CHAPTERk 1
AN INTRODUCTION TO CHEMISTRY
k k k
SOLUTIONSkTOkREVIEWkQUESTIONS
1. (a)k k Akhypothesiskiskaktentativekexplanationkofkcertainkfactsktokprovidekakbasiskforkf
urtherkexperimentation.kAktheorykiskankexplanationkofkthekgeneralkprinciplesko
fkcertainkphenomenakwithkconsiderablekevidencektoksupportkit.
(b) Aktheorykiskankexplanationkofkthekgeneralkprincipleskofkcertainkphenomenakwithk
considerablekevidencektoksupportkit.kAkscientificklawkiskaksimplekstatementkofkn
aturalkphenomenaktokwhichknokexceptionskarekknownkunderkthekgivenkconditio
ns.
2. (a) hypothesis
(b) hypothesis
(c) observation
(d) theory
(e) observation
(f) scientificklaw
3. (a) Akliquidkhaskakdefinitekvolumekbutknotkakdefinitekshape.
(b) Akgaskhaskankindefinitekvolumekandkhighkcompressibility.
(c) Aksolidkhaskakdefinitekshape.
(d) Akliquidkhaskankindefinitekshapekandkslightkcompressibility.
4. Akcrystallineksolidkhaskakregular,krepeating,kthree-
dimensional,kgeometrickpattern.kAnkamorphousksolidkdoesknot.
(a) Aksolidkthatkhaskakregular,krepeatingkpatternkiskakcrystallineksolid.
(b) Ak plastick solidk isk amorphous.
(c) Aksolidkthatkhasknokregularkrepeatingkpatternkiskamorphous.
(d) Glasskiskankamorphousksolid.
(e) Goldk isk ak crystallinek solid.
5. Akphasekiskakhomogeneouskpartkofkaksystemkseparatedkfromkotherkpartskbykakphysicalk
boundary.
6. Therekareksixkphaseskpresent.
7. Anotherknamekforkakhomogeneouskmixturekisksolution.
8. Alcohol,kmercury,kandkwaterkarekthekonlykliquidskinkthektablekwhichkareknotkmixtures.k
Mercurykiskankelement;kalcoholkandkwaterkarekcompounds.
1
, –k Chapterk 1k –
9. Airkiskthekonlykgaskmixturekfoundkinkthektable.kThekotherkgaseskarekelementskork
compounds.
10. Threekphaseskarekpresentkwithinkthekbottle;ksolidkandkliquidkarekobservedkvisually,k
whilekgaskiskdetectedkbykthekimmediatekodor.
11. Thek systemk isk heterogeneousk ask threek phasesk arek present.
12. Aksystemkcontainingkonlykoneksubstancekisknotknecessarilykhomogeneous.kTwok
phaseskmaykbekpresent.kExample:kicekinkwater.
13. Aksystemkcontainingktwokorkmoreksubstanceskisknotknecessarilykheterogeneous.kInkak
solutionkonlykonekphasekiskpresent.kExamples:ksugarkdissolvedkinkwater,kdiluteksulf
urickacid.
14. Homogeneouskmixtureskcontainkonlykonekphase,kwhilekheterogeneouskmixturesk
containktwokorkmorekphases.
15. (a)ksugar,kakcompoundkandk(c)kgold,kankelement
16. Usingkthekstepskofkthekscientifickmethodktokhelpkdeterminekwhykyourkcellkphonekhask
stoppedkworking.
(a) Observation: Mykcellkphonekhaskstoppedkworking.
(b) Hypothesis: Ikthinkkthatkthekbatterykneedsktokbekrecharged.
(c) Experiment: Plugkinkthekphonektokrechargekthekbatterykandkallow
sufficientktimekforkthekbatteryktokfullykrecharge.kTurnkthekph
onekbackkon.kThekphoneknowkworkskagain.
(d) Theory: Thekbatterykinkthekphonekhaskaklimitedkchargektimekand
needsktokbekrechargedkonkakregularkbasiskinkorderktokkeepkitki
nkworkingkorder.
2
, –k Chapterk 1k –
SOLUTIONSk TOk EXERCISES
1. Twokstateskarekpresent;ksolidkandkgas.
2. Twokstateskarekpresent;ksolidkandkliquid.
3. Thekphotokrepresentskakheterogeneouskmixture.
4. Thek maplek leafk representsk ak heterogeneousk mixture.
5. (a) homogeneous
(b) heterogeneous
(c) heterogeneous
(d) heterogeneous
6. (a) homogeneous
(b) homogeneous
(c) heterogeneous
(d) heterogeneous
7. Typicalk answersk couldk be
Substance MainkorkActivekIngredient
chocolatek syrup highkfructosekcornksyrup
margarine vegetablekoilkblend
nondairyk creamer cornksyrupksolids
beefkbouillon salt
toothpaste sodiumkfluoride
antibacterialksoap triclocarban
firstkaidkspray lidocainek HCl
sunblockklotion ethylhexylkp-methoxycinnamate
8. Thekstepskofkthekscientifickmethodkcankbekusedktokpredictkthekoutcomekofktheksemesterki
nkthekfollowingkway:
(a) Collectkthekfactskorkdata.kTheykincludektheknumberkofkclasseskyoukhavekenroll
edkin,kthekamountkofktimekyoukwillkgivektokeachkclass,ktheknumberkofkhourskre
quiredkforkyourkoffkcampuskjob,kandkthekamountkofktimekforksocialk activities.
(b) Formulatekakhypotheses.kYoukpredictkthatkthekamountkofktimekyoukhavekallocat
edkeachkweekkforkclasskworkkwillkbeksufficientktokresultkinkgoodkgradeskatkthekend
kofktheksemester.
(c) Plankandkdokadditionalkexperimentsktoktestkthekhypothesis.kInkthekfirstktwok
weekskofktheksemesterkkeepkakrecordkofkyourkperformancekinkeachkclass,kin
cludingkgradeskonkhomework,kquizzes,kandkexams.
(d) Modifykthekhypothesis.kIfkyourkgradeskinkanykclasskareknotkgood,kyourkhypot
hesiskwaskincorrect.kItkwillkbeknecessaryktokincreasekthekamountkofktimekalloca
tedktokthatkclass.
3
, –k Chapterk 1k –
9. (a) water,kakpureksubstance
(b) chickenkstock,kakmixture
(c) salt,kakpureksubstance
(d) mustardkflour,kakmixture
10. Hypothesisk–
kTheksoup kis knot kakgoodksourcekofknutrition kbecause kitkcontains k12 kgramskofkfatk
perkserving.
Testk–
kSearch kforktheknumber kofkgrams kofkfat kperkday krecommended kforkan kadult. kCompar
ekthisknumberktokthekgramskperkfatkonktheklabel.
11. Observationsk –
Calcitekcrystalskhavekthekabilityktokreflectklightkaroundkankobjectkrenderingkitk“u
nseeable”.
“Invisibilitykcloaks”kworkkonlykwithklaserklightkaimedkdirectlykatkthekcrystal.
Hypothesesk –
Ifklargerkcrystalskwerekused,klargerkobjectskcouldkbekhidden.kTh
esek“invisibilitykcloaks”kwillkimprovekinkthekfuture.
12. (a),k(b),kPicturek(2)kbestkrepresentskakhomogeneouskmixture.kPicturesk(1)kandk(c)k(3)k
showkheterogeneouskmixtures,kandkpicturek(4)kdoesknotkshowkakmixture,kaskonlykonek
specieskiskpresent.
Picturek(1)klikelykshowskakcompound,kaskonekofkthekcomponentskofkthekmixturekiskma
dekupkofkmorekthankonektypekofk“ball”.kPicturek(2)kshowskakcomponentkwithkmorekthan
konekpart, kbut kthekparts kseem kidentical, kand kthereforekit kcould kbekrepresenting kakdiato
mickmolecule.
13. (a) twokphases,ksolidkandkgas
(b) twokphases,kliquidkandkgas
(c) twokphases,ksolidkandkliquid
4
AN INTRODUCTION TO CHEMISTRY
k k k
SOLUTIONSkTOkREVIEWkQUESTIONS
1. (a)k k Akhypothesiskiskaktentativekexplanationkofkcertainkfactsktokprovidekakbasiskforkf
urtherkexperimentation.kAktheorykiskankexplanationkofkthekgeneralkprinciplesko
fkcertainkphenomenakwithkconsiderablekevidencektoksupportkit.
(b) Aktheorykiskankexplanationkofkthekgeneralkprincipleskofkcertainkphenomenakwithk
considerablekevidencektoksupportkit.kAkscientificklawkiskaksimplekstatementkofkn
aturalkphenomenaktokwhichknokexceptionskarekknownkunderkthekgivenkconditio
ns.
2. (a) hypothesis
(b) hypothesis
(c) observation
(d) theory
(e) observation
(f) scientificklaw
3. (a) Akliquidkhaskakdefinitekvolumekbutknotkakdefinitekshape.
(b) Akgaskhaskankindefinitekvolumekandkhighkcompressibility.
(c) Aksolidkhaskakdefinitekshape.
(d) Akliquidkhaskankindefinitekshapekandkslightkcompressibility.
4. Akcrystallineksolidkhaskakregular,krepeating,kthree-
dimensional,kgeometrickpattern.kAnkamorphousksolidkdoesknot.
(a) Aksolidkthatkhaskakregular,krepeatingkpatternkiskakcrystallineksolid.
(b) Ak plastick solidk isk amorphous.
(c) Aksolidkthatkhasknokregularkrepeatingkpatternkiskamorphous.
(d) Glasskiskankamorphousksolid.
(e) Goldk isk ak crystallinek solid.
5. Akphasekiskakhomogeneouskpartkofkaksystemkseparatedkfromkotherkpartskbykakphysicalk
boundary.
6. Therekareksixkphaseskpresent.
7. Anotherknamekforkakhomogeneouskmixturekisksolution.
8. Alcohol,kmercury,kandkwaterkarekthekonlykliquidskinkthektablekwhichkareknotkmixtures.k
Mercurykiskankelement;kalcoholkandkwaterkarekcompounds.
1
, –k Chapterk 1k –
9. Airkiskthekonlykgaskmixturekfoundkinkthektable.kThekotherkgaseskarekelementskork
compounds.
10. Threekphaseskarekpresentkwithinkthekbottle;ksolidkandkliquidkarekobservedkvisually,k
whilekgaskiskdetectedkbykthekimmediatekodor.
11. Thek systemk isk heterogeneousk ask threek phasesk arek present.
12. Aksystemkcontainingkonlykoneksubstancekisknotknecessarilykhomogeneous.kTwok
phaseskmaykbekpresent.kExample:kicekinkwater.
13. Aksystemkcontainingktwokorkmoreksubstanceskisknotknecessarilykheterogeneous.kInkak
solutionkonlykonekphasekiskpresent.kExamples:ksugarkdissolvedkinkwater,kdiluteksulf
urickacid.
14. Homogeneouskmixtureskcontainkonlykonekphase,kwhilekheterogeneouskmixturesk
containktwokorkmorekphases.
15. (a)ksugar,kakcompoundkandk(c)kgold,kankelement
16. Usingkthekstepskofkthekscientifickmethodktokhelpkdeterminekwhykyourkcellkphonekhask
stoppedkworking.
(a) Observation: Mykcellkphonekhaskstoppedkworking.
(b) Hypothesis: Ikthinkkthatkthekbatterykneedsktokbekrecharged.
(c) Experiment: Plugkinkthekphonektokrechargekthekbatterykandkallow
sufficientktimekforkthekbatteryktokfullykrecharge.kTurnkthekph
onekbackkon.kThekphoneknowkworkskagain.
(d) Theory: Thekbatterykinkthekphonekhaskaklimitedkchargektimekand
needsktokbekrechargedkonkakregularkbasiskinkorderktokkeepkitki
nkworkingkorder.
2
, –k Chapterk 1k –
SOLUTIONSk TOk EXERCISES
1. Twokstateskarekpresent;ksolidkandkgas.
2. Twokstateskarekpresent;ksolidkandkliquid.
3. Thekphotokrepresentskakheterogeneouskmixture.
4. Thek maplek leafk representsk ak heterogeneousk mixture.
5. (a) homogeneous
(b) heterogeneous
(c) heterogeneous
(d) heterogeneous
6. (a) homogeneous
(b) homogeneous
(c) heterogeneous
(d) heterogeneous
7. Typicalk answersk couldk be
Substance MainkorkActivekIngredient
chocolatek syrup highkfructosekcornksyrup
margarine vegetablekoilkblend
nondairyk creamer cornksyrupksolids
beefkbouillon salt
toothpaste sodiumkfluoride
antibacterialksoap triclocarban
firstkaidkspray lidocainek HCl
sunblockklotion ethylhexylkp-methoxycinnamate
8. Thekstepskofkthekscientifickmethodkcankbekusedktokpredictkthekoutcomekofktheksemesterki
nkthekfollowingkway:
(a) Collectkthekfactskorkdata.kTheykincludektheknumberkofkclasseskyoukhavekenroll
edkin,kthekamountkofktimekyoukwillkgivektokeachkclass,ktheknumberkofkhourskre
quiredkforkyourkoffkcampuskjob,kandkthekamountkofktimekforksocialk activities.
(b) Formulatekakhypotheses.kYoukpredictkthatkthekamountkofktimekyoukhavekallocat
edkeachkweekkforkclasskworkkwillkbeksufficientktokresultkinkgoodkgradeskatkthekend
kofktheksemester.
(c) Plankandkdokadditionalkexperimentsktoktestkthekhypothesis.kInkthekfirstktwok
weekskofktheksemesterkkeepkakrecordkofkyourkperformancekinkeachkclass,kin
cludingkgradeskonkhomework,kquizzes,kandkexams.
(d) Modifykthekhypothesis.kIfkyourkgradeskinkanykclasskareknotkgood,kyourkhypot
hesiskwaskincorrect.kItkwillkbeknecessaryktokincreasekthekamountkofktimekalloca
tedktokthatkclass.
3
, –k Chapterk 1k –
9. (a) water,kakpureksubstance
(b) chickenkstock,kakmixture
(c) salt,kakpureksubstance
(d) mustardkflour,kakmixture
10. Hypothesisk–
kTheksoup kis knot kakgoodksourcekofknutrition kbecause kitkcontains k12 kgramskofkfatk
perkserving.
Testk–
kSearch kforktheknumber kofkgrams kofkfat kperkday krecommended kforkan kadult. kCompar
ekthisknumberktokthekgramskperkfatkonktheklabel.
11. Observationsk –
Calcitekcrystalskhavekthekabilityktokreflectklightkaroundkankobjectkrenderingkitk“u
nseeable”.
“Invisibilitykcloaks”kworkkonlykwithklaserklightkaimedkdirectlykatkthekcrystal.
Hypothesesk –
Ifklargerkcrystalskwerekused,klargerkobjectskcouldkbekhidden.kTh
esek“invisibilitykcloaks”kwillkimprovekinkthekfuture.
12. (a),k(b),kPicturek(2)kbestkrepresentskakhomogeneouskmixture.kPicturesk(1)kandk(c)k(3)k
showkheterogeneouskmixtures,kandkpicturek(4)kdoesknotkshowkakmixture,kaskonlykonek
specieskiskpresent.
Picturek(1)klikelykshowskakcompound,kaskonekofkthekcomponentskofkthekmixturekiskma
dekupkofkmorekthankonektypekofk“ball”.kPicturek(2)kshowskakcomponentkwithkmorekthan
konekpart, kbut kthekparts kseem kidentical, kand kthereforekit kcould kbekrepresenting kakdiato
mickmolecule.
13. (a) twokphases,ksolidkandkgas
(b) twokphases,kliquidkandkgas
(c) twokphases,ksolidkandkliquid
4
