CHAPTERc 1
AN INTRODUCTION TO CHEMISTRY
c c c
SOLUTIONScTOcREVIEWcQUESTIONS
1. (a)c c c Achypothesisciscactentativecexplanationcofccertaincfactsctocprovidecacbasiscforcf
urthercexperimentation.cActheoryciscancexplanationcofcthecgeneralcprinciplesco
fccertaincphenomenacwithcconsiderablecevidencectocsupportcit.
(b) Actheoryciscancexplanationcofcthecgeneralcprinciplescofccertaincphenomenacwithcc
onsiderablecevidencectocsupportcit.cAcscientificclawciscacsimplecstatementcofcnat
uralcphenomenactocwhichcnocexceptionscarecknowncundercthecgivencconditions.
2. (a) hypothesis
(b) hypothesis
(c) observation
(d) theory
(e) observation
(f) scientificclaw
3. (a) Acliquidchascacdefinitecvolumecbutcnotcacdefinitecshape.
(b) Acgaschascancindefinitecvolumecandchighccompressibility.
(c) Acsolidchascacdefinitecshape.
(d) Acliquidchascancindefinitecshapecandcslightccompressibility.
4. Accrystallinecsolidchascacregular,crepeating,cthree-
dimensional,cgeometriccpattern.cAncamorphouscsolidcdoescnot.
(a) Acsolidcthatchascacregular,crepeatingcpatternciscaccrystallinecsolid.
(b) Ac plasticc solidc isc amorphous.
(c) Acsolidcthatchascnocregularcrepeatingcpatternciscamorphous.
(d) Glassciscancamorphouscsolid.
(e) Goldc isc ac crystallinec solid.
5. Acphaseciscachomogeneouscpartcofcacsystemcseparatedcfromcothercpartscbycacphysicalcb
oundary.
6. Therecarecsixcphasescpresent.
7. Anothercnamecforcachomogeneouscmixtureciscsolution.
8. Alcohol,cmercury,candcwatercarectheconlycliquidscincthectablecwhichcarecnotcmixtures.c
Mercuryciscancelement;calcoholcandcwatercareccompounds.
1
, –c Chapterc 1c –
9. Aircisctheconlycgascmixturecfoundcincthectable.cThecothercgasescarecelementscorcc
ompounds.
10. Threecphasescarecpresentcwithincthecbottle;csolidcandcliquidcarecobservedcvisually,c
whilecgasciscdetectedcbycthecimmediatecodor.
11. Thec systemc isc heterogeneousc asc threec phasesc arec present.
12. Acsystemccontainingconlyconecsubstanceciscnotcnecessarilychomogeneous.cTwoc
phasescmaycbecpresent.cExample:cicecincwater.
13. Acsystemccontainingctwocorcmorecsubstancesciscnotcnecessarilycheterogeneous.cIncacs
olutionconlyconecphaseciscpresent.cExamples:csugarcdissolvedcincwater,cdilutecsulfur
iccacid.
14. Homogeneouscmixturesccontainconlyconecphase,cwhilecheterogeneouscmixturesc
containctwocorcmorecphases.
15. (a)csugar,caccompoundcandc(c)cgold,cancelement
16. Usingcthecstepscofcthecscientificcmethodctochelpcdeterminecwhycyourccellcphonechascs
toppedcworking.
(a) Observation: Myccellcphonechascstoppedcworking.
(b) Hypothesis: Icthinkcthatcthecbatterycneedsctocbecrecharged.
(c) Experiment: Plugcincthecphonectocrechargecthecbatterycandcallow
sufficientctimecforcthecbatteryctocfullycrecharge.cTurncthecpho
necbackcon.cThecphonecnowcworkscagain.
(d) Theory: Thecbatterycincthecphonechascaclimitedcchargectimecand
needsctocbecrechargedconcacregularcbasiscincorderctockeepcitcin
cworking corder.
2
, –c Chapterc 1c –
SOLUTIONSc TOc EXERCISES
1. Twocstatescarecpresent;csolidcandcgas.
2. Twocstatescarecpresent;csolidcandcliquid.
3. Thecphotocrepresentscacheterogeneouscmixture.
4. Thec maplec leafc representsc ac heterogeneousc mixture.
5. (a) homogeneous
(b) heterogeneous
(c) heterogeneous
(d) heterogeneous
6. (a) homogeneous
(b) homogeneous
(c) heterogeneous
(d) heterogeneous
7. Typicalc answersc couldc be
Substance MaincorcActivecIngredient
chocolatec syrup highcfructoseccorncsyrup
margarine vegetablecoilcblend
nondairyc creamer corncsyrupcsolids
beefcbouillon salt
toothpaste sodiumcfluoride
antibacterialcsoap triclocarban
firstcaidcspray lidocainec HCl
sunblockclotion ethylhexylcp-methoxycinnamate
8. Thecstepscofcthecscientificcmethodccancbecusedctocpredictcthecoutcomecofcthecsemesterci
ncthecfollowingcway:
(a) Collectcthecfactscorcdata.cTheycincludecthecnumbercofcclassescyouchavecenrolle
dcin,cthecamountcofctimecyoucwillcgivectoceachcclass,cthecnumbercofchourscrequi
redcforcyourcoffccampuscjob,candcthecamountcofctimecforcsocialc activities.
(b) Formulatecachypotheses.cYoucpredictcthatcthecamountcofctimecyouchavecallocat
edceachcweekcforcclasscworkcwillcbecsufficientctocresultcincgoodcgradescatcthecendc
ofcthecsemester.
(c) Plancandcdocadditionalcexperimentsctoctestcthechypothesis.cIncthecfirstctwoc
weekscofcthecsemesterckeepcacrecordcofcyourcperformancecinceachcclass,cin
cludingcgradesconchomework,cquizzes,candcexams.
(d) Modifycthechypothesis.cIfcyourcgradescincanycclasscarecnotcgood,cyourchypot
hesiscwascincorrect.cItcwillcbecnecessaryctocincreasecthecamountcofctimecallocat
edctocthatcclass.
3
, –c Chapterc 1c –
9. (a) water,cacpurecsubstance
(b) chickencstock,cacmixture
(c) salt,cacpurecsubstance
(d) mustardcflour,cacmixture
10. Hypothesisc–
cThecsoup cis cnotcacgoodcsourcecofcnutrition cbecausecitccontainsc12cgramscofcfatcp
ercserving.
Testc–
cSearch cforcthecnumber cofcgrams cofcfatcpercdaycrecommendedcforcan cadult. cComparec
thiscnumberctocthecgramscpercfatconctheclabel.
11. Observationsc –
Calciteccrystalschavecthecabilityctocreflectclightcaroundcancobjectcrenderingcitc“uns
eeable”.
“Invisibilityccloaks”cworkconlycwithclaserclightcaimedcdirectlycatctheccrystal.
Hypothesesc –
Ifclargerccrystalscwerecused,clargercobjectsccouldcbechidden.cTh
esec“invisibilityccloaks”cwillcimprovecincthecfuture.
12. (a),c(b),cPicturec(2)cbestcrepresentscachomogeneouscmixture.cPicturesc(1)candc(c)c(3)cs
howcheterogeneouscmixtures,candcpicturec(4)cdoescnotcshowcacmixture,casconlyconecsp
eciesciscpresent.
Picturec(1)clikelycshowscaccompound,casconecofctheccomponentscofcthecmixtureciscmad
ecupcofcmorecthanconectypecofc“ball”.cPicturec(2)cshowscaccomponentcwithcmorecthanco
necpart,cbutcthecpartscseemcidentical,candcthereforecitccouldcbecrepresentingcacdiatomic
cmolecule.
13. (a) twocphases,csolidcandcgas
(b) twocphases,cliquidcandcgas
(c) twocphases,csolidcandcliquid
4
AN INTRODUCTION TO CHEMISTRY
c c c
SOLUTIONScTOcREVIEWcQUESTIONS
1. (a)c c c Achypothesisciscactentativecexplanationcofccertaincfactsctocprovidecacbasiscforcf
urthercexperimentation.cActheoryciscancexplanationcofcthecgeneralcprinciplesco
fccertaincphenomenacwithcconsiderablecevidencectocsupportcit.
(b) Actheoryciscancexplanationcofcthecgeneralcprinciplescofccertaincphenomenacwithcc
onsiderablecevidencectocsupportcit.cAcscientificclawciscacsimplecstatementcofcnat
uralcphenomenactocwhichcnocexceptionscarecknowncundercthecgivencconditions.
2. (a) hypothesis
(b) hypothesis
(c) observation
(d) theory
(e) observation
(f) scientificclaw
3. (a) Acliquidchascacdefinitecvolumecbutcnotcacdefinitecshape.
(b) Acgaschascancindefinitecvolumecandchighccompressibility.
(c) Acsolidchascacdefinitecshape.
(d) Acliquidchascancindefinitecshapecandcslightccompressibility.
4. Accrystallinecsolidchascacregular,crepeating,cthree-
dimensional,cgeometriccpattern.cAncamorphouscsolidcdoescnot.
(a) Acsolidcthatchascacregular,crepeatingcpatternciscaccrystallinecsolid.
(b) Ac plasticc solidc isc amorphous.
(c) Acsolidcthatchascnocregularcrepeatingcpatternciscamorphous.
(d) Glassciscancamorphouscsolid.
(e) Goldc isc ac crystallinec solid.
5. Acphaseciscachomogeneouscpartcofcacsystemcseparatedcfromcothercpartscbycacphysicalcb
oundary.
6. Therecarecsixcphasescpresent.
7. Anothercnamecforcachomogeneouscmixtureciscsolution.
8. Alcohol,cmercury,candcwatercarectheconlycliquidscincthectablecwhichcarecnotcmixtures.c
Mercuryciscancelement;calcoholcandcwatercareccompounds.
1
, –c Chapterc 1c –
9. Aircisctheconlycgascmixturecfoundcincthectable.cThecothercgasescarecelementscorcc
ompounds.
10. Threecphasescarecpresentcwithincthecbottle;csolidcandcliquidcarecobservedcvisually,c
whilecgasciscdetectedcbycthecimmediatecodor.
11. Thec systemc isc heterogeneousc asc threec phasesc arec present.
12. Acsystemccontainingconlyconecsubstanceciscnotcnecessarilychomogeneous.cTwoc
phasescmaycbecpresent.cExample:cicecincwater.
13. Acsystemccontainingctwocorcmorecsubstancesciscnotcnecessarilycheterogeneous.cIncacs
olutionconlyconecphaseciscpresent.cExamples:csugarcdissolvedcincwater,cdilutecsulfur
iccacid.
14. Homogeneouscmixturesccontainconlyconecphase,cwhilecheterogeneouscmixturesc
containctwocorcmorecphases.
15. (a)csugar,caccompoundcandc(c)cgold,cancelement
16. Usingcthecstepscofcthecscientificcmethodctochelpcdeterminecwhycyourccellcphonechascs
toppedcworking.
(a) Observation: Myccellcphonechascstoppedcworking.
(b) Hypothesis: Icthinkcthatcthecbatterycneedsctocbecrecharged.
(c) Experiment: Plugcincthecphonectocrechargecthecbatterycandcallow
sufficientctimecforcthecbatteryctocfullycrecharge.cTurncthecpho
necbackcon.cThecphonecnowcworkscagain.
(d) Theory: Thecbatterycincthecphonechascaclimitedcchargectimecand
needsctocbecrechargedconcacregularcbasiscincorderctockeepcitcin
cworking corder.
2
, –c Chapterc 1c –
SOLUTIONSc TOc EXERCISES
1. Twocstatescarecpresent;csolidcandcgas.
2. Twocstatescarecpresent;csolidcandcliquid.
3. Thecphotocrepresentscacheterogeneouscmixture.
4. Thec maplec leafc representsc ac heterogeneousc mixture.
5. (a) homogeneous
(b) heterogeneous
(c) heterogeneous
(d) heterogeneous
6. (a) homogeneous
(b) homogeneous
(c) heterogeneous
(d) heterogeneous
7. Typicalc answersc couldc be
Substance MaincorcActivecIngredient
chocolatec syrup highcfructoseccorncsyrup
margarine vegetablecoilcblend
nondairyc creamer corncsyrupcsolids
beefcbouillon salt
toothpaste sodiumcfluoride
antibacterialcsoap triclocarban
firstcaidcspray lidocainec HCl
sunblockclotion ethylhexylcp-methoxycinnamate
8. Thecstepscofcthecscientificcmethodccancbecusedctocpredictcthecoutcomecofcthecsemesterci
ncthecfollowingcway:
(a) Collectcthecfactscorcdata.cTheycincludecthecnumbercofcclassescyouchavecenrolle
dcin,cthecamountcofctimecyoucwillcgivectoceachcclass,cthecnumbercofchourscrequi
redcforcyourcoffccampuscjob,candcthecamountcofctimecforcsocialc activities.
(b) Formulatecachypotheses.cYoucpredictcthatcthecamountcofctimecyouchavecallocat
edceachcweekcforcclasscworkcwillcbecsufficientctocresultcincgoodcgradescatcthecendc
ofcthecsemester.
(c) Plancandcdocadditionalcexperimentsctoctestcthechypothesis.cIncthecfirstctwoc
weekscofcthecsemesterckeepcacrecordcofcyourcperformancecinceachcclass,cin
cludingcgradesconchomework,cquizzes,candcexams.
(d) Modifycthechypothesis.cIfcyourcgradescincanycclasscarecnotcgood,cyourchypot
hesiscwascincorrect.cItcwillcbecnecessaryctocincreasecthecamountcofctimecallocat
edctocthatcclass.
3
, –c Chapterc 1c –
9. (a) water,cacpurecsubstance
(b) chickencstock,cacmixture
(c) salt,cacpurecsubstance
(d) mustardcflour,cacmixture
10. Hypothesisc–
cThecsoup cis cnotcacgoodcsourcecofcnutrition cbecausecitccontainsc12cgramscofcfatcp
ercserving.
Testc–
cSearch cforcthecnumber cofcgrams cofcfatcpercdaycrecommendedcforcan cadult. cComparec
thiscnumberctocthecgramscpercfatconctheclabel.
11. Observationsc –
Calciteccrystalschavecthecabilityctocreflectclightcaroundcancobjectcrenderingcitc“uns
eeable”.
“Invisibilityccloaks”cworkconlycwithclaserclightcaimedcdirectlycatctheccrystal.
Hypothesesc –
Ifclargerccrystalscwerecused,clargercobjectsccouldcbechidden.cTh
esec“invisibilityccloaks”cwillcimprovecincthecfuture.
12. (a),c(b),cPicturec(2)cbestcrepresentscachomogeneouscmixture.cPicturesc(1)candc(c)c(3)cs
howcheterogeneouscmixtures,candcpicturec(4)cdoescnotcshowcacmixture,casconlyconecsp
eciesciscpresent.
Picturec(1)clikelycshowscaccompound,casconecofctheccomponentscofcthecmixtureciscmad
ecupcofcmorecthanconectypecofc“ball”.cPicturec(2)cshowscaccomponentcwithcmorecthanco
necpart,cbutcthecpartscseemcidentical,candcthereforecitccouldcbecrepresentingcacdiatomic
cmolecule.
13. (a) twocphases,csolidcandcgas
(b) twocphases,cliquidcandcgas
(c) twocphases,csolidcandcliquid
4
