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1994 Three hoursareallotted forthis examination: 1hour and30minutes forSection I,which consists ofmultiple-choice questions, and1hour and30minutes forSection II,which consists ofproblems andessay questions. SectionIis printed in this examination booklet;SectionII,inaseparate booklet. Battery-operated hand-heldcalculators maybeused inboth sections ofthe examination. Allcalculator memoriesmust be cleared ofboth programs anddata; noperipheral devicessuchasmagnetic cardsortapes willbeallowed. Calculators may notbeshared. Time-1hour and30minutes Number ofquestions -75 Percent oftotal grade -45 This examination contains75multiple-choice questions.Therefore, pleasebecareful tofill inonly the ovals thatarepreceded bynumbers 1through 75on your answer sheet. INDICATE ALLYOUR ANSWERS TOQUESTIONS INSECfION IONTHESEPARATE ANSWERSHEET. No credit willbegiven foranything writteninthis examination booklet,butyou may usethebooklet fornotes or scratch work.Afteryouhave decided whichofthe suggested answersisbest, COMPLETELY fillinthe corresponding oval onthe answer sheet.Giveonlyoneanswer toeach question. Ifyou change ananswer, besure thattheprevious mark iserased completely. Chicago isa (A) state (B) city (C) country. (D) continent (E) village Many candidates wonderwhether ornot toguess theanswers toquestions aboutwhich theyarenotcertain. Inthis section ofthe examination, asacorrection forhaphazard guessing,one-fourth ofthe number ofquestions youanswer incorrectly willbesubtracted fromthenumber ofquestions youanswer correctly. Itis improbable, therefore,thatmere guessing willimprove yourscore significantly; itmay even lower yourscore, anditdoes taketime. If,however, youare not sure ofthe correct answer buthave some knowledge ofthe question andareable toeliminate oneormore ofthe answer choices aswrong, yourchance ofgetting theright answer isimproved, anditmay betoyour advantage toanswer such aquestion. . Use your timeeffectively, workingasrapidly asyou canwithout losingaccuracy. Donot spend toomuch timeon questions thataretoo difficult. Goontoother questions andcome backtothe difficult oneslaterifyou have time. Itis not expected thateveryone willbeable toanswer allthe multiple-choice questions.
I DO NOT DETACH FROMBOOK. I 1 2 H He 1.0079 4.0026 3 4 567 8 910 Li Be B C N 0 F Ne 6.941 9.012 10.81112.011 14.007 16.0019.0020.179 11 12 1314 1516 17 18 Na Mg AlSi P S CI Ar 22.99 24.30 26.9828.0930.974 32.0635.453 39.948 19 20 2122 232425 26 27 2829 30313233 34 35 36 K Ca ScTi V Cr Mn Fe Co NiCu Zn Ga GeAs SeBr Kr 39.10 40.0844.96 47.90 50.9452.0054.938 55.8558.9358.69 63.55 65.3969.72 72.59 74.9278.96 79.90 83.80 37 383940 41 4243 44 4546 47 4849 505152 53 54 Rb Sr Y Zr NbMo TcRu Rh Pd Ag Cd InSn Sb Te I Xe 85.47 87.6288.9191.22 92.91 95.94 (98)101.1 102.91 106.42 107.87112.41 114.82118.71121.75 127.60 126.91131.29 55 565772 7374 75 76 777879 80 8182 83 84 85 86 Cs Ba *La HfTa W Re Os IrPtAu Hg TIPb BiPo At Rn 132.91 137.33138.91178.49 180.95 183.85186.21 190.2 192.2.195.08 196.97200.59 204.38 207.2208.98 (209) (210)(222) 87 8889 104 105106 107 108 109 Fr RatAc Unq Unp Unh UnsUno Une (223) 226.02 227.03 (261)(262) (263)(262) (265) (266) 58 59 60 61 62 6364 6566 67 6869 70 71 Ce PrNd PmSm Eu Gd Tb Dy Ho ErTm Yb Lu 140.12 140.91 144.24 (145) 150.4151.97 157.25158.93 162.50 164.93167.26168.93 173.04 174.97 90 91 9293 94 959697 98 99100 101 102 103 Th Pa U Np Pu Am Cm Bk CfEs Fm Md NoLr 232.04 231.04 238.03237.05 (244) (243) (247)(247)(251) (252) (257)(258) (259) (260) ~ I" ~ ::l. e :; . ...• ~ (l) g: 0' ~ :;' (JQ ...• ~ Ci' :3 ~ ~ .... 0' 8 (l) I ~ en •.....• n (l) ::r C/.l ~ 0 tTl ~ •.....• ~ n .... ~ 8- ::j I" ~ ~~ en ~ W ..... ~ (l) 0 ::l. g. ~ (JQ ...• g ::r (l) (l) ..c en ~ (l) en 0. 0 ~ en ...•. ~ §: en en (l) n f=t. 0 ~ 0 •..•.. ...• ::r (l) (l) >< ~. ~ I" 0. 0 p
Note:Forallquestions involving solutionsand/orchemical equations, assumethatthesystem isin pure water andat room temperature unlessotherwise stated. . Directions: Eachsetoflettered choices belowreferstothe numbered questionsorstatements immediately following it. Select theone lettered choicethatbest answers eachquestion orbest fitseach statement andthen fillinthe corresponding ovalonthe answer sheet.Achoice maybeused once, morethanonce, ornot atall ineach set. Questions 5-7refer tothe phase diagram belowofa pure substance. (A) Heisenberg uncertainty principle (B) Pauli exclusion principle (C) Hund's rule(principle ofmaximum multiplicity) (D) Shielding effect (E) Wave nature ofmatter 1. Can beused topredict thatagaseous carbonatom in its ground stateisparamagnetic P (atIp) 1.0 1030 50 7090110 130 TeC) 2. Explains theexperimental phenomenonofelectron diffraction 3. Indicates thatanatomic orbitalcanhold nomore than twoelectrons (A) Sublimation (B) Condensation (C) Solvation (D) Fusion (E) Freezing 4. Predicts thatitis impossible todetermine simulta- neously theexact position andtheexact velocity of an electron 5.Ifthe temperature increasesfrom10°Cto 60° Cat a constant pressure of0.4 atmosphere, whichofthe processes occurs? 6. Ifthe temperature decreasesfrom110°Cto 40° Cat a constant pressure of1.1 atmospheres, whichof the processes occurs? 7. Ifthe pressure mcreases from0.5to1.5 atmospheres at aconstant temperature of50° C,which ofthe processes occurs? GOONTOTHE NEXT PAGE
(A)Li2 (B) B 2 (C) N 2 (D) O 2 (E) F 2 (A) Pb (B) Ca (C) Zn (D) As (E) Na 12. Isadded tosilicon toenhance itsproperties asa semiconductor GOONTOTHE NEXT PAGE
Directions:Eachofthe questions orincomplete statementsbelowisfollowed byfive suggested answersorcompletions. Select theone that isbest ineach caseandthen fillinthe corresponding ovalonthe answer sheet. 14. Which ofthe following islower foral.O-molar aqueous solutionofany solute thanitis for pure water? (A) pH (B) Vapor pressure (C) Freezing point (D) Electrical conductivity (E) Absorption ofvisible light 15. Inamolecule inwhich thecentral atomexhibits sp 3 d 2 hybrid orbitals, theelectron pairsaredirected toward thecorners of (A) atetrahedron (B) asquare-based pyramid (C) atrigonal bipyramid (D) asquare (E) anoctahedron 16. Commercial vinegarwastitrated withNaOH solution todetermine thecontent ofacetic acid, HC2H3 0 2 •For 20.0 milliliters ofthe vinegar, 26.7 milliliters of0.600-molar NaOHsolution was required. Whatwastheconcentration ofacetic acid inthe vinegar ifno other acidwaspresent? (A) l.60 M (B) 0.800 M (C) 0.600 M (D) 0.450 M (E) 0.200 M 17. Relatively slowrates ofchemical reactionareasso- ciated withwhich ofthe following? (A) Thepresence ofacatalyst (B) High temperature (C) High concentration ofreactants (D) Strong bondsinreactant molecules (E) Low activation energy GO ONTOTHE NEXT PAGE
Whichspecies actsasan oxidizing agentinthe reaction represented above? (A) H 2 0 (B) Cl0 4- (C) CI0 2- (D) Mn02 (E) Mn04- 19. Inwhich ofthe following compounds isthe mass ratioofchromium to oxygen closestto1.62 toLOa? (A) cr0 3 (B) cr0 2 (C) crO (D) Cr20 (E) C r 2 0 3 When theequation aboveisbalanced withlowest whole-number coefficients,the coefficient forOH- is (A) 2 (B) 4 (C) 5 (D) 6 (E) 7 GOONTOTHE NEXT PAGE
21.Correct statements aboutalphaparticles include which ofthe following? I. They haveamass number of4and acharge of +2. II. They aremore penetrating thanbetaparticles. ill. They arehelium nuclei. (A) Ionly (B) ill only (C) Iand II (D) Iand ill (E) IIand ill In the equilibrium representedabove,thespecies that actasbases include whichofthe following? I. HS0 4- II. H 2 0 ill. SO/- (A) IIonly (B) ill only (C) Iand II (D) Iand III (E) IIand ill The proposed stepsforacatalyzed reaction between Ce4'"andTl'"arerepresented above.The products ofthe overall catalyzed reactionare (A) Ce 4'" andTI'" (B) Ce 3.•. and TP'" (C) Ce 3.•. and Mn 3.•. (D) Ce3.•.and Mn4.•. (E) TP'"andMn z", 24. Asample of0.0100 moleofoxygen gasisconfined at 37° Cand 0.216 atmosphere. Whatwould bethe pressure ofthis sample at15° Cand thesame volume? (A) 0.0876 atm (B) 0.175 atm (C) 0.201 atm (D) 0.233 atm (E) 0.533 atDl GOONTOTHE NEXT PAGE
1 Hlg) + '2 02(g) ~ H 2 0(2) 1 2 Na(s) + '2 02(g) ~Na20(s) 1 1 Na(s) + '2 02(g) + '2 H2(g) ~NaOH(s) Based onthe information above,whatisthe standard enthalpy change forthe following reaction? (A) -1,125 kJ (B) -978kJ (C) -722kJ (D) -150kJ (E) +275kJ 26. Which ofthe following actionswouldbelikely to change theboiling pointofasample ofapure liquid inan open container? 1. Placing itin asmaller container II. Increasing thenumber ofmoles ofthe liquid in the container . ill. Moving the'container andliquid toahigher altitude (A) Ionly (B) IIonly (C) ill only (D) IIand ill only (E) I,II, and ill 27. Which ofthe following setsofquantum numbers (n, t,m2, m.d best describes thevalence electron of highest energyinaground-state galliumatom (atomic number31)? 1 (A) 4,0,0, '2 1 (B) 4,0, 1, '2 1 (C) 4,I,1, '2 1 (D) 4,1,2, '2 1 (E) 4,2,0, '2 GOONTOTHE NEXT PAGE
28.Given thatasolution is5percent sucrosebymass, what additional information isnecessary tocalculate the molarity ofthe solution? I. The density ofwater IT. The density ofthe solution ill. Themolar massofsucrose (A) Ionly (B) IT only (C) illonly (D) Iand ill (E) IT and ill 29. When anaqueous solutionofNaOH isadded to an aqueous solutionofpotassium dichromate, K2Cr207. thedichromate ionisconverted to (A) crO/- (B) cr0 2- (C) Cr3 + (D) Cr203(S) (E) Cr(OHMs) 30. The energy diagram forthe reaction X+Y ~ Zis shown above.Theaddition ofacatalyst tothis reac- tion would causeachange inwhich ofthe indi- cated energy differences? (A) Ionly (B) IT only (C) illonly (D) Iand IT only (E) LIT, andill GOONTOTHE NEXT PAGE
31.H 2 C 2 0 4 +2H 2 0 P 2H 3 0+ + C 2 0l- Oxalic acid,H2C204, isadiprotic acidwith K 1 = 5.36 X 10- 2 and K 2 = 5.3 x10- 5• Forthe reaction above,whatisthe equilibrium constant? (A) 5.36 x10-2 (B) 5.3x10- 5 (C) 2.8 x 1O~ (D) 1.9X10-10 (E) 1.9 x 10-13 32. CH 3 CH 2 0H boilsat78° Cand CH 3 0CH 3 boilsat -24° C,although bothcompounds havethesame composition. Thisdifference inboiling pointsmay be attributed toadifference in (A) molecular mass (B) density (C) specific heat (D) hydrogen bonding (E) heat ofcombustion 33. Ahydrocarbon gaswith anempirical formulaCH2 has adensity of1.88 grams perliter at0° Cand 1.00 atmosphere. Apossible formulaforthe hydro- carbon is (A) CH2 (B) C2~ (C) C 3 H 6 (D) C 4 H g (E) C 5 H IO Based onconcepts ofpolarity andhydrogen bonding,whichofthe following sequences correctly liststhecompounds aboveinthe order oftheir increasing solubilityinwater? (A) Z < Y < X (B) Y < Z < X (C) Y < X < Z (D) X < Z < Y (E) X < Y < Z GO ,ON TOTHE NEXT PAGE
35.Forwhich ofthe following processes wouldM have anegative value? 1. 2Fe 1 03(s) ~ 4 Fe(s) + 3 OI(g) II. Mg 1• +2OH- ~Mg(OHMs) ill. H 2(g) + C2~(g) ~ Cl~(g) (A) I only (B) I and II only (C) I and ill only (D) II and ill only (E) I,II, and ill An electrolytic cellbased onthe reaction repre- sented abovewasconstructed fromzincandcopper half-cells. Theobserved voltagewasfound tobe 1.00 voltinstead ofthe standard cellpotential, EO, of 1.10volts. Which ofthe following couldcorrectly account forthis observation? (A) The copper electrode waslarger thanthezinc electrode. (B) The Zn l• electrolyte wasZn(N0 3 h, whilethe Cu2• electrolyte wasCUS04. (C) The Zn2• solution wasmore concentrated than the CUI. solution. (D) The solutions inthe half-cells haddifferent volumes. (E) The saltbridge contained KClasthe elec- trolyte. 37. Asample of3.30 grams ofan ideal gasat150.0°C and 1.25 atmospheres pressurehasavolume of 2.00 liters. Whatisthe molar mass of the gas? The gasconstant, R,is0.0821 (L·atm)/(mol •K). (A) 0.0218 gram/mole (B) 16.2 grams/mole (C) 37.0 grams/mole (D) 45.8 grams/mole (E) 71.6 grams/mole 38. Concentrations ofcolored substances arecommonly measured bymeans ofaspectrophotometer. Which of the following wouldensure thatcorrect values are obtained forthe measured absorbance? 1. There mustbeenough sampleinthe tube to cover theentire lightpath. II. The instrument mustbeperiodically reset using astandard. ill. Thesolution mustbesaturated. (A) I only (B) II only (C) I and II only (D) II and illonly (E) I,II, and ill 39. Samples ofF 2 gas and Xegas aremixed ina container offixed volume. Theinitial partial pres- sure ofthe F 1 gas is8.0 atmospheres andthat of the Xegas is1.7 atmospheres. Whenallofthe Xe gas reacted, forrning asolid compound, thepres- sure ofthe unreacted F 1 gas was 4.6atmospheres. The temperature remainedconstant.Whatisthe formula ofthe compound? (A) XeF (B) XeF 3 (C) XeF4 (D) XeF6 (E) XeFs GOONTOTHE NEXT PAGE
-T- _h j =.:!61 mm Hg(Q) / Closed-end Manometer The system shownaboveisat equilibrium at28° C. At this temperature, thevapor pressure ofwater is 28 millimeters ofmercury. Thepartial pressure of 02( g)inthe system is (A) 28 mm Hg (B) 56 mm Hg (C) 133 mm Hg (D) 161mm Hg (E) 189 mm Hg A strip ofmetallic scandium, Sc,isplaced ina beaker containing concentrated nitricacid.A brown gasrapidly forms,thescandium disappears, and theresulting liquidisbrown-yellow but becomes colorlesswhenwarmed. Theseobserva- tions bestsupport whichofthe following state- ments? (A) Nitric acidisastrong acid. (B) Insolution scandium nitrateisyellow and scandium chlorideiscolorless. (C) Nitric acidreacts withmetals toform hydrogen. (D) Scandium reactswithnitric acidtoform a brown gas. (E) Scandium andnitric acidreact inmole propor- tions of1to 3. Mass ofan empty container Mass ofthe container plus the solid sample Volume ofthe solid sample 25.0 grams 11.0 cubic centimeters The data above weregathered inorder todetermine the density ofan unknown solid.Thedensity ofthe sample shouldbereported as (A) 0.5g/cm 3 (B) 0.50 g/cm3 (C) 2.0g/cm3 (D) 2.00 g/cm 3 (E) 2.27 g/cm 3 43. Which ofthe following pairsofcompounds are isomers? 44. Which ofthe following solutionshasthelowest freezing point? (A) 0.20 mCJI12 06, glucose (B) 0.20 mNILBr (C) 0.20 mZnS04 (D) 0.20 m KMn04 (E) 0.20 mMgCh .GO ONTOTHE NEXT PAGE
45.Asample ofan ideal gasiscooled from50.0° Cto 25.0° Cin asealed container ofconstant volume. Which ofthe following valuesforthe gas will decrease? 1. The average molecular massofthe gas II. The average distance between themolecules III. Theaverage speedofthe molecules (A) Ionly (B) IIonly (C) III only (D) I and III (E) II and III 46. Which ofthe following solidsdissolves inwater to form acolorless solution? (A) CrCb (B) FeCh (C) CoCl l (D) CuCh (E) ZnCh 47. Which ofthe following hasthelowest conductivity? (A) 0.1 M CUS04 (B) 0.1 M KOH (C) 0.1 M BaCh (D) 0.1 M HF (E) 0.1 M HN03 Some PCbandCharemixed inacontainer at 200° Cand thesystem reaches equilibrium according tothe equation above.Which ofthe following causesanincrease inthe number of moles ofPCls present atequilibrium? 1. Decreasing thevolume ofthe container II. Raising thetemperature III. Adding amole ofHe gas atconstant volume (A) Ionly (B) IIonly (C) I and III only (D) II and III only (E) I,II, and III 49. The isomerization ofcyclopropane topropylene is a first~order processwithahalf-life of19minutes at 500° C.The time ittakes forthe partial pressure of cyclopropane todecrease from1.0atmosphere to 0.125 atmosphere at500· Cisclosest to (A) 38minutes (B) 57minutes (C) 76minutes (D) 152minutes (E) 190minutes 50. Which ofthe following acidscanbeoxidized to form astronger acid? (A) H 3 P0 4 (B) HN03 (C) H2C0 3 (D) H 3 B0 3 (E) H 2 S0 3 Equal numbers ofmoles ofHCl andO2inaclosed system areallowed toreach equilibrium asrepre- sented bythe equation above.Which ofthe following mustbetrue atequilibrium? I. [HCl] mustbeless than [CI 2]. II. [02] must begreater than[HCl]. III. [Ch] must equal [H20]. (A) Ionly (B) IIonly (C) I and III only (D) II and III only (E) I,II, and III GOONTOTHE NEXT PAGE
52.When dilutenitricacidwasadded toasolution of one ofthe following chemicals, agas was evolved. This gasturned adrop oflimewater, Ca(OHh, cloudy, duetothe formation ofawhite precipitate. The chemical was (A) household ammonia,NH 3 (B) baking soda,NaHC03 (C) table salt,NaCI (D) epsom salts,MgS0 4 • 7H20 (E) bieach, 5%NaOCl If 87 grams ofK2S04 (molar mass174grams) is dissolved inenough watertomake 250milliliters of solution, whatarethe concentrations ofthe potas- sium andthesulfate ions? [K+] (A) 0.020 M (B) l.OM (C) 2.0 M (D) 2.0 M (E) 4.0 M [SO/-] 0.020 M 2.0M l.0 M 2.0M 2.0M 54. Allofthe following statements concerning the characteristics ofthe halogens aretrue EXCEPT: (A) The first ionization energies(potentials) decrease asthe atomic numbers ofthe halo- gens increase. (B) Fluorine isthe best oxidizing agent. (C) Fluorine atomshavethesmallest radii. (D) Iodine liberates freebromine fromasolution of bromide ion. (E) Fluorine isthe most electronegative ofthe halogens. 55. What volume of0.150-molar HCIisrequired to neutralize 25.0milliliters of0.120-molar Ba(OH)2? (A) 20.0 mL (B) 30.0 mL (C) 40.0 mL (D) 60.0 mL (E) 80.0 mL 56. Itis suggested thatS02 (molar mass64grams), which contributes toacid rain, could beremoved from astream ofwaste gasesbybubbling thegases through 0.25-molar KOH,thereby producing K2S0 3• What isthe maximum massofS02 thatcould be removed by1,000. litersofthe KOH solution? (A) 4.0kg (B) 8.0kg (C) 16kg· (D) 20.kg (E) 40.kg 57. Molecules thathave planar configurations include which ofthe following? 1. BCh II. CHCh ill. NCh (A) Ionly (B) ill only (C) Iand IIonly (D) IIand ill only (E) I,II, and ill The reaction indicated aboveisthermodynamically spontaneous at298 K,but becomes nonspontaneous at higher temperatures. Whichofthe following is true at298 K? (A) ,6.G, t:::Jf, and,6.8areallpositive. (B) ,6.G, t:::Jf, and,6.8areallnegative. (C) ,6.G and t:::Jf arenegative, but 68 ispositive. (D) ,6.G and M arenegative, but t:::Jf ispositive. (E) ,6.Gand t:::Jf arepositive, butMisnegative. GO ONTOTHE NEXT PAGE-
59.When a1.00-gram sampleoflimestone was dissolved inacid, 0.38gram ofCO2 wasgenerated. If the rock contained nocarbonate otherthan CaC03, whatwasthepercent ofCaC03 bymass in the limestone? (A) 17% (B) 51% (C) 64% (D) 86% (E) 100% According tothe data inthe table below, whatis the value off::Jl0 forthe reaction represented above? AverageBondEnergy Bond (kilojoules/mole) I-I CI-CI I-CI (A) -860kJ (B) -382kJ (C) +180kJ (D) +450kJ (E) +1,248 kJ 149 239 208 61. AI-molar solution ofwhich ofthe following salts has thehighest pH? (A) NaN03 (B) Na 2 C0 3 (C) NaCI (D) NaHS04 (E) Na2S04 62. The electron-dot structure(Lewisstructure) for which ofthe following molecules wouldhavetwo unshared pairsofelectrons onthe central atom? (A) H 2 S (B) NH 3 (C) C~ (D) HCN (E) CO 2 63. What isthe maximum massofcopper thatcould be plated outbyelectrolyzing aqueousCuCl2for 16.0 hours ataconstant currentof3.00 amperes? (l faraday = 96,500 coulombs) (A) 28grams (B) 57grams (C) 64grams (D) 114grams (E) 128grams 64. At25° C,asample ofNH3 (molar mass17grams) effuses atthe rate of0.050 moleperminute. Under the same conditions, whichofthe following gases effuses atapproximately one-halfthatrate? (A) O2(molar mass32grams) (B) He(molar mass4.0grams) (C) CO2 (molar mass44grams) (D) Cb(molar mass71grams) (E) C~ (molar mass16grams) 65. Barium sulfateisLEAST solubleinaO.Ol-molar solution ofwhich ofthe following? (A) Ah(S04)3 (B) (~)2S04 (C) Na2S04 (D) NH 3 (E) BaCh 66. What isthe pH ofa1.0 x1O-2-molar solutionof HCN ?(Fot HCN, K a = 4.0 x10- 10.) (A) 10 (B) Between 7and 10 (C) 7 (D) Between 4and 7 (E) 4 ~ GO ONTOTHE -NEXT PAGE
67.Substances Xand Ythat were inasolution were separated inthe laboratory usingthetechnique of fractional crystallization. Thisfractional crystalliza- tion ispossible becausesubstances Xand Yhave different (A) boiling points (B) melting points (C) densities (D) crystal colors (E) solubilities 68. Which ofthe following molecules hasadipole moment ofzero? (A) C6H6 (benzene) (B) NO (C) S02 (D) NH 3 (E) H2S 69. Correct procedures foratitration includewhichof the following? 1. Draining apipet bytouching thetiptothe side of the container usedforthe titration II. Rinsing theburet withdistilled waterjustbefore filling itwith theliquid tobe titrated III. Swirling thesolution frequently duringthetitra- tion (A) Ionly (B) IIonly (C) Iand IIIonly (D) IIand IIIonly (E) I,II, and III 70. Todetermine themolar massofasolid mono- protic acid,astudent titrated aweighed sampleof the acid with standardized aqueousNaOH.Which of the following couldexplain whythestudent obtained amolar massthatwastoolarge? . I. Failure torinse allacid from theweighing paper into thetitration vessel II. Addition ofmore water thanwasneeded to dissolve theacid III. Addition ofsome basebeyond theequivalence point (A) Ionly (B) IIIonly (C) Iand IIonly (D) IIand IIIonly (E) I,II, and III If 1mole ofO2 oxidizes Fe(0H)2 according tothe reaction represented above,howmany moles of Fe(0H)3 canbeformed? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6
72.The nuclide 2::Cmisradioactive anddecays bythe loss ofone beta (~-)particle. Theproduct nuclideis (A) 2:~PU (B) 245 A 95 m (C) 248C 96 m (D) ~~Cm (E) 249Bk 97 When 0.40mole ofS02 and0.60 mole ofO2 are placed inan evacuated 1.00-literflask,thereaction represented aboveoccurs. Afterthereactants and theproduct reachequilibrium andtheinitial temperature isrestored, theflask isfound tocontain 0.30 mole ofS03. Based onthese results, theequi- librium constant, K c,forthe reaction is (A) 20. (B) 10. (C) 6.7 (D) 2.0 (E) 1.2 74. Asolution ofcalcium hypochlorite, acommon additive toswimming-pool water,is (A) basic because ofthe hydrolysis ofthe OCI- ion (B) basic because Ca(01-n2 isaweak andinsoluble base (C) neutral ifthe concentration iskept below 0.1 molar (D) acidic because ofthe hydrolysis ofthe Ca2 + ions (E) acidic because theacid HOCI isformed 75. Adirect-current powersupply oflow voltage (less than 10volts) haslostthemarkings thatindicate which output terminal ispositive andwhich is negative. Achemist suggests thatthepower supply terminals beconnected toapair ofplatinum elec- trodes thatdipinto O.l-molar KIsolution. Which of the following correctlyidentifies thepolarities of the power supply terminals? (A) Agas will beevolved onlyatthe positive elec- trode. (B) Agas will beevolved onlyatthe negative elec- trode. (C) Abrown colorwillappear inthe solution near the negative electrode. (D) Ametal willbedeposited onthe positive elec- trode. (E) None ofthe methods abovewillidentify the polarities ofthe power supply terminals. IF YOU FINISH BEFORE TIMEISCALLED, YOUMAY CHECK YOURWORK ONTHIS SECTION. DO NOT GOONTOSECTION IT UNTIL YOUARETOLD TODO SO.
ChapterIII. Answers tothe 1994 APChemistry Examination Listed belowarethe correct answers tothe multiple- choice questions andthepercentage ofAP candidates who attempted eachquestion andanswered itcor- rectly. Asageneral rule,candidates whocorrectly answered anindividual questioninthis section also achieved ahigher meanscoreonthe test asawhole than candidates whodidnot answer thatquestion correctly. Ananswer sheetgridded withthecorrect responses appearsonthe next page. Section IAnswer KeyandPercent Answering Correctly Item Correct Percent ItemCorrect Percent Item Correct Percent No. Answer Correct No.Answer Correct No.Answer Correct 1 C 26 C 51 D 2 E 27 C 52 B 3 B 28 E 53 E 4 A 29 A 54 D 5 A 30 D 55 C 6 B 31 C 56 B 7 B 32 D 57 A 8 C 33 C 58 B 9 D 34 E 59 D 10 C 35 D 60 B 11 C 36 C 61 B 12 D 37 D 62 A 13 A 38 C 63 B 14 C 39 C 64 D 15 E 40 C 65 A 16 B 41 D 66 D 17 D 42 D 67 E 18 E 43 A 68 A 19 B 44 E 69 C 20 D 45 C 70 A 21 D 46 E 71 C 22 E 47 D 72 E 23 B 48 A 73 A 24 C 49 B 74 A 25 D 50 E 75 B