ScienceOlympiad
EastsideInvitational
StevensonHighSchool
2017
ChemistryLab
Part1–WrittenExam
Part2–LabComponent
Readthedirectionsbelow.Donotstartthetestuntilyouhavebeeninstructedtodoso.
• Youmaywriteonthistest.
• Youmayseparatethistestintomultiplesections.
• Onlyanswersrecordedonthescantronwillbegraded.
• Youwillfindreferencepagesatthebeginningofthetestthatyoumayrefertoatanypointduring
thetestorlab.
• Allpagesofthistestmustbestapledtogetherandreturnedattheendofthetestingperiod.
TeamNumber:
___________
School/Team:
___________________________________________________________________________________________
StudentNames:
___________________________________________________________________________________________
ScienceOlympiad–ChemistryLab
Part1–WrittenTest
MultipleChoice–Selectthebestanswerforeachbelow.Besuretotransferyouranswerstothescantron.
1. Whichofthefollowingstatementsaboutgasesisnottrue?
a.
b.
c.
d.
e.
Gasescanbeeasilycompressed
Thedistancebetweengasmoleculesislarge
Gasescanformhomogenousmixtures
Gaseswillexpandtofilltheircontainer
Allgasesarecolorlessandodorlessunderstandardconditions
2. Agassampleatconstanttemperaturehasavolumeof250mLand3.50atm.Whatvolumewillthesample
occupyifthepressureischangedto1.55atm?
a.
b.
c.
d.
e.
111mL
217mL
565mL
1.36L
5.65L
3. Asealedballoonwillbreakifitsvolumereaches4.50L.At20°C,thevolumeoftheballoonis3.79L.At
whattemperaturewilltheballoonbreakifthepressurestaysthesame?
a.
b.
c.
d.
e.
17°C
24°C
26°C
51°C
75°C
4. Howmanymolesofagasoccupy2.67Lat2.3atmand25°C?
a.
b.
c.
d.
e.
2.5x10-3mol
0.030mol
0.25mol
3.0mol
4.0mol
5. Whichofthefollowinggaseswouldhavethehighestaveragemolecularspeedat25°C?
a. O2
b. N2
c. CO2
d. CH4
e. SF6
6. InthevanderWaalsequation,theconstants“a”and“b”are
a. Usedtocorrectforthefinitevolumeofgasmoleculesandtheattractiveforcesbetweengas
molecules
b. Equaltoeachotherforanyrealgas
c. UsedtocorrectforthedifferencebetweenCelsiusandKelvin
d. Equalto1foridealgases
e. Usedtocorrectforthefactthatcollisionsofgasmoleculesarenotreallycompletelyelastic
7. Thevaporpressureofaliquidwilldecreaseif
a. Thevolumeofthevaporabovetheliquidisincreased
b. Thevolumeoftheliquidisdecreased
c. Thetemperatureisdecreased
d. Thesurfaceareaoftheliquidisdecreased
e. Amorevolatileliquidisadded
8. Whichofthefollowingstatementsis/aretrue?
I.
Deviationsinthebehaviorofgasesfromtheideal-gasequationoccurbecausegasmoleculesoccupy
afinitevolumeinacontainer
II.
Deviationsinthebehaviorofgasesfromtheideal-gasequationoccurbecauseattractionsbetween
gasmoleculesexist
III.
Deviationsinthebehaviorofgasesfromtheideal-gasequationdecreasewithincreasing
temperature
a. Ionly
b. IIonly
c. IandII
d. IIandIII
e. I,II,andIII
9. Howmuchheatisrequiredtoconvert100gofwaterat40°Ctowatervaporat100°C?
a. 227kJ
b. 418kJ
c. 226kJ
d. 25.1kJ
e. 251kJ
10. Achemistusesacylinderwithapistonandgasinletvalve.Considerthefollowingchange:Injectan
additionalgasthroughthegasinletvalve.Whatwillbetheconsequencesforthepressureofthegasand
forthenumberofmolesofgaspresent?
a. Thepressureofthegaswilldecrease,andthenumberofmolesofgaspresentwilldecrease
b. Thepressureofthegaswillincrease,andthenumberofmolesofgaspresentwillincrease
c. Thepressureofthegaswilldecrease,andthenumberofmolesofgaspresentwillincrease
d. Therewillbenochangesinthepressureofthegasorinthenumberofmoles
e. Thenumberofmoleswillstaythesame,andthepressureofthegaswilldecrease
11. Accordingtotheideal-gasequation,whichofthefollowingstatementsistrue?
a. Ifgasesaremixed,thepartialpressureofeachlowersthepartialpressureoftheothers
b. ForBoyle’slawtoapply,agasmustbekeptatconstantpressure
c. Thevolumeofagasisnotchangedifitisheatedfrom0°Cto100°Candatthesamevolumeifthe
pressureisincreasedfrom750torrto850torr
d. Thevolumeofagasdoubleswhenthecentigradetemperaturedoublesifallothervariablesare
heldconstant
e. Thevolumeofagasdecreasesbyafactorof2whenthepressureisdoubledifallother
variablesareheldconstant
12. AtSTP,20.MicrolitersofO2contain5.4x1016molecules.Howmanymoleculesarein20.microlitersofN2?
a. 5.4x1015
b. 1.0x1016
c. 2.7x1016
d. 5.4x1016
13. Ablimpisfilledwith5000.Lofheliumat28.0°Cand99.7kPa.Whatisthemassofheliumused?
a. 797g
b. 810.g
c. 879g
d. 8.57x103g
14. WhatisthedensityofnitrogengasatSTP?
a. 0.62g/L
b. 1.14g/L
c. 1.25g/L
d. 2.03g/L
15. Findthevolumeofmethanethatwillproduce12Lofhydrogeninthereactionbelow.Assumetemperature
andpressureremainconstant.
CH4(g)+H2O(g)àCO(g)+H2(g)
a. 4.0L
b. 12L
c. 24L
d. 36L
16. Whatisthepartialpressureofoxygen,intorr,intheatmospherewhentheatmosphericpressureis760.0
torr?
ComponentsofAir
Nitrogen
Oxygen
Argon
a.
b.
c.
d.
e.
MoleFraction
0.781
0.209
0.010
159
430
601
720
760
17. Agasisheatedinasealedcontainer.Whichofthefollowingoccur?
a. Gaspressurerises
b. Gasdensitydecreases
c. Theaveragedistancebetweenmoleculesincreases
d. Alloftheabove
18. A__________________∆Hcorrespondstoa________________process.Selectallthataretrue.
a. Negative;endothermic
b. Negative;exothermic
c. Positive;exothermic
d. Positive;endothermic
e. Zero;exothermic
19. Anamountofheatequalto3500Jisreleasedfromasystem.Inaddition,1500Jofworkisdonebythe
systemonthesurroundings.Whatisthechangeininternalenergyofthesystem?
a. 1500J
b. 2000J
c. 3500J
d. 5000J
e. -5000J
20. ∆H°forthereactionbelowis-482kJ.Calculatetheheatreleasedwhen12.0gofCO(g)reactscompletely,
accordingtothefollowingchemicalequation:
2CO(g)+O2(g)à2CO2(g)
a. 2.89x103kJ
b. 206kJ
c. 103kJ
d. 65.7kJ
e. -482kJ
21. Whatisthespecificheatofironif13.5Jisrequiredtoraisethetemperatureofa10-gsampleby3K?
a. 0.45J/g-K
b. 2.22J/g-K
c. 4.05J/g-K
d. 45J/g-K
e. 405J/g-K
22. Forwhichofthespeciesinthefollowingchemicalreactionistheenthalpyofformationequaltozero?
2Co(s)+H2(g)+8PF3(g)à2HCo(PF3)4(l)
a. Co(s)
b. H2(g)
c. PF3(g)
d. HCo(PF3)4(l)
e. BothCo(s)andH2(g)
23. WhatisthestandardheatofcombustionofCH4(g)?Usethefollowingdata:
StandardHeatsofFormation
CH4(g)
-74.8kJ/mol
CO2(g)
-393.5kJ/mol
H2O(l)
-285.8kJ/mol
a.
b.
c.
d.
-890.3kJ/mol
-604.6kJ/mol
-252.9kJ/mol
-182.5kJ/mol
24. 10.0kJofheatareaddedtoonekilogramofironat10.°C.Whatisthefinaltemperatureoftheiron?The
specificheatofironis0.45J/g-°C.
a. 22˚C
b. 27˚C
c. 32˚C
d. 37˚C
25. Ozonecanbedestroyedthroughreactionwith
a. Anoxygenradical
b. UVradiation
c. Nitrogengas
d. Botha&b
26. Chlorofluorocarbonscontributetoozonedepletionby
a. Releasingchlorineradicals
b. Directlyreactingwithozone
c. Releasingfluorineradicals
d. Inhibitingtheabilityofozonetomigratetoareasoflowconcentration
27. Whichofthefollowingisnotacommoncontributingreactiontoozonedepletion?
a. HO+O3àHO2+O2
b. NO+O3àNO2+O2
c. ClO+OàCl+O2
d. PO3+Oà PO2+O2
28. CFCstandsfor
a. ChlorinatedFreoncompound
b. Chlorofluorocarbon
c. Carbonatedfluorinecompound
d. Causticfluorinecarbohydrate
e. Carbofluorocompound
29. Theconcentrationofwhichgreenhousegashasincreasedsteadilyoverthelawfewdecades?
a. H2O
b. CO
c. CO2
d. H2O2
e. O2
30. ClatomsformedviaphotolysisofC-ClbondsofCFC’sinthestratosphereareparticularlyeffectivein
destroyingozoneatthesealtitudesbecause
a. ClatomsabsorbUV,whichgenerateOatomstoreactwithO2toproduceozone
b. ClatomscatalyticallyconvertO3toO2
c. ClatomsstoichiometricallyconvertO3toO2
d. ClatomsreactwithHatoms,whichcatalyzeconversionofO2toO3
e. ClatomsreactwithNatoms,whichcatalyzeconversionofO2toO3
Completion–solvethefollowingproblems.Reportyouranswersonthescantronforminthespaceprovided.Besure
toincludeunitsandsignificantfigureswithyourfinalanswer.
31. A4.22gsampleofcopper(II)sulfidewasaddedtoexcesshydrochloricacid,andtheresultinghydrogen
sulfidegaswascollectedoverwater.Whatvolumeofgaswascollectedat30.5°Cwhentheatmospheric
pressurewas749torr?
32. Whatistheheatchangethattakesplacewhen36.0gofwateratatmosphericpressurecoolsfrom125°Cto
40.°C?
ScienceOlympiad–ChemistryLab
Part2-LabComponent
BackgroundInformation:Inthislabyouwillcombinetwosolutionsthatreactina1:1ratioinorderto
formaproduct.Thestoichiometryofthereactionisasfollows:
A+BàC
TaskDetails:Usecalorimetrytodeterminetheenthalpyofreactionoftheproduct,“C”,inkJ/mol.
Assumethatthecalorimeterisperfectlyinsulating,thatthespecificheatofthesolutionis4.184J/(g•°C),
andthatthedensityofthesolutionis1.00g/mL.Writeyourfinalanswerintheboxprovidedatthe
bottomofthispagewiththecorrectsign,significantfigures,andunits.
MaterialsList:
• Coffee-cupcalorimeter(maximumvolumeof_____mL)
• Thermometer
• SolutionA(___mLmax.)
• SolutionB(___mLmax.)
• GraduatedCylinder
• Distilledwater
Disposal:Allsolutionscanbedisposedofinthesinkwithcopiousamountsofwater.
Data:Clearlyrecordallmeasurementsbelow.
Calculations:Clearlyshowallcalculationsbelow.
FinalAnswer: