ACT Past Papers with Answers

Paper 69 · ACT December 2007 · Form 65E · Science Test

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Paper 69 · ACT December 2007 · Form 65E · Science Test

D

Paper 69 · ACT December 2007 · Form 65E · Science Test

Suppoie the scudeiits had placed the 4 wrapped bricks used Èn Experiment l on Ihe table and shoved each of Ihese bricks, causino che bricks 10 slide alotLQ (he table ai Ihe same iniLial speed. Based on the re5ulis of ExpLriment l. Ehe brick wrapped in ivhich paper would most like1￿. ha￿'e l&'Aen the least amount of time 10 come 10 a compleie slop. Table 4 Force Speed Ncedium (N) Vaxed paper B ascd on the results of Experitnenis l and 4. IN'hat ivas the effeci, if any. of a brick's speed on Ihe atnouni of Ih- friciional force on che brick? increased as Eh= brick's speed increased. decreased 35 the brick's speed inLreased. then increascd as the brick's speed inireased. l. Which of ihe folloN¥'ino ranks Ihe diftereni types of paper used to H'rap the brick-s in order, from the paper Ehal presentcd Ihe Itasr resistance to slidino to the paper Ihai presented the ¢yreaiest resisiance to slidino? .4. BrO￿.n paper, n>wspaper, notebook paper, wa,Ked paper paper C, h'otebook paper, M"a,Ked paper, brown paper, newspaper papei

Paper 69 · ACT December 2007 · Form 65E · Science Test

A

Paper 69 · ACT December 2007 · Form 65E · Science Test

The rnic in purpose of Experimcnl ) Ivas 10 deiermine Ihe dependence of (h= amounl ot Ihb frictional force on Lk'hich of ihe to110￿.in￿ i'ariLibles? The aniount of force exiried on Ihe slacked bricks by (he sprincr scale 39 GO ON TO THE NEXT PAGE. 40000000004 Passage 11 Kev Hivh concetRtralions of fecal coliforms in the ivater of a lakt are a hazard 10 humans swimmino in ihe lake. Fecal coliforms Lire b.gCteria foiind in the intesiknes of all endoihermic animals. Tk410 siudies in 2001 examined fecal colifortn concenlraiions in suiface ￿'aler samples fiom a laroe fre5hivater lake and lis tributary 5tream5. samples collecied on a d231 of.. fair w'eather rainy weaiher i 00,000.000 io,000,oc

Paper 69 · ACT December 2007 · Form 65E · Science Test

Accordino EO the results of Stud), I, Ihe increase in ihe 2ver2oe fecal coliform conceniraiion for ￿'aler samples from Ihe dcsicinaled swimming area i￿.2$ oreaiest between w'hich of Ihe folloii'ino dates. Srudv ? In Jul!, on Ihe lasi of 14 con5ecutiire da}'s of fair eaiher, l 00 inL M'ater sample5 Nvere collccttd from each of Ihe folloiL'inLT siles Ihe de%jonaled sw'irnmino area, 6 lak-e sit￿$ Ihai Th'ere ouiside Ihe desionaced s￿,1mmIng 1rea, and each of Ihe 13ke S 5 tiibutary Alieatns. Sei'eral 100 o samples of sand from ihe beach al the desionaied sw'immill(? area th'ere also collected. A second set of saiiiples was collecied ai Ihe same sites on 2 rainy July d2y, Ihe lasl of 7 COF]secutiN'e dai's of rain. T-he sainples ￿'ere analyLed lo detwrmine the ai"traoe fecal coliform concen- trailon (See Fioure ?). The heaN'y, dashed, horizontal line in FicFure 2 represents Ihe fecal coliform H'ater qualii). siaii- dard for Ihe lake. If Ihe averaLTe fecal coliforrn concenira- lion for water samples collecied from ihe I,Ik'e on a parlicular da!. exceeds this lei'el. all swimniino in the lake is prohibiied for Ihal day.

Paper 69 · ACT December 2007 · Form 65E · Science Test

9N Expgrimenr 4 The brick that was wrapped in brown paper wa5 pulled across the Eablc at a constant medium speed and then ai a con>tant hioh speed (see Table 4).

Paper 69 · ACT December 2007 · Form 65E · Science Test

Given Ihe information about Study 2. which of the followinv statements best explains why.the dashed, horizonlal line in Figure 2 does not extend across the bars for the samples frotn ihe beach at the de5i0nated swimming area. ectothcrmic animals. Vater samples. only.

Paper 69 · ACT December 2007 · Form 65E · Science Test

Which of the followin(y hypotheses was most likely beino iested in Siudy 2 ? depth of the lakc water. pH of Ihe lake water. 'eaiher than durino falr weather. than durin(y Au(YUs1. i(x) as hi£yh. as hitrh. io 100 times as hitsh. 41 GO ON TO THE NEXT PAGE. 40000000004 Passage 111 Kei, sucrose Amoleis6x 10 molecules or formula unils of a compound. Thus. Ihe number of sucrose molecules in I mole of sucrose equals the number of N2CI iinits in mole of Nacl. Molality (m) is a unil of concenlraiion defitied as: 23 N2CI C2CI Tnoles of solute kg of solvent When a substancc is dissolved in a solvenl, the freez- ino and boilincv points of the solution will differ frotn those of rhe pure solvent. These chanoes depend on ihc concen- tration of solute particles in Ihe solution. Figures l and 2 show how the freezing point and the boiling point, respec- lively, of H O at l attn of pressure vary with concenlration for 3 soluies. I lJ).4 Key sucrose Ic().o

Paper 69 · ACT December 2007 · Form 65E · Science Test

Would the presence of large numbeis of 8e85e in and around Ihe designated 5WitnminLT area throughout the Sutnmer of 200 I likely have had any effect on the fecal coliform conceniraiions measured in the studies? a source of fecal coliforTnS. source of fecal coliforms. source of fecal coliforms. sourct of fecal colilorm5.

Paper 69 · ACT December 2007 · Form 65E · Science Test

A comparison of ihe average fecal colifortn concentra- lions gi%en in Fioure 2 for the fair-weather samples shows that.'relaiive to the concentration for the Iribu- tary streams, the concentration for Ihe lake sites oui- side the desi(rnaied swimmino area.w as approximal-ly:

Paper 69 · ACT December 2007 · Form 65E · Science Test

Based on Lhe trends in Figure ? which of the following aqueous solutions would have the hivhest boiliniT point?

Paper 69 · ACT December 2007 · Form 65E · Science Test

For Sucrose. which of the lollowinty values is sufficient to convert the i'alues on the x-axes of Fioures l and 2 to grams of soluie per ku of solvent? Atomic number

Paper 69 · ACT December 2007 · Form 65E · Science Test

D

Paper 69 · ACT December 2007 · Form 65E · Science Test

Based on FiTrure I, as the mass of sucrose dissolved in a oiven amount of solveni increases,'the freezing point of the solution will-. increase linearly. increase. bul not linearly. decreasc, but not liniarly.

Paper 69 · ACT December 2007 · Form 65E · Science Test

A studcnt clairned ihat. per formula unit. addincp N'acl chancyes the boilincy point of H:0 more Ehan addilltr Cacl: Does Fiuure 2 support Ihis claim? smaller increase in the boilin￿ point. smaller decrease in the boilino a poini. orèater increase in the boilino point. LTreaier decrease ITh Ihe boilino poinl. li. Based on Fioure I, Ehc freezino point of a solution composed ol"1.20 moles of Nacl dissolved in I ku of H,0 %¥'ould be closest to which of Ihe folloivinLT? -5.7°C -4.3°C -3.8°C ACT-6iE 43 GO ON TO THE NEXT PAGE. 40000000004 Passage IV 40 distance: 40 disiance-. Wind spread ash from a volcanic eruption eastward oN'er a laroe area. An ash sample was collected at each of i differeni disiances easl of the volcano. The diarneters of Ihe paiticles in each sample were deieitnined 2nd con- i'erted phi (see Table l). Fioure I shows the wcicphi per- cent of each sample's ash particles belongino in each of 10 different ranges of phi (see FiLTure l). 30 30 20 20 10 -10 123456789 phi 10123456789 phi -.40 distance: 40 disiance: 30 30 20 20 10 1 ?3456789 phi 101?3456789 phi 40 di51ance'. Table I Particle diameier (mni) 10 Converts to a phi of- 1 0123456789 phi

Paper 69 · ACT December 2007 · Form 65E · Science Test

FiGure ? indicales thaE, cotnpared with the sample col- Ipcted closest to the i'olcano. the sample collected far- theit frotn the volcano coniained hioher w'eioht percents of: rock frautnencs and glass shards onl).. rock fra(yments and feldspar cr)'slals only. lass shard) and feldspar crystals only. olass sha,-d> and niafic cr)'sials onl). 40 10 feldspar tnafic CF!Slals Crysfals fFatitnenls shaids

Paper 69 · ACT December 2007 · Form 65E · Science Test

Accordinu to Fitsure ? rock fraomeElts in the ash sarrLple collected at 160 km east of rhe i'olcano com- prised approximaiely 54.hal percent of the saTnple's 'ei(yhc? ?? A sludLnt claimed thai if che ash pariicles in the sample colleci-d closesi to the N'oliano are compared Ii'iih Ihose in Ihe sample collecied f&rihesc from Ihe -OIc￿*nO, th￿ i¥'eiahi percent of laroer parcicles will bc hLcrh￿C li Ihe sampl¢ collected closeit to thc i'olcano. Is Ihis cliim %Lipporied bj, Table l and Fi(Fure l ? 'D-. Ihe ￿1)I￿h[ perceni of O-J phi pariicles was loiier ?7 km east ot Lh. volcano than it 'was

Paper 69 · ACT December 2007 · Form 65E · Science Test

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Paper 69 · ACT December 2007 · Form 65E · Science Test

Based on Fi(7ure 2, which of ihe following f£(yures best repiesents Ihe weitshl percents foi the 4 ash parlicle types in the sample collected 18? km cast of the volcano. 40 80 70 ?0 60 &40 rock fraotnenls shards feldspar tnafic ryscali Crystals 40 10 10 50 100 150 200 250 300 3iO 4Crf) 450 distance easL of i'olcano (km) I Weioht percenl is the percent of a sample's weivht from particles of a specific iype. Fioure 2 rock fragnenis shards feldspar mafic crystals Cryslals 40 30 Figures adapt<&d from Steven Carei and'Plaraldur Sigurdsson, "Influence ol Par'Licle Aggregalioii on Daposilion ol D sial Taphra fioffl Ihe May 18, 1980, Eruption ol Mount St. Helens Volcano. Q)1982 by iha American Geophysical Union. 10 feldspar rnafi cr)'stals Crystals frapmtnls shards

Paper 69 · ACT December 2007 · Form 65E · Science Test

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Paper 69 · ACT December 2007 · Form 65E · Science Test

Which of the folloii'ino most lik-elv explains ii'hv ihe researchers included Treaimenl l in Ihe expeiiinenl.. determine hoii, the oiher experimental treatrnenls affected populaiion den£it¥'. maximum Iiunber of snowshoe hares that can sur- i'ii-e oil a I k-ni x I km plol. of lood that should be added 10 the plois Ihat li-ere asfioned Lo TreatrnenE ). types of food calen b), s￿O￿.ShOt hares oK'er Ihe course of a J'ear. Population density of Trealmeni I plois .{hares/hectare) Year For each )'ear, the researchers defined Ihe populatlGn deiisili. ratio for a c1kN'en trLatnieni as be2ntr equal to Ehe N'alue of ihe folloii'inoT expres£ion: ai'erat)e popul 31ion densii¥' ol Ihe i pl ots a55i9ned 10 the ireatrnent ai'eracfe. populalion densil), of thc 5 plois-assi uned to Tre3tmenl I ?4. Ivhich of the follo￿,in0 niost lik'ely identifies a crroup of animals Ihat Ihc researchers attempted to exclude from the plots afisitrned to Treatment 4 ? Acf45E 46 GO ON TO THE NEXT PAGE.

Paper 69 · ACT December 2007 · Form 65E · Science Test

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Paper 69 · ACT December 2007 · Form 65E · Science Test

Treatment 3 was most likely included in the experi- ment to investigate which of the following questions? consume in natural environments? . hares for vegeiation? growth rate of vegetation in forest plots containing snowsboe hares? plot affect the population density of snowshoe hares?

Paper 69 · ACT December 2007 · Form 65E · Science Test

Prior to performing the experiment, each of the 4 rcscarchers proposed l of the following bypoihe>es. Which hypothesis is besi supported by the results? lion density of the snowshoe hares. hare populations more than will adding fertilizer to the plots. tbe population density of the soowshoe hares. snowshoe hare populatious less than will addinL7 fertÉlizer to the plots.

Paper 69 · ACT December 2007 · Form 65E · Science Test

Which of the followintr ranks Treatments 2-5 from the treatment that.had .the greatest effect LO the treatment that bad the leasc.effect on Ihe popularion density of snowshoe hares during Year 5 ?

Paper 69 · ACT December 2007 · Form 65E · Science Test

T￿.0 treatments are synergistic if Ihe effect of combin- ing tbe treattoents cxcceds the sum of the ctfects of each treattnent individually. The desicrn of the experiment allowed the researchers to itLvesiigaie whether which of the following pairs of treattnetEis aic synergisiic? cr.￿E 47 GO ON TO THE NEXT PAGE. 40000000004 Passage Vl Ozone (03) is concentrated in a part of Earth's aimo- sphere called ihe ozone la):er. 03 absorbs harmful high- energy solar radiation. Unusually low aniounts of O have been detected over Antarctica each spring since 1978 in an area of the ozone layer called the O£one hole. Two scien- tists hypothesize aboul Ihe cause of ihe ozone hole. Scienrisz I Chemicals known as chlorofluorocarbons (CFCS), such as CF Cl2 and CFCI , are responsible for the forma- tion of ihe ozone hole. CFCS have been widely used as refrigeranis and aerosol propellants since their introduction irt ihe 1930s. CFCS accumulate in the atmosphere. where (7ht) breaks them down 10 produce chlo- solar radiation (li. rine atoms (Reaction l): Scienfist 2 The total amount of 03 in Earih's atmosphere is con- slant. O concentrations vary over Antaictica periodically because wind CU￿entS cause local chanocs in the amounts of all thc chemicals ill the atmosphere.°.Though. CFCs-can break down 03 by Reactions'l-4, Ihe C]O..produced in Re2Ction 2 mosily re2Cts wiih ihe abundant nilrogen oxides in the atmosphere. Reactions 5-7 show how CIO reacts with NO to Tegenerate O (5) CIO+NTO->Cl+NO (6) NO2 + lioht -> NIO + O (7) O+O,->O CIO can also react with nitrogen dioxidc to form chlorine nitrale (Reaction 8): (i) CF2CI2 * light -> CF Cl + Cl (8) CIO + NO -> CINO, Tbe unstable Cl atoms reaci wilh 03 to produce chlorine monoxide and O (Reaction 2): CIN'O does not react wilh O so il stops the chain reaction shown in Reactions 2-4 from breakincr down large amounts (2) Cl+O,->CIO+O, The 02 is Ihen broken down into O atoms (Reaclion 3): 02rlight->20 (3) The unsiable O aloms then react with CIO to produce mor Cl atotns (Reaction 4): (4) O+CIO->Cl+O, Reaclions 2-4 make up a chain reaclion, because the Cl atoms produced in Reaction 4 can then react with Thore in Reaciion 2: (2) Cl+O3-ICIO+O [3) lighi -> 2 0 (4) O+CIO->Cl+O

Paper 69 · ACT December 2007 · Form 65E · Science Test

According 10 boih Scienlists l and 2. which of the fol- I0￿,1n£T substances rnust initially be present for CIO to bc produced by CFCS in Earth's atmosphere? Thus, the Cl atorn produced by I CFC molecule can break down large amounts of O . Due to competincr reaclions, this chain reaction does gradually slop if the number of Cl aioms produced decreases. bui ihi5 slowdown takes many )'ears. cr-65 48 GO ON TO THE NEXT PAGE. 4000000000

Paper 69 · ACT December 2007 · Form 65E · Science Test

Which of Ihe following graphs would Scientist I most likely use to show how the total amount of 03 in Earth's atmosphere would change a5 Ihe amouni of CFCS introduced inio Earth's atmosphere incrcases?

Paper 69 · ACT December 2007 · Form 65E · Science Test

A ch".misi claimed ihai a molecule of thc product in Reaciion 8 ￿,111 haN'e a oreater mass than a molecule of eiiher reactant in Reaction 8. Is her claim correci? dops a tnolecule OF either product. docs a molecule of either reaclarLI. D, Ye). a molecule of CIO has a greater Tnass than does a molecule of lio 3i. In which Df the followino ways could Reaciion 8 iii Scientist 2's h)'poihesis coniradicl Scieniisi I's hypDIh- esis? The chain reaction shown in Reactions 2-4 will noi occur if all of the- O? produced in Reaciion 8 reacts ivith Clo. 49 GO ON TO THE NEXT PAGE. ACT-65 40000000004 Passage Vll Ferromagneiic materials become magnetic when they are placed in an external magnelic ficld. Figures l and 2 are graphs of the loral magneiic field, versus the intensity of the exiernal magnetic field, H. for Materials X and Y. iespectively. (B - Ilo IM + H]. where Vo is a consLanl and M is the magnetization of the material.) B varies as H is increased from zero, then decreased. then increased again, as shown by Ihe directions of ihe arrows in the figures. If B is no£ zero when H ieturns to zero, a material has been magnelized. When B or H is posilive(negative), it is described as pointino north(south). 25,0 | 500 750 H,, intensity of external field- ampereslmeter) Figure I MATERIAL Y -1,000 -2iO 250 i 5C)O 1,000 (atnpereslmeier) I Figure 2 ACT-8SE 50 GO ON TO THE NEXT PAGE. 4000000000

Paper 69 · ACT December 2007 · Form 65E · Science Test

If all use of CFCS were stopped, ScienList I would mosi likely predict that which of the followin(T chanoes would occur in the total amount.of Cl-containing compound5 and the lotal.amounl of 03 in Earih's atmosphere? pounds and 03 would eventually increase. pound5 and O. would eveniually decrease. would eventually incieas- and the total amount of would stop increasini would ei'eAiually decrease and the total atnount of would stop decreasino amount of CFCS

Paper 69 · ACT December 2007 · Form 65E · Science Test

Scientist 2 would most stroncrly dtsagree with which of the followintr statemenis about O in Earth's atmosphere? of O in Earth's atmosphcrc. from season 10 season. sphere is decreasing. amouni ofCFC5 34, Afier examininu Scienlisi 2's hypothesis. Scientlsl 1 claimed thal Reaciion S would causc further O deple- tion. How would Scientist l.most likely defend this amount of CFC5 react WlLh O in Reaction 2. react wich CF Cl LO produce CF CI:. so little O can be re(reneraled. Reaclion 5 causes Ihe amount of NO to decrease, so not enouoh INO can be produced for Reac- tion 6. amount of CFCS

Paper 69 · ACT December 2007 · Form 65E · Science Test

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Paper 69 · ACT December 2007 · Form 65E · Science Test

B

Paper 69 · ACT December 2007 · Form 65E · Science Test

For Material X, the maximum positive value of B was obtained at an H closcst to: +100 ampereslmeter. +200 ampereslmeter. +300 ampereslmeter. 400 ampereslmeter.

Paper 69 · ACT December 2007 · Form 65E · Science Test

Accordincy to FicTure I, for Material X, w'hen H was increasincT from ils mosi negaiive value and had a value of O amperes/meler, B had a value closest io: +1.3 T. +0.5 T. -0.7 T. -1.1 T.

Paper 69 · ACT December 2007 · Form 65E · Science Test

The remanerlce of a material is Ihe v.alue of B when H reaches zero after H has been decreased from ICS maxi- rnum positive value. Acio[din￿ to Fitruie ? Ihe reroa- ncnce ot Material Y was clDseil to:

Paper 69 · ACT December 2007 · Form 65E · Science Test

For a new ferromagneiic material, Z, a partial graph of B veisus H is obtained. If Maierial Z behal'es. Iike Materials X and Y when H is varied as shown in Figuies l and 2. Ihe remainder of the gL aph of B I'ersus H for Material Z will look most like which of the followin

Paper 69 · ACT December 2007 · Form 65E · Science Test

Consider ihe mosi positive value of B and the most negative value of B on tb.e oraph in FicTure l. How are Ihe)e Iwo values of B selaied? The mosi negaiive value of B is equal to: I lirrLes Ihc most positiyc value of B. +1 times Ihe tnosÉ poiÈCive value of B. I divided by Ihe most posiiive value of B. +1 divided by Ihe most posÉtive %'alue ol B. END OFTEST4 STOP! DO NOT RETURN TO ANY OTHER TEST. ACT-g?¥ 51 .iE (December 2007) .de Contents Math Readin Science l) A