ACT Past Papers with Answers

Paper 70 · ACT June 2007 · Form 65C · Science Test

In Study 2, as Ihe lentrth of the conductinp rod increased, the amount of electrical current throuoh the loop: incr￿aSed only. rernained constant. ,￿led, bui w'iEh llo general trend.

Paper 70 · ACT June 2007 · Form 65C · Science Test

In Study 3, 1 M'ould most likely hai.'e equaled +5.6 rnA if B had equaled ￿'bIch of the followino? -4. 0.50 T Trial | p (m/scc} l (MA} Siudy 2 The students moiTed rods of various L to Lhe right at

Paper 70 · ACT June 2007 · Form 65C · Science Test

During each trial, all electrical current flowed throuoh Ihe circuit because the motion-of the conducting rod in tbe maonetic field produced a nonzero iroltage in tbc circuil. Assurnino that the electrical resistance in th.e circuit was ihe same across Trials 2, 7, 8, and 9, durinu which of Ihese ￿1￿15 W &S the voliage greaiesl? Trial 9 Trial L(m) l (nL4) Study S The students moved a rod of L - O.?0 m io the rigELt al

Paper 70 · ACT June 2007 · Form 65C · Science Test

In ￿hICh of the siudies, if any, did the electrical cui- ienl tnoi:e counterclockwise? C, Studies 1, 2, and 3 only

Paper 70 · ACT June 2007 · Form 65C · Science Test

The resulis of Study 4 are best represented by w'hich of the followino graphs . Table 3 Trial B(T) l (raA)

Paper 70 · ACT June 2007 · Form 65C · Science Test

Tible l is used to identify animals that belong io whith of the followkng £ioups? Table 2 Anurall Traits 8 in length larue parolid glands blO￿,n back hitc throat and chest viith black markings unpadded ioes verticall} al joned pupils 9 cm in length DO 12rge paroiid tplands eyes look ouiward skin folds on back unpadded toes i ertically aligned pupils 4 cm in length broNN n back with black spots eye5 look outward no I￿ge parotid glands horizontally aligned pupils 3 cm in length black c)e stripe present unpadded ioes 'ertic&lly aligned pupils • DO larttè p￿01]d glands no 5Lin folds on back '

Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on the iiformation proNided, th¢ anuran listed in Table l ihat is rrLOSt closely related to Bufo boreas most likely has which of Ibe followinLT characieristics? A light stripc across its snout

Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on Table I, ffi'hich of the following traits of Anuran X indicates it is liOT a Hyla regilla

Paper 70 · ACT June 2007 · Form 65C · Science Test

The results from Table I for Anuran Y and Anuran Z fllst diverue al IN'hich of the follo￿.1￿g steps. 11, .4ccording to T&ble .], Rana cascadae and Rana Inu5C05a botb hai'e ￿h1¢h of tbc following trails? .C. Red groin color iables 1 and 2 aoapted from U.S. Departrngnt of Agriculture and Forest SeNice, R-5 Fish Habitat Flelationship Technical Bulletin, Num>Ér 4, Monitoring Frogs and Toads in Region 5 National Fores,'s. 1091. 41 GO ON TO THE NEXT PAGE. ACT4SC Passage 111

Paper 70 · ACT June 2007 · Form 65C · Science Test

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Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on Figure 2, at 250 sec, tile thermomeler ieadin in the 40°C air most likely was closest io which of the follo￿.￿ng. A ￿erCUrY thermometer, at an initial ternperature of 20°C, w as placed in 30°C water, and the temperature regis- tcred by the thermometer was recorded over time. This pro- cedure ￿.aS repealed using ll'ater samples ai 40°C and 50°C (see Figure l). Next, the same thermometer, at an initial iemperaturc of 50'C, w'as placed in an air sarnple at 20°C, and Ihe temperature retristered by the thernlometer was recorded over time. This procedure w'as Tepeated usincr air samples ai 30°C and 40°C (see FigJi re 2). (Noie: Assuroe that the designated temperatures of Ehe waLer Samples and air samples did not change durino the measurements.)

Paper 70 · ACT June 2007 · Form 65C · Science Test

ThThen the thermorneter was in the 50°C ￿'ale[, in Ih: (l￿e interiral between 2 sec and 3 sec, 2pproximateli' how, Tapidli., in 'Clsec. w'as the temperature reviSLered - by the thermorneter cbangino? l°Cfsec 4°Clsec Ke) water tcmperature= 50'C 40°C 30'C

Paper 70 · ACT June 2007 · Form 65C · Science Test

Accordinu to Fiuure 2, for an air tempeiature .of 20'C: over wbich of the folloTh"ing tirne inter￿al$ Th as the Ihermometer readinc chanryino most rapidlv? O-11)0 sec 0 1_0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 Lime (sec) Fioure I Key air temperature". 40°C io'c 20°C

Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on Figur¢ 2, for the thermometer placed in 30'C air. the averètse kinetic energy of the mercury atonig in the thermometer Iwas greatest ai ￿'hICh of the folloThillo tines?

Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on Ficrure 2, if the thermometer, ai all inipial iemper&ture of 50°C, had been placed in an air saEnp!e at IO°C, how long would it most likely have taken Ib.e Ihermomeler reading to r.each IO'C ? O LOO 200 300 400 500 600 7CM) 800 time (sec) Figuie 2 Figbres 1 and 2 adap'ied from Volkèr Thomsen."Response fime of Therrnometer." Q1998 by American Association of Physics Teachers. 42 GO ON TO THE NEXT PAGE. 4000000000 Passage IV Am)lase is an enzyn]e thai speeds up the breakdow'n of starch into smal.ler ¢arbohyd¥ates (such as maltose). A starch solution, an alnylase soluiLOtL. and several buffer soZuliorAS (solutions thal maintain a constanl pH) 'ere prepaied. Tw'o eXperI￿ents uiere done using Ehese soluiions and the following tests: Iodine test: 3 drops of a broll'n Kl soluiion is added to a sample soluuon.. If starch is presenE in the sample solu- tion. the solution ￿111 turn from brown to black. Benedict's test" I ML of a blue solution coniaininc CUSO is. added io a sarnple solution. Tbe solution is then heated in a boiling water b31h for 3 rnin. If maltose is present in the san]ple solulion, the soluiion w'ill turn fron blue to orange.

Paper 70 · ACT June 2007 · Form 65C · Science Test

Based on ihe passaoe, amvlase in humans IS rnDst directly associaLed wiib whicb ' of the following Systems.

Paper 70 · ACT June 2007 · Form 65C · Science Test

Suppose an additjonal trial had been done in Experi- ment 2 usinu a buffer soluiion wiiih a pH of 7.3. Whai 'ould be the most likely results of the iodine and Benedict's tests. Iodine test brown brow'n BenedicL'S tc.st blue orange blue orange black Experiment I Each of 7 test tubes was filled with 5 ML of pH 7.0 buffer soluiion. DiffeTeni amounis of starch solution andlor am)'lase solution were added to each tube. The soluliotl in each tube was then dilutcd to 10 rnL ￿'l(h the buffer solu- tion (so the final pH wras 7.0 in each lube). Each tube vias then incubated at a constant itsmperaiurc for 10 rnin. The iodine and Benedict's tests were then each done wilh 2 tnL samples drawn from each lube (see Table l).

Paper 70 · ACT June 2007 · Form 65C · Science Test

Ikith Thhich of the followring siaEernents aboui 501utes ould both siudents agree? Adding io 2 liquid a sub- stance that dissolves: and dis50ciates into ions will decrease the liquid's vapor pressure. and dissociates into ions will incréase ihe liquid's vapor pressure. liquid's vapor pressure. liquid's vapor pressLire. . 40. Assume Ihe following for ihe 2ddilion of 2 substance 10 a pure liquid: P = the decrease in vapor pressure Ihe concentration of solute pariicles a constant

Paper 70 · ACT June 2007 · Form 65C · Science Test

.4¢coidin£ to the results of the iodine and Benedicl, iesls, which of Tubes 1-4 in Experiment I contained both starch and maliose? . H. Tubes 2 and 4 onlv ('c) 30 35 40 45 50 50 50 Tube black black broy'n black black black brou'n blue orantye oranoe oranefe blue blue blue ?1. All of the experitneTrtal factors uiere ideniical fo- which of the followino tubes? Exp8fiTnent 2 SeNren test lubes were filled and tested accordino to the procedure used for Tube 3, excepi thal foi each tube, & differeni buffer solution was used (see Table 2).". Table 2 Iodine test Benedici's lest

Paper 70 · ACT June 2007 · Form 65C · Science Test

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Paper 70 · ACT June 2007 · Form 65C · Science Test

11.hich of the following best describes the relationship be[￿"eell ihe starcli concentration and the maltose con- centiation during the incubation of Tube 3 ? As ine starch concentratioll: constant incieased, the maltose concentration decreased. increased. iTrke m21tosc concentr21ion remakli ed constanl. Tube pH black black blue 10 11 blue orancye orancye" orange blue brown bro￿..n black black 14 43 GO ON TO THE NEXT PAGE. 40000000004 Passage V Siudents studied the pliotodecornposifion (breakdown by liuht) of p-nitrophenol (a ioxic pollulallt) in ¥[aSte￿,atcr. They measured the concenuaiion of p-ll1￿0pheno1 (in parts per million, ppm) in wastewater samples durillo exposure 10 N'arious lighiing conditions. Titanium dioxide (Ti02) andlor hldrogen peroxide (H O ) were added to sone san- 'ples ai Ihe start of exposure (time = O min). Tio and H O speed up some pkio1ode￿OMpOs1cIoll reactions. The results of 3 se15 of experirnents are shown in uies 1-3. H202 + sunligi]t sunlight sunlight 20 40 60 80 sutdight, no Tio TIO , no'.ljcvhi N ole.. All 3 samples w'ere exposed to the saEne inten51ry of sunlight. FiEure 3 no ligliE, ncT> io-" Figures adopted t,.om J. A, Herrera-melian el al., 'Soler Photo- ca:alvlic Destruction of pNitrDphenol: A Pedagogical use.ot La Was',es. Q2001 by Division of Chemical Education, Inc., American Cherni¢al Society. TI02 +.sun1￿l.-.---.. . 30 60 90 time (min) Note: For the 2 samples exposed to f unlight, the intensity of the sunlight ￿laS the same. 120 150 180 Figure I

Paper 70 · ACT June 2007 · Form 65C · Science Test

According to Figure 1, 60 min after Tio was added 10 the w&stewater sample chat was NOT exposed IQ SUV.- light, Lhe concentraiion of p-nitrophenol was closegL to hicb of the following.

Paper 70 · ACT June 2007 · Form 65C · Science Test

According to Figure I, for the sample that contained Tio and was exposed Eo sunLiuht, Lbe greatest amo" of p-nitrophenol decomposed during which of ihe f ol- lowing lime intervals? sunliohi, cloudy day sunli trht, sunny day Tio I&￿P 30 60 90 time (min) I20 150 180 Figure 2 44 GO ON TO THE NEXT PAGE. Acr4sc 0000000004

Paper 70 · ACT June 2007 · Form 65C · Science Test

For ￿,hICh of the 3 figures did all of the ￿,aSte￿'a1er samples studied have tbe same initial p-nitrophenol concentration.

Paper 70 · ACT June 2007 · Form 65C · Science Test

B ased on the information in the passaoe, Th'hich of ihe folloK¥'ing best describes and explains the resulLS shown in Figure 2 ? As timc increased from O min to 180 min, the concentration of p-niirophenol in the 3 samples: froLn a liquid to 2 gas. broke down to form other substances. increased, because the p-nitrophenol chantred from a liquid to a gas. increased, because the p-niirophenol molecule5 broke down to fortn oiher subscances.

Paper 70 · ACT June 2007 · Form 65C · Science Test

A Chellli￿ claitrked that adding. H O to wastcw'ater containing p-nicrophenol wilL cause the .p-nitrophenol .to deconpose in the absence of light. Do the resulis from any of the figure5 confirm her claim? centraiion otLl>' decreased in the satnple containino H O tested in the absence.of IiLTht. centration only decreased in the san]ple containip.o centralion only decreased in the saTtLple containin H O tested in the absence of light. in2 H O were tested in the absei& ce. of liglii. 45. GO ON TO THE NEXT PAGE. ACT45C 40000000004 Passage Vl llater flowing over the sedimeni in a rii'er channel Creates bedforms (3-dimensional structures formed in ibe sedimenc). The processes that produce bedforms in present- da>. riN'er channels produced thé sarDe t)'pes ol bedforms in ancient rii'er channels. Ancient bedforrns are often found preserN-ed in sediraentary rock .layers. Ficpure I shoM:s a longitL,dinak cross seciion of 3 ijpes of bedfor&￿s. ripples, dunes, and flat beds. Srud): J The bottom of the channel was covered with fine sand particles, all having a diameier of 0..19 mm. Water ￿'aS passed oi'er the sedinient bed. The r-sultincr bedform sza. biliry.. fields (u'attr velocities and water flow depths at which i'arious t}'pes of bedforms w'ere present) are shO￿.n in Fioure ? Kej ripples dunes eTosion of sedÉment, no bedfollns direction of water flow ripples Locm [IOcm > 0.1

Paper 70 · ACT June 2007 · Form 65C · Science Test

Nl,"hich of the.folloTh ino faciors was Ni OT directly con- "trollcd by the geologist durinc th¢ studies?

Paper 70 · ACT June 2007 · Form 65C · Science Test

Suppose Siudy I w ere r¢peated' using sand particles all having a di&rneter of 0.30 MLTL. The rcsulting bedforrn siability fields would include which of Ihe 3 tjpes of bedforrns referred Eo in thc passaue? -4. Ripples onlv 47 GO ON TO THE NEXT PAGE. ACT-65C 4ooooooooo4 Passage Vll Vapor pressure is the pressure exericd by the I'apor above a liquid in a closed container at a giN'en temperature and at equilibrium. Ai equilibrium. the rate of evaporaiio equals Ihe raLe of condeDsatLOn. Two students observed Ihal the i-apor pressure of H:0 decreased %Nhen aCL was dLS501N'ed in the H:0. The stu- dents then offered eKplanations for ￿hY this 'decrease occurred.

Paper 70 · ACT June 2007 · Form 65C · Science Test

A sedimentarv rock .layeT containin.g preseriyed ripples was composed.entirely of sedim'ent parlicles Thith diameters belwcen 0.4 mm and 0.5 The Thraier flow dcpth in the river at Ihe time the.ripples were forming ￿laS beiween 0.1 n and 0.4 m. Based on the informaiion pIescntcd. the velocily of Ihe liver ￿.3[er '3s most likely: trrcater than 0.7 mlsec.

Paper 70 · ACT June 2007 · Form 65C · Science Test

Accordintr 10 the results of Studies l and 2, w'hich of Ihe followinv statements cotnparing ihe maxinum 'aiei velocity at w'hich ripples weie present and the rnaximum Thaler velocity at which dunes w'ere present Kev DO mokeme11 of sediment, llo bedfortns tlat beds dur.es Jelocit%' at which ripples weie pres*nt R.'as higher the correspondiag maxitnum Th'ater Trelocit!. ai ..bich dunes were present. 'elocity at which ripples were present ￿'aS lower than the correspondin£ maximum wateT I'clocits at ,hich dunes ￿le.re present." mLim ￿'ater N clocity at which ripples w ere present 'a5 hiuher th&n the correspondinu maxLmum 'ater velocity at which dunes wert pfeJenl. mum water ￿t10ClLY at which ripples V4'ere piesent was lower than th= corresponding r£iaximum w'ater :elocitv at which dunes ￿ere piesent. i2. According io the reslllts of Study 3, for 2 gii'en ￿'aler velocity. as tbe ￿ ater flow'depth increased, the t}'pe of bedfoim present= chan(yed froffl ripples co dulles. chan CTed froni dunes to flat beds. changed trom flat bed5 to dunes. did not chatkoe.

Paper 70 · ACT June 2007 · Form 65C · Science Test

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Paper 70 · ACT June 2007 · Form 65C · Science Test

Consider the ai'erale wavelenoth of a ripple bedforrn and the average x¥"ai'elen¢Nih of a dune bedfoiEn, as sho￿n in Figure l. M'hich. if eiiher, is(are) vreater than Locm? and th- average wavelen(yih of a dune bcdforn bedforrn nor the aNera8e wai'elength of a dune bedform

Paper 70 · ACT June 2007 · Form 65C · Science Test

Which of the following diatrram5 '"besi illustraies hoTh' Siudeni l u.ould describe the change ihat occ.ars when hack is dissol&cd'in H O ? Key x solute particle o solvenl rnol-cule solulc added Srudent I SolN"enl molecules are attracted 10 charoed solute par- ticles. This causes solN'ent rnolecules io surround solutc parlicles. formincp clusters. AddiE10n￿ enertty is necded LO break solient molecules free frotn thes¢ clusters. Thus, at a gii-en ternpe12ture, Ihe vapDr pressure of the solution is lower Ihan that of the pure liquid. The vapor pressure decre15es as the concentration of charged solute particles increases and as the magniiude of the charge on each solute particle increases. Neuiral solute particles do not affect the i.apor piessure of a liquid. solute added solute added Student 2 Vapor pressure decreases because some of Ihe solirent particles Ihat ha3'c sufficient eller(ry to èscape thc solu- tion's surface collide wiih Ihe solute particles and lose energy. Thus, ai a given temperature, the N'apor pressure.of the solution is lo"I'er Ihan thaE of the pure liquid. The size of ibe decrease in irapor pressure is diiecily proporlional to the conceitr2tion.of sol'uie particles. -4 neutral solute parti- cle decreases the N'apor pressure of a liquid bTr the sane amount as does a charged solute particle. The concenLra- tioll of soluie pailiclts is the only facior Ihat affects the vapor pressure of a liquid. solute added

Paper 70 · ACT June 2007 · Form 65C · Science Test

Do the 2 students difier in their defcripiions of how soIN'ent rr(olecules interaci wilh soluie piriicles in a solution. aEiracted io charged solute particles and Student 2 does not. aiiracied 10 charged solutc partickes and StudellL I does Dot. urround charged soluie pariicle5.. soli.'eni molecules with solute particLes. Experinzeni Three I ko solutions w'ere rnade by dissolvin17

Paper 70 · ACT June 2007 · Form 65C · Science Test

Bas-d on Table I, how did Ihc concep.Iration of soluie particles in Soluiioll 3 cornpare 10 the conceniraiion of soILiie paliicles in Solution l ? The concentration QL soluie particles in Solution 3 ￿as. fewer solute parlicles than does each glucose molecule. solute particLe5 Ihan does each glucose molecule, feM."er solute pariicles than does each gluc05e molecule. hioher, because each Carl, uiii dis<ol&'es irilo moAe soluie particles ihan aoes each .glucose molecule. Table I Solulion Soluic Resulting soluie parLicle(s} I particle (l .neutral glucose molccule) 2 particles (l Tria" and I CL-) J particles (I Ca . and 2 Cl-) trlucosé CaCI 48 GO ON TO THE NEXT PAGC. AcT￿sC 40000000004

Paper 70 · ACT June 2007 · Form 65C · Science Test

Suppose all experiTnent shoNN'ed that each lia- in a sali- "aier solution exists in a clusLer with 3 H.0 mole- cules. This finding would support the explinaiion(s) of Mihich of the studenis, if eiiher?

Paper 70 · ACT June 2007 · Form 65C · Science Test

Iyhell Eable SLTvar is dissolved in pure H O at ?5°C, the vapor pressure at equilibrium is lower than that of pure H O at 25°C. Because dissolved iable sugar Tholecules are neutral, this obseri-ation confTadEcrs the exp13na- ion of: chatged solute particles can cause Ihe N'apor pres_ sure to decrease. charged solute paTticlcs can cause the vapor prcs- sure 10 decrease. uncharged soluie parlicles can cause the ￿apOr pressure to decr-a5e. SiudeDt 2, because Student ? claims that only unchartrèd solute particles can cause the N'apor pressure to decrease. Il"'hich of the following equations is most consisteni with Siudeni 2's explanation? ,J. AP=kxC END OF TEST 4 STOP! DO NOT RETURN TO ANY OTHER TEST. AGr.6sc 49 ' Forni 65C (June 2007) Picturing the Past Math Re2din Science l) A

Paper 70 · ACT June 2007 · Form 65C · Science Test

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Paper 70 · ACT June 2007 · Form 65C · Science Test

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