BasicChemistry—FinalExam 1

Name:________________________________

Studentnumber:_______________________

AutumnSemester

BasicChemistryforEngineering/FundamentalInorganicChemistry

FinalExam

2February2015

Time:60minutes

Instructions:Answerany4questionsoutof5possiblequestions.Youmayanswermorethan4questionsifyouwish.Yourmarkswillbetakenfromyourtop4questions.Showallrelevantworking.Writeallanswersandfinalworkinginpen.Giveyouranswerstoanappropriatenumberofsignificantfigures.9pagesincluding:1toppage,1datapage,1periodictable,5questionpages,1pageforroughworkingHandinallpagesattheendoftheexam.Permissiblematerials:Calculator.EnglishorEnglishbilingualDictionary.

BasicChemistry—FinalExam 2

EquationsandData

Avagadronumber6.022x1023pV=nRTwherep=pressure,V=volume,n=no.ofmoles,R=idealgasconstantT=temperatureR=8.3144JK–1mol–1orR=0.082057LatmK–1mol–1Totalheatreleased/gainedbyreaction=∑∆Hfproducts–∑∆HfreactantsEnthalpiesofformation∆HfH2O(g):–242kJmol–1∆HfCH4(g):–74.9kJmol–1∆HfCO2(g):–394kJmol–1Somecommonmetalsalts:FeCl3,MgSO4,ZnSO4,CaCO3Benzylacetatepropertiesat25°CMaximumsolubilityinwater:0.31gml–1Densityofpureliquid:1.05gml–1.Commonunitcells

simple cubic body centred cubic face centred cubic

BasicChemistry—FinalExam 3

BasicChemistry—FinalExam 4

Question1A)Lookatthephasediagramright.

ii)Steelismadebydissolvingsmallcarbonatoms

intotheironcrystal.Whichoftheunitcellsonthe

phasediagramcandissolvethemostcarbon?

Why?

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[2]

iii)Roughlywhatisthebesttemperaturerangeformakinghigh-carbonsteel?

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[2]

B)i)Aninventorclaimsthatsolidsodiumchloride(NaCl)willbeagoodconductorof

electricitybecausesodiumisametal.IshecorrectaboutNaCl?Why?

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[2]

ii)Explainthemostcommonchoiceofmaterialsforthefollowingapplicationsintermsof

theirionic/molecularproperties:

Coffeemugs:material_____________________

Why?_____________________________________________________________________________________________________

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Gardeningtools:material_____________________

Why?_____________________________________________________________________________________________________

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[4]

—

—

—

—

—

— — — — — — — — —

T/°C

P/atm

1000

1500

2000

2500

3000

10 –1210 –1010 –8 10 –6 10 –4 10 –2 1.0 10 100

solid (BCC)

solid (FCC)

solid (BCC)

liquidvapour

BasicChemistry—FinalExam 5

Question2

A)Benzylacetate(C9H10O2)isaliquidusedasstrawberryflavouringinfoodproducts.

i)Whatisthemolarityofasaturatedsolution?

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[2]

ii)Whatisthepercentagebyvolumeofasaturatedsolution?

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[2]

iii)Afoodtechnicianstoressaturatedbenzylacetatesolutioninarefrigeratorbutcomesback

thenextdaytofindsmalldropsofanoilyliquidatthebottomoftheflask.Whathas

happened?

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[2]

B)Onemethodofproducingdrinkingwaterfromseawateristouseelectricitytopullions

outofthewaterthroughamembrane.

i)Thisprocessiscalled‘reverseosmosis’.Why?

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[2]

Reverseosmosisproducestwooutputstreamsofwater:drinkingwaterandwastewater.

ii)Explainatleasttwodifferencesinthephysicalpropertiesoftheoutputstreams.

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[2]

BasicChemistry—FinalExam 6

Question3

A)Labelthefollowingcasesasbeing‘open’or‘closed’whenapplyingthelawsof

thermodynamics.Explainyourreasoning.

i)Acarengineobservedoverseveralminutes.

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[2]

iii)Asealed,insulatedflask,observedoverthreedays.

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[2]

B)Hydrogengas(H2)isanewfuelforcars.

i)Calculatetheheatreleased,permoleofH2,inthereaction2H2+O2⟶2H2O.

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[1]

ii)Calculatetheheatreleased,permoleofCH4,inthereactionCH4+2O2⟶CO2+2H2O.

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[1]

iii)OfH2andCH4,whichfuelproducesthemostenergyfromafull25Lgastank?Why?

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[3]

iv)Fuelcellsrequireaplatinumcatalysttoproduceelectricityefficiently.Brieflyexplainone

reasonwhyacatalystisnecessary.

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[1]

BasicChemistry—FinalExam 7

Question4

A)i)Explainthedifferencebetweenanelectrolyticcellandavoltaiccell.

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[2]

ii)Drawanapparatusforplatinganironnailwithzinc(Zn)metal.Labelallnecessary

components.

[6]

iii)Givetworeasonsthezincplatingwillprotectthenailfromcorrosion.

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[2]

BasicChemistry—FinalExam 8

Question5

A)Achemistissynthesisingamoleculeusingthefollowingreactants:

Writetheletterofthefunctionalgroupthatisexpected…

i)tomaketheproductflatandrigid.___

ii)toactasabase.___

iii)towithdrawelectronsbyaninductiveeffect.___

iv)toallowextraatoms/moleculestobeaddedtotheproductlater.__

[4]

v)Whichfunctionalgroupsdoyouexpecttoreacttogether?Why?

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[2]

vi)Thechemistwantstoorderthereactantsfromasupplierbuttheir

catalogueshowsmaleicacidasthediagramontheright.Isthissuitable

forthechemist’sreaction?Why?

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[2]

B)

Drawtwoisomersofthefollowingmolecule.

[2]

NO2

NH2

HO OH

OO

+ product

a d

ec

b

p-nitroaniline maleic acid

HO

O

O

HO

maleic acid

HF

BasicChemistry—FinalExam 9

RoughWorking