confirm that more energyis felt where light rays strikedirectly than where they strikeat an angle. Also show howconvection currents caused byunequal heating of the atmo-sphere flow ozone from theequator to the poles.

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Skin TonesDarker skin tones offer more protection fromharmful UV rays in sunlight. Therefore, whererays from the sun are strong near the equa-tor, skin tones have evolved to be darker. UVrays are less intense in areas farther from theequator, so skin tones are lighter there.

Although the Inuit people live far north ofthe equator, their skin tones are darker thanwould be expected because snow reflects UVlight. The Inuit need darker skin to protectthem from the increased levels of UV lightthey receive from reflection.

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VIDEODISCCosmic ChemistryDisc 4, Side 8

Movie: Greenhouse Effect 1:00 minExamination of this climaticchemical phenomenon

{bs`eQa”}Movie: Ozone Studies 1:17 minChemical changes in the ozonelayer

{bPTcq¡◊}

Figure 1-4

The thinning heel of thissock models the thinning of theozone layer in the stratosphere.

This colored satellite map ofstratospheric ozone overAntarctica was taken onSeptember 15, 1999. The lowestamount of ozone (light purple)appears over Antarctica (darkpurple). Blue, green, orange,and yellow show increasingamounts of ozone.

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Although the thinning of the ozone layer is often called the ozone hole, itis not actually a hole. You can think of it as being similar to the old sock inFigure 1-4a in which the material of the heel is wearing thin. You might beable to see your skin through the thinning sock. So although the ozone is stillpresent in the atmosphere, the protective layer is much thinner than normal.This fact has alarmed scientists who never expected to find such low levels.Measurements made from balloons, high-altitude planes, and satellites havesupported the measurements made from the ground, as the satellite map inFigure 1-4b shows. What could be causing the ozone hole?

ChlorofluorocarbonsThe story of the second chemical in this chapter begins in the 1920s.Refrigerators, which used toxic gases such as ammonia as coolants, were justbeginning to be produced large scale. Because ammonia fumes could escapefrom the refrigerator and harm the members of a household, chemists beganto search for safer coolants. Thomas Midgley, Jr. synthesized the first chlo-rofluorocarbons in 1928. A chlorofluorocarbon (CFC) is a chemical that con-sists of chlorine, fluorine, and carbon. There are several different chemicalsthat are classified as CFCs. They are all made in the laboratory and do notoccur naturally. CFCs are nontoxic and stable. They do not readily react withother chemicals. At the time, they seemed to be ideal coolants for refrigera-tors. By 1935, the first self-contained home air-conditioning units and eightmillion new refrigerators in the United States used CFCs as coolants. In addi-tion to their use as refrigerants, CFCs alsowere used in plastic foams and as propellantsin spray cans.

1.1 The Stories of Two Chemicals 5

Figure 1-3

This model of the formation ofozone shows that ultravioletradiation from the Sun causesoxygen gas to break down intotwo individual particles of oxy-gen. These individual oxygenparticles combine with oxygengas to form ozone, which con-sists of three oxygen particles.

Oxygen gas

Formation of ozone

Ozone

Ultravioletradiation

Go to the Chemistry Interactive CD-ROM to find additionalresources for this chapter.

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Concept DevelopmentHave a local mechanic or air condi-tioning specialist speak to the classon the safeguards that currentlyexist to keep harmful chemicalsfrom affecting the atmosphere. Askhim or her to clarify that chemicalsthat are shown to be harmful to theenvironment can be either elimi-nated or replaced with a chemicalthat is less harmful.

DiscussionAsk students what comes to mindwhen the term chemical is used.Often, the term has a negativeconnotation. Emphasize that chem-icals are all around them and thatthey could not exist without them.Some chemicals can be harmful,but others are not only helpful, butessential.

3 AssessCheck for UnderstandingWhat is the normal level of ozonein the stratosphere? 300 DU Whatwas the lowest level that scientistsfound over the Antarctic in theearly 1980s? 160 DU Have studentsexplain why scientists werealarmed at these findings.

ReteachVisual-Spatial Bring in athin sock or item of clothing.

Demonstrate that the material isstill present, but it is thinner thannormal and allows more light topass through. Have studentsexplain how this model is similarto the ozone hole.

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Pages 4–53(C), 3(E), 5(A)


Challenge Problems, p. 1 Teaching Transparency 1 and Master

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CHEMISTRY JOURNAL CHEMISTRY JOURNAL

Thomas MidgelyIntrapersonal Have studentsresearch for information on Thomas

Midgely, Jr. Then, have them write a shortsummary on why he created CFCs. P

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MEETING INDIVIDUAL NEEDS MEETING INDIVIDUAL NEEDS

Visually Impaired Kinesthetic Have sighted studentswork with visually impaired students

to create a three-dimensional, tactilemodel of layers of the atmosphere. Havethe sighted student explain the location ofthe troposphere and stratosphere andozone formation and storage. P

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Now think of all the refrigerators in yourneighborhood, in your city, across the coun-try, and around the world. Think of the airconditioners in homes, schools, office build-ings, and cars that also used CFCs. Add toyour mental list all of the aerosol cans andplastic foam cups and food containers usedeach day throughout the world. If all of theseproducts contained or were made with CFCs,imagine the quantities of these chemicals thatcould be released into the environment in asingle day.

Scientists first began to notice the pres-ence of CFCs in the atmosphere in the 1970s.They decided to measure the amount of CFCsin the stratosphere and found that quantitiesin the stratosphere increased year after year.This increase is shown in Figure 1-5. But, itwas thought that CFCs did not pose a threatto the environment because they are so stable.

Two separate occurrences had been noticedand measured: the protective ozone layer in the atmosphere was thinning, andincreasingly large quantities of useful CFCs were drifting into the atmo-sphere. Could there be a connection between the two occurrences? Before youlearn the answer to this question, you need to understand some of the basicideas of chemistry and know how chemists—and most scientists, for that matter—solve problems.


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Section 1.1 Assessment

1. Why is ozone important in the atmosphere?

2. Where is ozone formed and stored?

3. What are CFCs? How are they used?

4. Thinking Critically Why do you think ozone isformed over the equator? What is the connectionbetween sunlight and ozone formation?

5. Comparing and Contrasting What generaltrend in ozone concentration is shown in the graphat the right? How does the data for the years1977–1987 on this graph compare to the sametime span on the graph in Figure 1-5? What doyou notice?

Figure 1-5

Quantities of CFCs in the atmo-sphere continued to rise until aban on products containingthem went into effect in manycountries.

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ExtensionDiscuss with students how theprocesses used to manufactureproducts change over time. Includein the discussion the role chemistryhas in these changes. Mention the evolution of refrigerants asdiscussed in the text. Bring to classa cardboard milk container and aplastic milk jug. Ask students todescribe the benefits and disadvan-tages of each type of container. Thecardboard will decompose overtime; the plastic will not. Bothcan be recycled. Milk will stayfresher in the plastic.

Knowledge Providestudents with two lists. One listcontains the layers of the atmo-sphere, listed in random order. Theother list contains one character-istic of each layer. The characteris-tics should relate to the chemistryof the layer. Ask students to matcheach layer to its characteristic. L2

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Pages 6–73(C), 3(E), 4(C)

Section Assessment1.1

1. Ozone absorbs harmful UV light fromthe sun, preventing it from reachingEarth’s surface where it could damageliving organisms.

2. in the stratosphere3. chlorofluorocarbons; refrigerants, in

foams, propellants in spray cans

4. Sunlight provides energy needed forozone formation. Sunlight is moreintense at the equator, so more ozoneforms.

5. Ozone levels are decreasing. As CFCsincrease, ozone concentration decreases.

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1.2Section

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Objectives• Define chemistry and

matter.

• Compare and contrast massand weight.

• Explain why chemists areinterested in a submicro-scopic description of matter.

Vocabularychemistrymattermassweight

Section Chemistry and Matter

Matter, the stuff of the universe, has many different forms. You are made ofmatter. There is matter in the bed, blankets, and sheets on which you sleep aswell as in the clothes you wear. There is matter in the food you eat, and inmedications and vitamins you may take. You have learned that ozone is a chem-ical that occurs naturally in the environment, whereas CFCs do not. Althoughboth chemicals are invisible gases, they, too, are matter.

Chemistry: The Central ScienceChemistry is the study of matter and the changes that it undergoes. A basicunderstanding of chemistry is central to all sciences—biology, physics, Earthscience, ecology, and others. Chemistry also is central to our everyday lives,as Figure 1-6 illustrates. It will continue to be central to discoveries made inscience and technology in the twenty-first century.

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Figure 1-6

High-tech fabrics that don’t hinder athletic performance,water, fertilizers, pesticides,food, grocery items, clothing,building materials, hair careproducts, plastics, and even thehuman body are made of chemicals.

1.2 Chemistry and Matter 7

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Section Focus Transparency 2 Weight and MassUse with Chapter 1, Section 1.2



Do you think this astronaut weighs more, less, or the same

on the Moon as he weighs on Earth?Do you think this astronaut’s mass is more, less, or the

same on the Moon as it is on Earth?

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Quick Demo

Light the candleused in the Quick Demo onpage 3. Discuss the burning ofthe candle in terms of matter.Chemistry involves the study of the composition of matter,such as the wax in the candleand the oxygen in the air, andchanges in matter, such as thechanges that occur in the waxas it burns.

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Visually Impaired Kinesthetic Have visually impairedstudents choose several objects, such

as their textbooks, and describe them.Characteristics may include that they haveweight and shape. Help students see theseproperties as mass and volume. Blow up aballoon. Have students touch it to “feel”the mass and volume of air contained inthe balloon.

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Matter and its CharacteristicsYou recognize matter in the everyday objects you are familiar with, such asthose shown in Figure 1-6. But, how do you define matter? Matter is any-thing that has mass and takes up space. Mass is a measurement that reflectsthe amount of matter. It is easy to see that your textbook has mass and takesup space. Is air matter? You can’t see it and you can’t always feel it. However,when you inflate a balloon, it expands to make room for the air. The balloongets heavier. Thus, air must be matter. Is everything made of matter? Thethoughts and ideas that “fill” your head are not matter; neither are heat, light,radio waves, nor magnetic fields. What else can you name that is not matter?

Mass and weight When you go to the supermarket to buy a pound of veg-etables, you place them on a scale like the one shown in Figure 1-7 to findtheir weight. Weight is a measure not only of the amount of matter but alsoof the effect of Earth’s gravitational pull on that matter. This force is notexactly the same everywhere on Earth and actually becomes less as you moveaway from Earth’s surface at sea level. You may not notice a difference in theweight of a pound of vegetables from one place to another, but subtle differ-ences do exist.

It might seem more convenient for scientists to simply use weight insteadof mass. You might wonder why it is so important to think of matter in termsof mass. Scientists need to be able to compare the measurements that theymake in different parts of the world. They could identify the gravitational forceevery time they weigh something but that is not practical or convenient. Thisis why they use mass as a way to measure matter independent of gravitationalforce.

What you see and what you don’t What can you observe about the out-side of your school building or a skyscraper downtown? You know that thereis more than meets the eye to such a building. There are beams inside the wallsthat give the building structure, stability, and function. Consider another


problem-solving LAB

Chemical ModelsMaking Models Until the mid-1980s, scientiststhought there were only two forms of carbon,each with a unique structure: diamond andgraphite. As with many scientific discoveries,another form of carbon came as a surprise.

Buckminsterfullerene, also called the bucky-ball, was found while researching interstellarmatter. Scientists worked with various models ofcarbon structures until they determined that 60carbons were most stable when joined togetherin a shape that resembles a soccer ball.

AnalysisExamine the structure in the diagram. Where arethe carbon atoms? How many carbons is eachcarbon connected to? Identify the pentagons andhexagons on the faces on the buckyball.

Thinking CriticallyGo back to Figure 1-3 to see an example ofanother model that chemists use. What processdoes the figure show? Explain why this informa-tion could not be shown in a photograph. Whatdo the colored particles represent? Use Table C-1in Appendix C to help you in your identification.

Figure 1-7

A scale measures the downwardpull of gravity on an object. Ifthis scale were used on theMoon, the reading would be lessthan on Earth.

8

Purpose Students will examine, compare,and analyze scientific models.

Process SkillsUsing scientific illustrations,observing and inferring, comparingand contrasting

Teaching StrategiesBring a soccer ball to class andhave students compare the patternshown on it to the structure of abuckyball.

AnalysisThe carbon atoms are on theoutside of the molecule. Eachcarbon atom is connected tothree other carbon atoms.

Thinking CriticallyThe figure shows the formationof ozone from oxygen. The parti-cles are too small and the processtoo fast to be shown in a photo-graph. The colored particlesrepresent oxygen atoms.

Performance Have mo-lecular model kits or gumdrops andtoothpicks available for interestedstudents to use to model molecules.Use the Performance TaskAssessment List for Model inPASC, p. 51.

3 AssessCheck for UnderstandingAsk students to define chemicaland chemistry. A chemical is anysubstance that has a definitecomposition. Chemicals make up matter. Chemistry is the studyof matter and the changes itundergoes.

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problem-solving LAB

In-Text Question Page 8 What else can you namethat is not made of matter?Answers might include feelings,emotions, microwaves, andsound.


WeightlessnessLinguistic Have students write abouthow they think they would feel to be

in an environment without gravity. Howwould lack of gravity affect their weight?Would they still fit the definition of mat-ter? Yes, they have mass and take upspace. Use this scenario to differentiatemass and weight.

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CD-ROMChemistry: Matter and ChangeDemonstration: Magic ofChemistry

example. When you bend your arm at the elbow, you observe that your handcomes toward your shoulder. Muscles that you cannot see under the skin con-tract and relax to move your arm.

Much of matter and its behavior is macroscopic; that is, you do not needa microscope to see it. You will learn in Chapter 3 that the tremendous vari-ety of stuff around you can be broken down into more than 100 types of mat-ter called elements, and that elements are made up of particles called atoms.Atoms are so tiny that they cannot be seen even with optical microscopes.Thus, atoms are submicroscopic. They are so small that 100 million millionmillion atoms could fit onto the period at the end of this sentence.

The structure, composition, and behavior of all matter can be explained ona submicroscopic level. All that we observe about matter depends on atomsand the changes they undergo. Chemistry seeks to explain the submicro-scopic events that lead to macroscopic observations. One way this can be doneis by making a model, a visual representation of a submicroscopic event.Figure 1-3 is such a model. The problem-solving Lab on the opposite pagegives you practice interpreting a simple chemical model.

Branches in the field of chemistry Because there are so many types ofmatter, there are many areas of study in the field of chemistry. Chemistry istraditionally broken down into the five branches listed in Table 1-1.

Additional areas of chemisty include theoretical chemistry, which focuseson why and how chemicals interact, and environmental chemistry, whichdeals with the role chemicals play in the environment.

1.2 Chemistry and Matter 9


6. Define matter.

7. Compare and contrast mass and weight.

8. Why does chemistry involve the study of thechanges in the world at a submicroscopic level?

9. Thinking Critically Explain why a scientist mustbe cautious when a new chemical that has manypotential uses is synthesized.

10. Using Numbers If your weight is 120 poundsand your mass is 54 kilograms, how would thosevalues change if you were on the moon? The grav-itational force on the moon is 1/6 the gravitationalforce on Earth.

Branches of Chemistry

Branch Area of emphasis Examples

Organic chemistry Most carbon-containing chemicals Pharmaceuticals, plastics

Inorganic chemistry In general, matter that does not contain Minerals, metals and nonmetals, semi-carbon conductors

Physical chemistry The behavior and changes of matter and Reaction rates, reaction mechanismsthe related energy changes

Analytical chemistry Components and composition of substances Food nutrients, quality control

Biochemistry Matter and processes of living organisms Metabolism, fermentation

Table 1-1

Chemistry TeacherDo you love chemistry? Wouldyou like to help others loveit—or at least understand it? Ifso, you might make an excel-lent chemistry teacher.

Chemistry teachers work inhigh schools and two-year andfour-year colleges. They lec-ture, guide discussions, conductexperiments, supervise labwork, and lead field trips. Highschool teachers might also beasked to monitor study hallsand serve on committees.College instructors might berequired to do research andpublish their findings.

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ReteachVisual-Spatial Bring toclass cubes of different

shapes, sizes, and materials. Youcould use wood, plastic, paper,and foam blocks. Ask students tocompare and contrast the blocks.Are they matter? Have them justifytheir answers. All are matterbecause they have mass and takeup space. They differ in that eachtype of block contains a differenttype and amount of matter.

Knowledge Ask studentswhere chemistry is used in theireveryday lives. Answers mightinclude the fuel used by theircars, heating their homes, theclothing they wear, and the foodthey eat. L2

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6. anything that has mass and volume7. Mass is a measure of the amount of

matter. It is independent of gravity.Weight is the effect of gravity on matter.

8. The changes you see with your eyes allbegin with changes at the submicro-scopic level.

9. Scientists might not be able to predict how a chemical may reactwith substances in its environment.

10. Your mass will still be 54 kg, but yourweight will be 1/6 your weight onEarth (120 lb/6 � 20 lb).

Career Path A careeras a chemistry teacherwould require collegecourses in both chemistryand education. Practical

experience in the classroom is also required.Career Issue Have studentsinvestigate the importance ofchoosing the right curriculummaterials when teaching chemistry.

For More Information For more information about careersin teaching chemistry, students cancontact

American Chemical Society Career Services1155 16th Street NWWashington, DC 20036

CAREERS USING CHEMISTRY

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1 Focus


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The Magic of Chemistry

Purpose Students observe that one substance can bechanged into another substance havingdifferent properties.

MaterialsKMnO4 (0.05 g); NaHSO3 (1 g); BaCl2 � 2H2O(1 g); 400–mL beakers (3); small test tubes (2)

Safety Precautions Disposal Filter the solution through filterpaper. Dispose of the solid in a landfillapproved to receive chemical waste.

ProcedureBefore the demo, dissolve three or four smallcrystals of KMnO4 in 250 mL of water in abeaker. In a test tube, add 1 g NaHSO3 to 1 mLof water. In a second test tube, add 1 g BaCl2 �2H2O to 1 mL of water. See page 2C for prepa-

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1.3Section

Focus Transparency

Section 1.3 Scientific Methods

Objectives• Identify the common steps

of scientific methods.

• Compare and contrast typesof data.

• Compare and contrast typesof variables.

• Describe the differencebetween a theory and a scientific law.

Vocabularyscientific methodqualitative dataquantitative datahypothesisexperimentindependent variabledependent variablecontrolconclusionmodeltheoryscientific law

Figure 1-8 shows students working together on an experiment in the labora-tory. You know that each person in the group probably has a different ideaabout how to do the project and a different part of the project that interestshim or her the most. Having many different ideas about how to solve a prob-lem is one of the benefits of many people working together. Communicatingideas effectively to one another and combining individual contributions toform a solution can be difficulties encountered in group work.

A Systematic ApproachScientists approach their work in a similar way. Each scientist tries to under-stand his or her world based on a personal point of view and individual cre-ativity. Often, the work of many scientists is combined in order to gain newinsight. It is helpful if all scientists use common procedures as they conducttheir experiments.

A scientific method is a systematic approach used in scientific study,whether it is chemistry, biology, physics, or other sciences. It is an organizedprocess used by scientists to do research, and it provides a method for scien-tists to verify the work of others. An overview of the typical steps of a sci-entific method is shown in Figure 1-9. The steps are not used as a checklistto be done in the same order each time. Therefore, all scientists must describetheir methods when they publish their results. If other scientists cannot con-firm the results after repeating the method, then doubt arises over the valid-ity of the reported results.

Observation You make observations throughout your day in order to makedecisions. Scientific study usually begins with simple observation. An obser-vation is the act of gathering information. Quite often, the types of observa-tions scientists first make are qualitative data—information that describescolor, odor, shape, or some other physical characteristic. In general, anythingthat relates to the five senses is qualitative: how something looks, feels,sounds, tastes, or smells.

Figure 1-8

During your chemistry course,you will have opportunities touse scientific methods to per-form investigations and solveproblems.

10 Chapter 1

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Section Focus Transparency 3What’s killing

the plants?Use with Chapter 1, Section 1.3

What is wrong with this plant?

How could you find out what is harming the plant?1

2

Quick Demo

Logical-MathematicalAsk groups of four

students each to develop a listof the steps they would use tomake a peanut butter and jellysandwich. Then, have eachgroup list their steps on thechalkboard, and have the classcompare lists. Even thougheach group ends up with thesame product, the methodsused may vary. Have studentsrelate this analogy to thedevelopment and use of scientific methods.

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Chemists frequently gather another type of data. For example, they canmeasure temperature, pressure, volume, the quantity of a chemical formed,or how much of a chemical is used up in a reaction. This numerical infor-mation is called quantitative data. It tells you how much, how little, howbig, how tall, or how fast. What kind of qualitative and quantitative data canyou gather from Figure 1-10?

Hypothesis Let’s return to the stories of two chemicals that you read aboutearlier. Even before quantitative data showed that ozone levels were decreas-ing in the stratosphere, scientists observed that CFCs were found there.Chemists Mario Molina and F. Sherwood Rowland were curious about howlong CFCs could exist in the atmosphere.

Molina and Rowland examined the interactions that can occur among var-ious chemicals in the troposphere. They determined that CFCs were stablethere for long periods of time. But they also knew that CFCs drift up into thestratosphere. They formed a hypothesis that CFCs break down in the strato-sphere due to interactions with ultraviolet light from the Sun. In addition, thecalculations they made led them to hypothesize that a chlorine particle pro-duced by this interaction would break down ozone.

A hypothesis is a tentative explanation for what has been observed. Molinaand Rowland’s hypothesis stated what they believed to be happening, eventhough there was no formal evidence at that point to support the statement.

Experiments A hypothesis means nothing unless there are data to support it.Thus, forming a hypothesis helps the scientist focus on the next step in a scien-tific method, the experiment. An experiment is a set of controlled observationsthat test the hypothesis. The scientist must carefully plan and set up one or morelaboratory experiments inorder to change and test onevariable at a time. A variableis a quantity or condition thatcan have more than one value.

Suppose your chemistryteacher asks your class to use the materials shown in Figure 1-11 to design anexperiment in which to testthe hypothesis that table saltdissolves faster in hot waterthan in water at room tem-perature (20°C).

Figure 1-9

The steps in a scientific methodare repeated until a hypothesishas been supported or dis-carded.

EXPE

RIMENTS

REVISED

CONCLU

SIONSHYPOTHESIS

REVISEDTHEORY

TH

EORY

EXPERIMEN

TS

THEORYHypothesissupported by manyexperiments

SCIENTIFICLAW

Summary ofaccepted factsof nature

HYPOTHESISTestable statement orprediction

OBSERVATIONSExisting knowledgeQualitative dataQuantitative data

Figure 1-10

Compare the qualitative andquantitative observations youcan make from this photo withyour classmates. Did you observethe same things?

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Skill Ask students to drawthe steps of a scientific method as aflow chart. Under each heading,have them write a one-sentencedescription of that step.

ExtensionIntrapersonal Using theexample of dissolving salt in

water, ask students to design anexperiment to determine how much salt dissolves at varioustemperatures. Have them identifyconstants, suc ate how they want tovary it. Then have them identify thedependent variable, such as theamount of salt dissolved. If time isavailable, have students performthe experiment and analyze thedata.

In-Text QuestionPage 11 What kind of qualitativeand quantitative data can yougather from Figure 1–10?Qualitative data might includecolors and texture differences.Quantitative data might includerelative masses and lengths.

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ration of solutions. CAUTION: The solu-tions are toxic. Place the NaHSO3 solutionin a beaker labeled 1 and the BaCl2 solutionin a beaker labeled 2. To start the demon-stration, show students the “wine” (KMnO4solution). Pour the “wine” into beaker 1.Pour the “water” that results into beaker 2.

ResultsThe “wine” turns into “water,” and the“water” is then changed into “milk.”

Discussing the chemistry of this demo willbe of little value at this time. Explain thata chemist learns how to change onesubstance into another substance havingdifferent properties.

Analysis1. Were your observations of these

changes qualitative or quantitativedata? Qualitative data; students’sense of sight was used to observecolor changes.

Performance Have studentsmake a poster showing three chemicalsthat they have used in the past week. Usethe Performance Task Assessment List forPoster in PASC, p. 73.

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Because temperature is the variable that you plan to change, it is an independent variable. Your group determines that a given quantity of saltcompletely dissolves within 1 minute at 40°C but that the same quantity ofsalt dissolves only after 3 minutes at 20°C. Thus, temperature affects the rateat which the salt dissolves. This rate is called a dependent variable becauseits value changes in response to a change in the independent variable.Although your group can determine the way the independent variable changes,it has no control over the way the dependent variable changes.

What other factors could you vary in your experiment? Would the amountof salt you try to dissolve make a difference? The amount of water you use?Would stirring the mixture affect your results? The answer can be yes to all ofthese questions. You must plan your experiment so that these variables are the same at each temperature, or you will not be able to tell clearly whatcaused your results. In a well-planned experiment, the independent variableshould be the only condition that affects the experiment’s outcome. A con-stant is a factor that is not allowed to change during the experiment. Theamount of salt, water, and stirring must be constant at each temperature.

In many experiments, it is valuable to have a control, that is, a standardfor comparison. In the above experiment, the room-temperature water is thecontrol. The rate of dissolving at 40°C is compared to the rate at 20°C.Figure 1-12 shows a different type of control. A chemical indicator has beenadded to each of three test tubes. Acid is added to the middle test tube, andthe indicator turns yellow. This test tube can be used as a control. Comparethe other two test tubes with the control. Does either one contain acid?

The interactions described between CFCs and ozone in Molina andRowland’s hypothesis take place high overhead. Many variables are involved.For example, there are different gases present in the stratosphere. Thus, itwould be difficult to determine which gases, or possibly if all gases, aredecreasing ozone levels. Winds, variations in ultraviolet light, and other fac-tors could change the outcome of any experiment on any given day makingcomparisons difficult. Sometimes it is easier to simulate conditions in a lab-oratory where the variables can be more easily controlled.

An experiment may generate a large amount of data. These data must becarefully and systematically analyzed. Because the concept of data analysisis so important, you will learn more about it in the next chapter.

Conclusion Scientists take the data that have been analyzed and apply themto the hypothesis to form a conclusion. A conclusion is a judgment based onthe information obtained. A hypothesis can never be proven. Therefore, to say


Figure 1-11

These materials can be used to determine the effect of temperature on the rate atwhich table salt dissolves.

Figure 1-12

The control test tube in the middle lets you make a visualcomparison.

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Pages 12–133(A), 3(C), 3(E)

IdentifyingMisconceptions

Students often don’t understandwhat a scientific theory is. Manypeople use the term theory toexplain something in the worldaround them or human behavior.What they call a theory might bea hypothesis.Uncover the MisconceptionHave students work in groups todistinguish between a fact and aprediction. Conclusions shouldinclude that a fact has beentested and found to be reliable.A prediction might be based oninformation, but is yet to besupported. Relate these terms to theory and hypothesis.Demonstrate the ConceptWith students, develop an eventschain concept map that showsthe hierarchy of the terms theory,hypothesis, experiments, obser-vations. Concept maps shouldshow that a theory requiresnumerous hypotheses, whichare supported by experimentsthat include observations.Assess New KnowledgeAsk students to describe acommon “theory.” Help themsee that simple statements basedon observations are often reallyhypotheses.

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Gifted Intrapersonal Have gifted studentsfind articles in a recently published

scientific journal on a research topic ofinterest. Have them identify each step ofthe scientific method used in the researchdescribed in the article.

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Qualitative and QuantitativeIntrapersonal Have studentsdescribe themselves using qualitative

and quantitative data. Examples of quali-tative data should use as many senses aspossible: color of hair, tall or short, colorof eyes, etc. Qualitative data may includetheir height or length of hair.

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In-Text QuestionPage 12 Does either one containacid? no

that the data support a hypothesis is to give only a tentative “thumbs up” tothe idea that the hypothesis may be true. If further evidence does not supportit, then the hypothesis must be discarded or modified. The majority ofhypotheses are not supported, but the data may still yield new information.

Molina and Rowland formed a hypothesis about the stability of CFCs inthe stratosphere. They gathered data that supported their hypothesis and devel-oped a model in which the chlorine formed by the breakdown of CFCs wouldreact over and over again with ozone. You must realize by now a model is avisual, verbal, and/or mathematical explanation of experimental data.

A model can be tested and used to make predictions. Molina and Rowland’smodel predicted the formation of chlorine and the depletion of ozone, asshown in Figure 1-13. Another research group found evidence of interactionsbetween ozone and chlorine when taking measurements in the stratosphere,but they did not know the source of the chlorine. Molina and Rowland’s modelpredicted a source of the chlorine. They came to the conclusion that ozone inthe stratosphere could be destroyed by CFCs and that they had enough sup-port for their hypothesis to publish their discovery.

Theory A theory is an explanation that has been supported by many, manyexperiments. You may have heard of Einstein’s theory of relativity or theatomic theory. A theory states a broad principle of nature that has been sup-ported over time. All theories are still subject to new experimental data andcan be modified. Also, theories often lead to new conclusions.

A theory is considered successful if it can be used to make predictions thatare true. In 1985, the announcement by the British Antarctic Survey that theamount of ozone in the stratosphere was decreasing lent Molina and Rowland’shypothesis—that chlorine from CFCs could destroy ozone—further support.

Scientific law Sometimes, many scientists come over and over again to thesame conclusion about certain relationships in nature. They find no excep-tions. For example, you know that no matter how many times skydivers leapfrom a plane, they always wind up back on Earth’s surface. Sir Isaac Newtonwas so certain that an attractive force exists between all objects that he pro-posed his law of universal gravitation.

Newton’s law is a scientific law and, as such, a relationship in nature thatis supported by many experiments. It is up to scientists to develop furtherhypotheses and experimentation to explain why these relationships exist.

1.3 Scientific Methods 13


11. What is a scientific method? What are its steps?

12. You are asked to study the effect of temperatureon the volume of a balloon. The balloon’s sizeincreases as it is warmed. What is the independentvariable? Dependent variable? What factor is heldconstant? How would you construct a control?

13. Critique Molina and Rowland’s hypothesis ofozone depletion as to its strengths and weaknesses.

14. Jacques Charles described the direct relationshipbetween temperature and volume of all gases at

constant pressure. Should this be called Charles’slaw or Charles’s theory? Explain.

15. Thinking Critically Why must Molina andRowland’s data in the laboratory be supported bymeasurements taken in the stratosphere?

16. Interpreting Data A report in the media statesthat a specific diet will protect individuals fromcancer. However, no data are reported to supportthis statement. Is this statement a hypothesis or aconclusion?

Figure 1-13

Molina and Rowland’s modelpredicted that ultraviolet radia-tion causes a chlorine particle tosplit off from a CFC.

The chlorine particle thendestroys the ozone by combin-ing with it to form oxygen gasand chlorine monoxide.

b

a

Ultravioletradiation

OzoneChlorine

Chlorinemonoxide

Oxygen gas

Chlorine

CFC

�

�

b

a a

b

3 AssessCheck for UnderstandingAsk students to explain the differ-ence between a hypothesis and atheory. A hypothesis is a state-ment about what is believed tobe happening, without evidence.A theory is formed over time andis confirmed by verification ofmany hypotheses by experiments.

ReteachHave students clarify the differencebetween a theory and a scientificlaw. A theory is a statement thatprovides an explanation basedon supported hypotheses. Ascientific law describes somethingknown to happen without error,such as gravity, but doesn’texplain how it happens.

ExtensionBring in a newspaper or journalarticle about a development inenvironmental chemistry. Havestudents identify the steps of ascientific method used as well as any controls and variables used.

Performance Cut outlarge pieces of paper and write avocabulary word from this sectionon each. Have students place thesepapers in the order they are used ina scientific method. Some wordsmay be subsets of specific steps.Accept any order that students canjustify. Use the Performance TaskAssessment List for Events Chainin PASC, p. 91. L2

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11. a systematic approach used inscientific study; observation,hypothesis, experiment, dataanalysis, conclusion

12. the temperature; the size of theballoon; the amount of air in theballoon; an identical ballon kept atroom temperature

13. Answers might include that scien-tific evidence supports the hypoth-esis, but the hypothesis must betested using models instead ofactually observing the reaction.

14. It is called Charles’s law because itdescribes a phenomenon thatconsistently takes place.

15. In the lab, conditions are carefullycontrolled. In the stratosphere,conditions vary widely. Data must show that the samephenomena occur in an unstruc-tured environment.

16. It is only a hypothesis unless datasupports it.

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Focus Transparency


Section 1.4 Scientific Research

Objectives• Compare and contrast pure

research, applied research,and technology.

• Apply knowledge of labora-tory safety.

Vocabularypure researchapplied researchtechnology

Every day in the media, whether it’s TV, newspapers, magazines, or theInternet, you are bombarded with the results of scientific investigations. Manydeal with the environment, medicine, or health. As a consumer, you are askedto evaluate the results of scientific research and development. How do scien-tists use qualitative and quantitative data to solve different types of scientificproblems?

Types of Scientific InvestigationsPure research seeks to gain knowledge for the sake of knowledge itself.Molina and Rowland conducted research on CFCs and their interactions withozone as pure research, motivated by curiosity. No environmental evidenceat the time indicated that there was a correlation to their model in the strato-sphere. Their research only showed that CFCs could speed the breakdown ofozone in a laboratory setting.

When the ozone hole was reported in 1985, scientists had made measure-ments of CFC levels in the stratosphere that supported the hypothesis thatCFCs could be responsible for the depletion of ozone. The pure research doneonly for the sake of knowledge became applied research. Applied researchis research undertaken to solve a specific problem. Scientists continue tomonitor the amount of CFCs in the atmosphere and the annual changes in theamount of ozone in the stratosphere. Applied research also is being done tofind replacement chemicals for the CFCs that are now banned. Read theChemistry and Society feature at the end of this chapter to learn aboutresearch into the human genome. What type of research does it describe?

Chance discoveries Sometimes, when a scientist plans research with aspecific goal in mind, he or she will conduct experiments and reach a con-clusion that is expected. Sometimes, however, the conclusion reached is fardifferent from what was expected. Some truly wonderful discoveries in sci-ence have been made unexpectedly.

The discovery of nylon is one example. In 1928, E.I. DuPont de Nemoursand Company appointed a young, 32-year-old chemist from Harvard,Wallace Carothers, as the director of its new research center. The goal wasto create artificial fibers similar to cellulose and silk. In 1930, Julian Hill,a member of Carothers’ team, dipped a hot glass rod in a mixture of solu-tions and unexpectedly pulled out long fibers such as the one shown inFigure 1-14. Carothers pursued the development of these fibers as a syn-thetic silk that could withstand high temperatures and eventually developednylon in 1934. Nylon’s first use was in a toothbrush with nylon bristles.During World War II, nylon was used as a replacement for silk in parachutes.Nylon is used extensively today in textiles and some kinds of plastics.

Students in the LaboratoryIn your study of chemistry, you will learn many facts about matter. You also willdo experiments in which you will be able to form and test hypotheses, gatherand analyze data, and draw conclusions.

When you work in the chemistry laboratory, you are responsible for yoursafety and the safety of the people working nearby. Table 1-2 on page 16 listssome safety rules that you must use as a guide each time you enter the lab.

BiologyCONNECTION

Many discoveries in science aremade quite unexpectedly.

Alexander Fleming is famous formaking two such discoveries. Thefirst occurred in 1922, when nasalmucus accidentally dripped ontobacteria that he had been grow-ing for research. Rather thanthrowing the culture plate away,he decided to observe it over thenext several days. He found thatthe bacteria died. As a result, hediscovered that lysozyme, a chem-ical in mucus and tears, helps pro-tect the body from bacteria.

Six years later, in 1928, Flemingfound that one of his plates ofStaphylococcus bacteria had beencontaminated by a greenish mold,later identified as Penicillium. Heobserved it carefully and saw aclear area around the mold wherethe bacteria had died. In this case,a chemical in the mold—peni-cillin—was responsible for killingthe bacteria.

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Section Focus Transparency 4 Scientific Research

Use with Chapter 1, Section 1.4



What research might this scientist be doing?

What practical application might there be to this

research?

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Bring in samples of nylon clothand nylon cord. Nylon is agood example of a syntheticcompound that has many uses.Explain that many such appli-cations are chance discoveriesthat are byproducts of purescience.

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Research or DiscoveryIntrapersonal Have students clip anewspaper article describing a scien-

tific study. Ask them to discuss whetherthis example is pure research, appliedresearch, or a chance discovery.

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In-Text QuestionsPage 14 What type of researchdoes it describe? both pure andappliedPage 15 Which safety rules inTable 1-2 apply to the ChemLaband MiniLab? MiniLab: 1 through9, 21, 24; ChemLab: 1 through 9,24; student answers might varyslightly.

15

Chemists and all other scientists use these safety rules. Before you do theminiLAB at the bottom of this page or the CHEMLAB at the end of thischapter, read the procedures carefully. Which safety rules in Table 1-2apply?

1.4 Scientific Research 15

Figure 1-14

Strands of nylon can be pulledfrom the top layer of solutions.After its discovery, nylon wasused mainly for war materialsand was unavailable for homeuse until after World War II.

Developing Observation SkillsObserving and Inferring A chemist’s ability tomake careful and accurate observations is devel-oped early. The observations often are used tomake inferences. An inference is an explanationor interpretation of observations.

Materials petri dish (2), graduated cylinder,whole milk, water, vegetable oil, four differentfood colorings, toothpick (2), dishwashing detergent

Procedure 1. Add water to a petri dish to a height of

0.5 cm. Add 1 mL of vegetable oil.

2. Dip the end of a toothpick in liquid dishwash-ing detergent.

3. Touch the tip of the toothpick to the water atthe center of the petri dish. Record yourdetailed observations.

4. Add whole milk to a second petri dish to aheight of 0.5 cm.

5. Place one drop each of four different food col-orings in four different locations on the sur-face of the milk, as shown in the photo. Donot put a drop of food coloring in the center.

6. Repeat steps 2 and 3.

Analysis 1. What did you observe in step 3?

2. What did you observe in step 6?

3. Oil, the fat in milk, and grease belong to aclass of chemicals called lipids. What can youinfer about the addition of detergent to dish-water?

miniLAB

Purpose Students will develop a hypothesisbased on careful observations.

Process SkillsObserving and inferring, drawing aconclusion, hypothesizing,designing an experiment

DisposalFlush the contents of the dish downthe sink drain with plenty of water.

Teaching Strategies• As a pre-lab activity, have

students do Internet or libraryresearch on the composition ofmilk. Visit science.glencoe.com.

• Students can float pepper on themilk to trace movement if foodcoloring isn’t available.

Expected ResultsWhen the toothpick touches themilk, the detergent temporarilydestroys the surface tension. Thecolors move to the outside of thedish. The detergent emulsifies anyfat in the milk. Convectionlikecurrents are established, causingthe colors to move from the outsidetoward the center.

Analysis1. The oil moved away from the

detergent.2. The colors moved to the

outside of the dish.3. It helps remove grease and oil

from items being washed.

Performance Havedifferent lab groups test milksamples that have different fatcontent and then compare theirobservations. Use the PerformanceTask Assessment List for CarryingOut a Strategy and Collecting Data in PASC, p. 25.

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English Language LearnersInterpersonal Have a student explainthe difference between pure and

applied research and chance discovery toan English-language-learning student. Thestudent can use figures in the textbook tohelp him or her explain.

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VIDEODISCCosmic ChemistryDisc 3, Side 6Movie: Nylon 1:11 min

Development of the copolymer nylon

{cÿπÅŸ°◊}

CHEMLABChemLab 1, located at the end ofthe chapter, can be used at thispoint in the lesson.



Safety in the Laboratory

1. Study your lab assignment before you come to thelab. If you have any questions, be sure to ask yourteacher for help.

2. Do not perform experiments without your teacher’spermission. Never work alone in the laboratory.

3. Use the table on the inside front cover of this text-book to understand the safety symbols. Read allCAUTION statements.

4. Safety goggles and a laboratory apron must be wornwhenever you are in the lab. Gloves should be wornwhenever you use chemicals that cause irritations orcan be absorbed through the skin. Long hair must betied back. See the photo below.

5. Do not wear contact lenses in the lab, even undergoggles. Lenses can absorb vapors and are difficult toremove in case of an emergency.

6. Avoid wearing loose, draping clothing and danglingjewelry. Bare feet and sandals are not permitted inthe lab.

7. Eating, drinking, and chewing gum are not allowedin the lab.

8. Know where to find and how to use the fire extin-guisher, safety shower, fire blanket, and first-aid kit.

9. Report any accident, injury, incorrect procedure, ordamaged equipment to your teacher.

10. If chemicals come in contact with your eyes or skin,flush the area immediately with large quantities ofwater. Immediately inform your teacher of the nature of the spill.

11. Handle all chemicals carefully. Check the labels of allbottles before removing the contents. Read the labelthree times:

• Before you pick up the container.• When the container is in your hand.• When you put the bottle back.

12. Do not take reagent bottles to your work area unlessinstructed to do so. Use test tubes, paper, or beakersto obtain your chemicals. Take only small amounts. Itis easier to get more than to dispose of excess.

13. Do not return unused chemicals to the stock bottle.

14. Do not insert droppers into reagent bottles. Pour asmall amount of the chemical into a beaker.

15. Never taste any chemicals. Never draw any chemicalsinto a pipette with your mouth.

16. Keep combustible materials away from open flames.

17. Handle toxic and combustible gases only under thedirection of your teacher. Use the fume hood whensuch materials are present.

18. When heating a substance in a test tube, be carefulnot to point the mouth of the test tube at anotherperson or yourself. Never look down the mouth of atest tube.

19. Do not heat graduated cylinders, burettes, orpipettes with a laboratory burner.

20. Use caution and proper equipment when handlinghot apparatus or glassware. Hot glass looks the sameas cool glass.

21. Dispose of broken glass, unused chemicals, and prod-ucts of reactions only as directed by your teacher.

22. Know the correct procedure for preparing acid solu-tions. Always add the acid slowly to the water.

23. Keep the balance area clean. Never place chemicalsdirectly on the pan of a balance.

24. After completing an experiment, clean and put awayyour equipment. Clean your work area. Make surethe gas and water are turned off. Wash your handswith soap and water before you leave the lab.

Table 1-2

16

Applying ChemistryAsk students if thediscovery of CFCs waspure research, appliedresearch, or chancediscovery. It was applied

research to find another sourceof refrigerants.

ReinforcementInterpersonal Dividestudents into groups of four.

Give each group several safety tipsfrom Table 1-2. Have them create aquick skit to demonstrate potentialdangers and lab safety.

Concept DevelopmentAs the instructor, walk into the labdemonstrating poor lab safety, suchas wearing loose clothing andchewing gum. Have students iden-tify as many rules you are breakingas they can. Have a prize, such as aspecial pair of lab goggles, for thestudent or group who identifies thegreatest number of broken rules.Emphasize that although thisexample can be humorous, labsafety is a serious issue.

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VIDEODISCCosmic ChemistryDisc 1, Side 1Movie: Dr. Jekyll andMr. Hyde 1:16 min

John Barrymore makes thepoint for laboratory safety

{`C§B£aÿ}Movie: Lab Safety 3:21 minGeneral safety tips for laboratory work

{`ftH£°–} PortfolioPortfolio

Visual-Spatial Have student groupscreate posters or a bulletin board

that emphasizes safe lab procedures. Besure the products reflect what the safebehavior is and why it should be used.

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Lab SafetyResource ManagerResource Manager

Teaching Transparency 3 and Master

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Benefits of ChemistryIt is easy to understand the purpose of applied research because it addressesa specific problem. It also is easier to see its immediate benefit. Yet, when asudden, unexpected event occurs in the world, whether it’s the ozone hole orthe AIDS epidemic, the first line of defense is to look at the pure researchthat has already been conducted.

The products that we use to make our lives easier and more comfortableare the result of technological applications of pure and applied research.Technology is the practical use of scientific information. It is concerned withmaking improvements in human life and the world around us. As Figure 1-15shows, advances in technology can benefit us in many ways.

1.4 Scientific Research 17

Figure 1-15

Nuclear power and artificiallimbs and joints are just a few ofthe technological advances thathave improved human life.


17. Compare and contrast pure research and appliedresearch.

18. What is technology? Is technology a product ofpure research or applied research? Explain.

19. Explain why it is important to read each CHEM-LAB and miniLAB before you come to class.

20. Thinking Critically Explain the reason behindeach of the following.

a. Wear goggles and an apron in the lab even ifyou are only an observer.

b. Report all accidents to your teacher.c. Do not return unused chemicals to the stock

bottle.21. Interpreting Scientific Diagrams What safety

precautions should you take when you see the fol-lowing safety symbols?

3 AssessCheck for UnderstandingAsk students whether they thinkresearch on the Human GenomeProject is pure or applied. Ifstudents are unfamiliar with theproject, have them read theChemistry and Society on page 20of this text. Answers will vary butmight include that it is pureresearch for knowledge of what’sin the genome. Some studentsmight say it is applied because ofits use in gene therapy and curesfor genetic diseases.

ReteachEmphasize that pure research isoften a foundation for appliedresearch. Pure research can createcompounds or increase knowledgethat scientists may not know howto use for years. However, whenthat knowledge or material isneeded, it is readily available.

ExtensionAsk students to bring in newspaperor magazine articles about scien-tific research and explain to theclass how that research applies totheir lives. Examples may include anew drug or treatment for a diseasethat affects someone they know ornew technology that affects theenvironment.

Portfolio Have studentssummarize articles brought in bysome of the other students for theExtension above. Have studentsplace the summaries into theirportfolios. PP

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17. Pure research is done for the sakeof knowledge. Applied research isdone to solve a specific problem.

18. Technology is the practical use ofscientific information and is theresult of both pure and appliedresearch.

19. You need to know what the objec-tives are, safety precautions, mate-rials needed, and how to managetime.

20. a. Materials can spatter or spill.b. Specific means of disposal or

cleanup might be needed.c. They might be contaminated.

21. Use proper protection whenhandling materials that are cold orhot. Make sure the area is wellventilated; never smell fumesdirectly; wear a mask. Wear dustmask and gloves; practice extracare when handling materials.Avoid open flames.

17

Pre-Lab

Pre-Lab

1. Heat is the transfer of energy from a warmer objectto a cooler object. If an object feels warm to yourfinger, your finger is cooler than the object andenergy is being transferred from the object to yourfinger. In what direction does the energy flow if anobject feels cooler to you?

2. Your forehead is very sensitive to hot and cold.How can you use this fact to detect whether anobject is giving off or absorbing heat?

3. Read the entire CHEMLAB. It is important toknow exactly what you are going to do during allchemistry experiments so you can use your labora-tory time efficiently and safely. What is the prob-lem that this experiment is going to explore?

4. What typical steps in a scientific method will youuse to explore the problem? Write down the proce-dure that you will use in each experiment that youdesign. Be sure to include all safety precautions.

5. You will need to record the data that you collectduring each experiment. Prepare data tables thatare similar to the one below.

Rubber Band Data

Experiment # Observations

Trial 1

Trial 2

Trial 3

Trial 4


Safety Precautions

• Frequently observe the rubber band for any splits. Discard if rubber band isdefective.

• The hair dryer can become hot, so handle it with care.

ProblemWhat happens when youheat a stretched rubberband?

Objectives• Observe the properties of a

stretched and a relaxed rubber band.

• Form a hypothesis aboutthe effect of heat on astretched rubber band.

• Design an experiment totest your hypothesis.

• Collect and analyze data.• Draw conclusions based on

your analysis.

Materialslarge rubber band500-g massring standclamphair dryermeter stick or ruler

The Rubber Band StretchGalileo Galilei (1564–1642) was an Italian philosopher, astronomer,

and mathematician. Galileo pioneered the use of a systematicmethod of observation, experimentation, and analysis as a way todiscover facts about nature. Modern science has its roots in Galileo’s17th-century work on the art of experimentation. This chapter intro-duced you to how scientists approach their work. In this CHEMLAB,you will have a chance to design a scientific method to study some-thing you have observed many times before—the stretching of a rub-ber band.

CHEMLAB 1

18

Expected ResultsObservations should reflect that a rubber bandgives off heat when it stretches, absorbs heatwhen it contracts, and contracts when heated.

Analyze and Conclude1. The rubber band feels warm. Energy was

lost by the rubber band and gained bythe forehead.

2. The rubber band feels cooler. Heat isgained by the rubber band and lost bythe forehead.

3. When heated, a stretched rubber band contracts.

4. Most students would hypothesize thatthe rubber band would stretch whenheated. The actual result refuted thehypothesis. The rubber band becameshorter.

1CHEMLAB

Preparation Time AllotmentOne laboratory period

Process SkillsAnalyzing and concluding,collecting and interpreting data,comparing and contrasting,designing an experiment, hypothe-sizing, measuring, observing andinferring, thinking critically

Safety PrecautionsRemind students to use the rubberbands properly and responsibly.Ensure that students wear gogglesthroughout the activity. Rubberbands can accidentally injure eyes.Caution students that hair dryersbecome hot.

Disposal Keep the rubber bands for reuse.

Preparation• Give students some time before

the lab period to plan how theywill design their experiments.

• Ask students to bring in hairdryers from home.

1. from the warmer object (yourfinger) to the cooler one (theobject)

2. The sensitive skin on the fore-head tells that an object isgiving off heat if it feels warmon your forehead andabsorbing heat if it feels cool.

3. What happens when you heata stretched rubber band?

4. Check student procedures toassure they follow a correctscientific method.

5. See Expected Results.

Procedure• Check the students’ experimental

designs before they do the experi-ments.

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19

CHEMLAB 19

Procedure

1. Obtain one large rubber band. Examine the rubberband for any splits or cracks. If you find anydefects, discard it and obtain a new one.

2. Record detailed observations of the unstretchedrubber band.

3. Design your first experiment to observe whetherheat is given off or absorbed by a rubber band as itis stretched. Have your instructor approve yourplan.

4. Do repeated trials of your experiment until you aresure of the results. CAUTION: Do not bring therubber band near your face unless you are wearinggoggles.

5. Design a second experiment to observe whetherheat is given off or absorbed by a rubber band as itcontracts after being stretched. Have your instruc-tor approve your plan.

6. Do repeated trials of your experiment until you aresure of the results.

7. Use your observations in steps 2, 4, and 6 to forma hypothesis and make a prediction about what willhappen to a stretched rubber band when it isheated.

8. Use the remaining items in the list of materials todesign a third experiment to test what happens to astretched rubber band as it is heated. Have your

instructor approve your plan. Be sure to record allobservations before, during, and after heating.

Cleanup and Disposal

1. Return the rubber band to your instructor to bereused by other classes.

2. Allow the hair dryer to cool before putting it away.

Analyze and Conclude

1. Observing and Inferring What results did youobserve in step 4 of the procedure? Was energygained or lost by the rubber band? By your fore-head? Explain.

2. Observing and Inferring What results did youobserve in step 6 of the procedure? Was energygained or lost by the rubber band? By your fore-head? Explain.

3. Applying Many substances expand when they areheated. Did the rubber band behave in the sameway? How do you know?

4. Drawing a Conclusion Did the result of heatingthe stretched rubber band in step 8 confirm orrefute your hypothesis? Explain.

5. Making Predictions What would happen if youapplied ice to the stretched rubber band?

6. Compare your results and con-clusion with those of your classmates. What wereyour independent and dependent variables? Didyou use a control? Did all of the lab teams measurethe same variables? Were the data that you col-lected qualitative or quantitative? Does this make adifference when reporting your data to others? Doyour results agree? Why or why not?

Real-World Chemistry

1. When you put ice in a glass so that the ice riseshigher than the rim, water does not overflow theglass when the ice melts. Explain.

2. Why do you think temperature extremes must betaken into account when bridges and highways aredesigned?

Error Analysis

CHAPTER 1 CHEMLAB

5. Predictions should include thatit would stretch.

6. Student controls and variableswill vary by student and byexperiment. Sample answersmight be: independentvariable—degree ofstretching; dependentvariable—temperature;control—temperature of anunstretched rubber band. Thedata is qualitative because noactual measurements weremade. A source of error mightbe time lags after stretchingthe rubber bands that allowtemperature to change.

Real-World Chemistry1. Water expands when frozen.

When ice melts, the watertakes up less volume.

2. The materials that make upthe bridge expand in warmweather and contract in coldweather. Bridge materials willcrack if nothing is done toallow the bridge to expandand contract.

Performance Design anexperiment like the one done inProcedure step 8, but cool therubber band instead of heating it.Use the Performance TaskAssessment List for Designing anExperiment in PASC, p. 23.



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Note Internet addresses that you find useful in thespace below for quick reference.

20

Purpose Students will learn about theHuman Genome Project, includinghow scientific methods are used tofurther project goals and societalissues raised by the research.

BackgroundThe goals of the Human GenomeProject (HGP) include identifyingall of the tens of thousands ofgenes in human DNA, determiningthe sequences of the 3 billionchemical bases that make up DNA,and storing this information inpublicly accessible databases. Itwill attempt to make its findingsavailable at no cost to otherresearchers around the world. Thesequences identified by privatecompanies will not be availablepublicly. It is the first scientificeffort of its size to address relatedlegal, social, and ethical issues.HGP scientists are also decodingthe genomes of the fruit fly, labmouse, and E. coli bacterium.Studying nonhuman DNA mayhelp researchers to address issuesrelated to agriculture, energy, andenvironmental cleanup.

Teaching Strategies• Provide students with examples

of genetic diversity in humans.Create a class list that showssome of the variety in traitsexpressed by human DNA.

• Have students research termi-nology associated with geneticresearch, including genome, gene,chromosome, and protein.

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CHEMISTRY and

Society

From eye and skin color to the potential for devel-oping disease, humans display remarkable and end-less variety. Much of this variety is controlled bythe human genome: the complete “instruction man-ual” found in the nucleus of all cells that is used todefine a specific organism. Decoding and under-standing these instructions is the goal of the HumanGenome Project (HGP). The United StatesDepartment of Energy and the National Institutesof Health coordinated the project that began in1990. Private industry also is involved. The HGPfosters cooperation as well as competition amongresearchers in a project that could hasten advancesin treatment of human genetic conditions such ascancer and heart disease.

A common goal, a commonapproach The year 2003 marks the fiftieth anniversary ofWatson and Crick’s discovery of the structure ofDNA. Chemicals called nitrogen bases connect thetwisted strands that make up DNA. There areroughly three billion pairs of these bases in thehuman genome. Determining the sequence, ororder, in which these base pairs occur was one com-mon goal of researchers working on the HGP.Biologists, chemists, physicists, computer special-ists, and engineers across the country approach thetask from different angles. Use of scientific meth-ods was the unifying theme in all of this work.

Prior to the HGP, researchers around the worldused scientific methods to work independently onthe mammoth task of decoding the human genome.Without coordination, however, the data they col-lected were analyzed and stored using differentdatabases and were shared only through scientificjournals and conferences. Those working on theHGP used common methods for gathering and ana-lyzing data. Results were shared through databasesthat are rapidly available through the World WideWeb, enhancing communication, cooperation, andthe flow of information. Because of this coopera-tion, a rough map of the human genome was com-pleted several years ahead of schedule. Much workstill remains to be done, however, and results will

have to be shared by researchers working on theproject.

Looking toward the futureThe Human Genome Project is spurring medicaladvances. But this powerful knowledge also raisesimportant issues. For example, if a person’s genomemap shows a predisposition for a certain illness,should an employer or insurance company beinformed? While the HGP is opening excitingdoors, the associated ethical, legal, and societalissues must be acknowledged and addressed.

1. Communicating Ideas Research some ofthe ethical, legal, and societal issues beingraised by genome research. Write a brief essaygiving your opinion about how one or more ofthese issues could be addressed.

2. Debating the Issue The race to sequence thehuman genome took place in both the publicand private sectors. Find information about sev-eral companies that worked independently ongenome research. Is it ethical for them to sellthis information, or should it be freely sharedwith others?

Investigating the Issue

The Human Genome Project

CHEMISTRY and

Society

Visit the Chemistry Web site at science.glencoe.com to find links to more infor-mation about the Human Genome Project.


Investigating the Issue1. Students will have varying opinions on

issues such as whether testing for geneticcompatibility should be required prior tomarriage; who should receive informa-tion about the results of genetic tests,including employers and insurance

companies; and what is done if genetictesting shows a predisposition for devel-oping certain illnesses.

2. Students will have a variety of reactionsto a company’s right to research, orga-nize, and sell information it acquiresusing its own funds.


Pages 20–213(A)

Study Guide 21

CHAPTER STUDY GUIDE1

Vocabulary

Summary1.1 The Stories of Two Chemicals• The building blocks of the matter in the universe

formed in the stars.

• A chemical is any substance that has a definite composition.

• Ozone is a chemical that forms a protective layer inEarth’s atmosphere.

• Ozone is formed in the stratosphere when ultravioletradiation from the Sun strikes oxygen gas.

• Thinning of the ozone layer over Antarctica is calledthe ozone hole.

• CFCs are synthetic chemicals made of chlorine, flu-orine, and carbon.

• CFCs were used as refrigerants and as propellants inaerosol cans.

• CFCs can drift into the stratosphere.

1.2 Chemistry and Matter• Chemistry is the study of matter and the changes

that it undergoes.

• Matter is anything that has mass and takes up space.

• Mass is a measure of the amount of matter.

• Weight is a measure not only of an amount of matterbut also the effect of Earth’s gravitational pull onthat matter.

• There are five traditional branches of chemistry:organic chemistry, inorganic chemistry, physicalchemistry, analytical chemistry, and biochemistry.

• Macroscopic observations of matter reflect theactions of atoms on a submicroscopic scale.

1.3 Scientific Methods• Typical steps of a scientific method include observa-

tion, hypothesis, experiments, data analysis, andconclusion.

• Qualitative data describe an observation; quantita-tive data use numbers.

• An independent variable is a variable that youchange in an experiment.

• A dependant variable changes in response to achange in the independent variable.

• A theory is a hypothesis that has been supported bymany experiments.

• A scientific law describes relationships in nature.

1.4 Scientific Research• Scientific methods can be used in pure research for

the sake of knowledge, or in applied research tosolve a specific problem.

• Laboratory safety is the responsibility of anyonewho conducts an experiment.

• Many of the conveniences we enjoy today are tech-nological applications of chemistry.

• applied research (p. 14)• chemistry (p. 7)• conclusion (p. 12)• control (p. 12)• dependent variable (p. 12)• experiment (p. 11)• hypothesis (p. 11)

• independent variable (p. 12)• mass (p. 8)• matter (p. 8)• model (p. 13)• pure research (p. 14)• qualitative data (p. 10)• quantitative data (p. 11)

• scientific law (p. 13)• scientific method (p. 10)• technology (p. 17)• theory (p. 13)• weight (p. 8)

Using the VocabularyTo reinforce chapter vocabulary,have students write a sentenceusing each term.

Review Strategies • Have students define chemistry,

chemical, matter, mass, andweight.

• Have students summarize thesteps of a scientific method,giving examples of each step.

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CHAPTERSTUDY GUIDE 1

Reviewing Chemistry is a compo-nent of the Teacher ClassroomResources package that wasprepared by The PrincetonReview. Use the Chapter 1review materials in this book to review the chapter with yourstudents.

VIDEOTAPE/DVDMindJoggerVideoquizzesChapter 1: Introduction toChemistry

Have students work in groups as they play the videoquiz gameto review key chapter concepts.

PortfolioPortfolio

Review the portfolio options that are pro-vided throughout the chapter. Encouragestudents to select one product that demon-strates their best work for the chapter. Havestudents explain what they have learned

and why they chose this example for place-ment into their portfolios. Additional port-folio options may be found in the ChallengeProblems booklet of the Teacher ClassroomResources. PP

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Go to the Chemistry Web site at science.glencoe.com or use the Chemistry CD-ROM for additional Chapter 1 Assessment.

Concept Mapping22. Complete the concept map using the following terms:

stratosphere, oxygen gas, CFCs, ozone, ultravioletradiation.

Mastering Concepts23. What is a chemical? (1.1)

24. Where is ozone located in Earth’s atmosphere? (1.1)

25. Explain the balance between oxygen and ozone in thestratosphere. Why is it important? (1.1)

26. What were common uses of CFCs? (1.1)

27. What is chemistry? (1.2)

28. Why is chemistry called the central science? (1.2)

29. Which measurement depends on gravitational force—mass or weight? Explain. (1.2)

30. Which branch of chemistry studies the composition ofsubstances? Environmental impact of chemicals? (1.2)

31. How does qualitative data differ from quantitativedata? Give examples of each. (1.3)

32. What is the function of a control in an experiment? (1.3)

33. What is the difference between a hypothesis, a theory,and a law? (1.3)

34. In the study of water, what questions might be askedin pure research? Applied research? Technology? (1.4)

Thinking Critically35. Compare and Contrast Why is CFC depletion of

the ozone layer a theory and not a scientific law?

36. Classifying CFCs break down to form chemicals thatreact with ozone. Is this a macroscopic or a micro-scopic observation?

37. Communicating Ideas Scientists often learn asmuch from an incorrect hypothesis as they do fromone that is correct. Explain.

38. Designing an Experiment How would you designan experiment to evaluate the effectiveness of a “newand improved” chemical fertilizer on bean plants? Besure to describe your hypothesis, procedure, variables,and control.

39. Inferring A newscaster reports, “The air qualitytoday is poor. Visibility is only a quarter mile.Pollutants in the air are expected to rise above 0.085parts per million (ppm) in the next eight hour average.Spend as little time outside today as possible if yousuffer from asthma or other breathing problems.”Which of these statements are qualitative and whichare quantitative?

40. Comparing and Contrasting Match each of thefollowing research topics with the branch of chemistrythat would study it: water pollution, the digestion offood in the human body, the composition of a new tex-tile fiber, metals to make new coins, a treatment forAIDS.

Writing in Chemistry41. Based on your beginning knowledge of chemistry,

describe the research into depletion of the ozone layerby CFCs in a timeline.

42. Learn about the most recent measures taken by coun-tries around the world to reduce CFCs in the atmos-phere since the Montreal Protocol. Write a short reportdescribing the Montreal Protocol and more recentenvironmental measures to reduce CFCs.

43. Name a technological application of chemistry thatyou use everyday. Prepare a booklet about its discov-ery and development.

Cumulative ReviewIn chapters 2 through 26, this heading will be followed by questions that review your understanding of previouschapters.

CHAPTER ASSESSMENT1

is formedin the

when

breaks up

is destroyedby

1.

2. 5.

3.

4.

22

Concept Mapping22. 1. ozone; 2. stratosphere;

3. ultraviolet radiation; 4. oxygen gas; 5. CFCs

Mastering Concepts23. any substance with a

definite composition24. 90% in the stratosphere25. Chemical reactions in the

atmosphere form ozonefrom oxygen and oxygenfrom ozone. Ozone protectsEarth from UV rays.

26. refrigerants, foams, propel-lants for spray products

27. the study of matter andthe changes it undergoes

28. An understanding of chem-istry is central to all sciencesand to our everyday lives.

29. Weight depends on gravi-tational force and changesas the gravitational forcechanges. Mass remains thesame.

30. Analytical chemistry studiesthe composition of sub-stances; environmentalchemistry studies the environmental impact ofchemicals.

31. Qualitative data, such ascolor or shape, areobserved with the fivesenses. Quantitative data,such as mass or length, aremeasurements.

32. A control is a standardused for comparison.

33. A hypothesis is a tentativeexplanation about whathas been observed. Atheory is an explanationthat has been supported bymany experiments. A scien-tific law describes a rela-tionship in nature.

34. Pure research might examine theproperties of water. Applied researchmight ask what chemicals should beadded to drinking water to promotehealth, such as fluoride to promotehealthy tooth formation. Technologymight include creating filters to filterharmful contaminants out of water or machines to purify it.

CHAPTERASSESSMENT 1

All Chapter Assessment questionsand answers have been validatedfor accuracy and suitability byThe Princeton Review.


Chapter Assessment, pp. 1–6 Supplemental Problems, Ch. 1TestCheck SoftwareMindJogger VideoquizzesSolutions Manual, Ch. 1Chemistry Interactive CD-ROM, Ch. 1 quiz

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Standardized Test Practice 23

Use these questions and the test-taking tip to preparefor your standardized test.

1. Matter is defined as anything that _____.

a. exists in natureb. is solid to the touchc. is found in the universed. has mass and takes up space

2. Mass is preferred as a measurement over weight for allof the following reasons EXCEPT _____.a. it has the same value everywhere on Earthb. it is independent of gravitational forcesc. it becomes less in outer space, farther from Earthd. it is a constant measure of the amount of matter

3. Which of the following is an example of pureresearch?

a. creating synthetic elements to study their propertiesb. producing heat-resistant plastics for use in house-

hold ovensc. finding ways to slow down the rusting of iron shipsd. searching for fuels other than gasoline to power

cars

4. When working with chemicals in the laboratory, whichof the following is something you should NOT do?

a. Read the label of chemical bottles before usingtheir contents.

b. Pour any unused chemicals back into their originalbottles.

c. Use lots of water to wash skin that has beensplashed with chemicals.

d. Take only as much as you need of shared chemicals.

Interpreting Tables and Graphs Use the table andgraph to answer questions 5–7.

5. What must be a constant during the experiment?

a. temperatureb. mass of CO2 dissolved in each samplec. amount of beverage in each sampled. independent variable

6. Assuming that all of the experimental data are correct,what is a reasonable conclusion for this experiment?

a. Greater amounts of CO2 dissolve in a liquid atlower temperatures.

b. The different samples of beverage contained thesame amount of CO2 at each temperature.

c. The relationship between temperature and solubil-ity seen with solids is the same as the one seenwith CO2.

d. CO2 dissolves better in a liquid at higher tempera-tures.

7. The scientific method used by this student showed that_____.

a. the hypothesis is supported by the experimentaldata

b. the observation accurately describes what occurs innature

c. the experiment is poorly plannedd. the hypothesis should be thrown out

STANDARDIZED TEST PRACTICECHAPTER 1

More Than One Graphic If a test questionhas more than one table, graph, diagram, or draw-ing with it, use them all. If you answer based onjust one graphic, you’ve probably missed an impor-tant piece of information. For questions 5-7 above,make sure that you accurately analyzed both graph-ics before answering the questions.

Page From a Student’s Laboratory Notebook

Step Notes

Observation Carbonated beverages taste fizzier(more gassy) when they are warm than when they are cold. (Carbonatedbeverages are fizzy because they contain dissolved carbon dioxide gas.)

Hypothesis At higher temperatures, greateramounts of carbon dioxide gas will dissolve in a liquid. This is the same relationship between temperature and solubility seen with solids.

Experiment Measure the mass of carbon dioxide(CO2) in different samples of the same carbonated beverage at differenttemperatures.

Data Analysis See graph below.

Conclusion ?

0.35

0.30

0.25

0.20

0.15

0.100 5 10 15 20 25

Mass of CO2 Dissolved ina Carbonated Beverage

Temperature (˚C)

Mas

s o

f C

O2

(g)

Standardized Test Practice1. d 6. a2. c 7. a3. a4. b5. c

Thinking Critically35. It has been supported by

many experiments but stillrelies on further experi-ments for support. It doesnot describe a law ofnature that always occurs,such as gravity.

36. microscopic because itcannot be seen withhuman eyes

37. Data obtained testing anincorrect hypothesisprovides useful information.

38. The hypothesis might saythat the new fertilizerincreases the number ofbeans produced by eachbean plant. The proceduremight be to have threegroups of bean plants, onegroup with no fertilizer,one group with the un-improved fertilizer, and theother group with the newfertilizer. The independentvariable would be the useof fertilizer. The dependentvariable would be thenumber of beans producedby each plant. Constantsare the amount of lightand water received by eachplant. The control would bethe plants that received nofertilizer.

39. The qualitative statementsare that air quality is poorand that people shouldspend little time outside.Quantitative statementsinclude that visibility is onlya quarter mile and that thepollutants will rise above0.085 ppm in the nexteight-hour average.

40. Answers will vary but mightinclude environmental,biochemistry, and organic,analytical, inorganic, andbiochemistry, respectively.

CHAPTER 1 ASSESSMENT

Pages 22–232(A), 3(A), 3(C), 4(A)

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