ACT Past Papers with Answers

Paper 65 · ACT December 2008 · Form 67A · Science Test

Consider the trials representcd in Figure l inyolving 20 g of LICI. From trial to trial, as the LICI concentra- ".tion in ,the resulting. solutions increased, the. 1ST that was observed: y increased only. increased, then decreased.

Paper 65 · ACT December 2008 · Form 67A · Science Test

5ft ground Figure I A cap]era.mounted ou the launcher always pointed in the direction of the ball's launch. A radar transceiver (transmitter-receiver) was also mounted on the launcher. This procedure was followed. for launch¢& of the ball at.speeds of 80 mph, 90 mph. IOQ mpb. 110 illph.. and | 120m

Paper 65 · ACT December 2008 · Form 67A · Science Test

. According to Figure 3. when. 5 ,8, of ..NH4NO3 was .added to'lOO g o! H O. the tewperature of.the solution: . G. .. decreased, because "LIT was negatiVF.. ..increas¢d, because thT was Positive. inCre￿ed. because was negative. "3. If an additional trial had been, done in"which 25 8 of LICI had been. added to 75 8 of H O, tsT would most likely.have been: , 5. Based on Figures l and 2.:wbich of the following com- binations of a solute and H O*at a known Ti would pro- duce the greatest increase in temperature7. 'B. 2 g of LICI added to 10 g of H,0 ACT47A . 39 GO ON TO THE NEXT PAGE. 40000000004 Passagè11 ' . During propbase I of meiosis. homologous chronio- '30mes. frequently exchange segmènts in a process called crossing over. As a. result.. genes on homologous clLromo- "somes rtcombitte. foTULing new allele combiuations along. chromosomes (see Figure l). 0 2Q. 40 60 80 1(KI. 120 140 160 180 200 Ma￿ distance (mu) homologous cl)romosomes before crossing over occurs Figure 2 Four rescarGh¢rs perfornied a series of experinwnts'to determille the.RF. fot,vwous pairs of genes on a clwoLUO- . some. They then .used the mapping functign to: determine the map distance betweeo each pair:. Th"e results appear. in .Table l.. crossing over Table I . Map distance (mu) 20 30 . fjenes AandB AandD RF.: Q.122. hornologous chromosomes . ".aftet crossing over occurs Each of thc 4 raearchers then proposed a model that. is consistent with the results in Table l. Each. model shows ' how the gents Itiigbt be located along the chromosome (see Figure 3).'Each' model correctly assumes the lengthg o! the genes are short enough that they. can be ignor¢d wheo cal- "culating the map distance between genes. Figure I Researcher Model Because the frequellFY. of recomblllation ' (RF) increases as the map distance (distance along. a chromo- some, In map units.[mu]) between 2 geDes'incteases, RF can be used to estimate the.map distance between genes on a chromosome. However, as the ffjap distance between 2 genes increasés, the probability of myltiple crossovers increases. Multiple crossovers decrease the apparent RF between 2 genes, Tesulting in RF values".that underestimate map distance. To c.ompensate for this effect, researchers .use a mapping fijnction to better estimate the map distance between 2 genès based on their RF (see Figure 2). DCA. C A.DB . Figure"3 Later, a fifth res¢archer working with the same chro- mosome and the same genes deterniined that the. RF for Genes A and C is 0.091. ACT47 40 GO ON TO,THE NEXT PAGE. 40000000004

Paper 65 · ACT December 2008 · Form 67A · Science Test

00

Paper 65 · ACT December 2008 · Form 67A · Science Test

. All 4 models a8ree.on'the map dIs￿ice between ivbich "of th¢ following pairs of genes? 'J. Genes C and D . 10. Based . OD the infoImation.. provided,. crossing over occurs during the process'that leads diT¢Ctly to the for- rnation'of wbich of the followillg? .H. ' Erythrocytes .7. . According to Figure 2, if 2.genes 'are separated by, 70 mu. the.RF of those 2"8enes is most likely. closest to. whick of the following. .A. 0.377. . B.. 0.477

Paper 65 · ACT December 2008 · Form 67A · Science Test

A

Paper 65 · ACT December 2008 · Form 67A · Science Test

If Researcher" 2's model is correct and 2n additional gene. Gene Q, is 8 inu from Gene B and 14 mu from . Gene D. then Gene G is most lik¢ly between: ' F. Genes A'and B. l?. Genes R and T ar¢:separated by 10 mu 'on I chromo- some. An. organism has=alleles R and T.,oll I chroJno- some and.alleles ,r and t.on the bomologous chromosome. If a single crossover occurred between these 2 genes as shown in Figure I,,th¢'genotype of Genes R.and .T for the 2 chromatids involved in the crossover would be: ' G. RT and.rt. ' H. Rr and.Tt.

Paper 65 · ACT December 2008 · Form 67A · Science Test

The result of the mapping. exp.eriment performed 'by the fifth researcher for G¢nes A and C is consistent with the models proposedly which 2 researchers? .C. Researchers 2 and. 3 . 41 GO ON TO THE NEXT PAGE. 40000000004 Passage111 Pore. w.ater is .wat¢r" in the pores of .subsurface material. Pore water chemistry in 2 wetlands-a fen and a bog-was studied during a 199(6'summer drought and again the next summer, wlllch had normal [￿nfall. The primary . water supplies for fens and bogs are, respextively. ground- .water attd rainfall. Figure I shows the methkne (C￿) gas concen¢ration in the pore water at various depths. in the fen and the b.og. Figures 2. and 3.show the porè water conduclivity .(iwhich is directly proportional to the ¢oncen- tration.of dissolved ions) 3nd pH. at various depths in the fen and the bog,.respéctively. 'A]so shown are the locations of the water table. the peat (partially decomposed. plant .material) layer. alld thé mineral soil layer. 5uuunei of 1990". -.summff of .1991.. . water .table fen '.bog

Paper 65 · ACT December 2008 · Form 67A · Science Test

F

Paper 65 · ACT December 2008 · Form 67A · Science Test

Which researchér's model proposes that Genes C and D are S￿arated by 64 mu ? . C. Researcher 3's . D. Researcher 4's

Paper 65 · ACT December 2008 · Form 67A · Science Test

G

Paper 65 · ACT December 2008 · Form 67A · Science Test

According to Figure 2, the conductivity of fen pore water in 1990 at a depth of 2.5 m was closest to which of the following. . 16. If the data in Figures 2 and 3 are.typical ￿f fens and ,. bogs.in general, one .would inost.likely ￿lake whicb of . .. the.followAng.£onclusions about.the peat.layer in a.fen ' alldinabog. . pletely above the water table &t all times. .G. The peat layer in botFi A fen and a bog is con]- pletely below. the water.table at all tinies. . layer in a.bog. layer in a bog.

Paper 65 · ACT December 2008 · Form 67A · Science Test

Based on Figure 2, if the PH of porè water in the fen at a depth of 2.7 m had be¢n measured in the SULnmer of . 1991, it would most. likely have been closest to which of the following.

Paper 65 · ACT December 2008 · Form 67A · Science Test

which.of the following is the most likely explanation for the differeDce in the depth of the bog water table in the 2 yèars? was bigher during the drought, and.therefore the bog r.eceived.more water than nonnal. was higher during the droughi, and therefore the .bog received less water than nornial. higher'during the drought, and therefore the bog received more water than normal Jower during the dro)ught, and therefore the bog received less water than normal.

Paper 65 · ACT December 2008 · Form 67A · Science Test

H

Paper 65 · ACT December 2008 · Form 67A · Science Test

According to.Figure I, the average coocentratson. of CH4 over the depths from 0.0 m to 3.0 m ivas higher during the summer of,. Doimal rainfall than during the summer of drought in both wetlands. nonllal rainfall than during the summer of drought in the fen only. in both weuands. in the bog only. 43 GO ON TO THE NEXT PAGE. 40000000004 Passage IV Atomic nuclei 'can be. represented by the combination of symbols

Paper 65 · ACT December 2008 · Form 67A · Science Test

Which of.; the.following- symbols correctly represents the isotope of radium (Ra) that is part of the'radioac- .tiv¢ decay sequence plotted in Figure I ,? 226 where Z is ttLe number o'f protons tn a nucleu4 of Element X, and A (equal to z.plus the'number of neutrons) is the .mass 12 number of the same nucleus. For example. 6¢ r¢pre$ents a 14 nucleus of carbon containing 6 protons and 6 neutrons; 6 .represents a nucleus of a different isotope (type) of carbo'n. tbat contains 6 proton4 and 8 neutrons. Atomic nuclei undergo 3 typcs of radioactive decay. ' Particles emitted duriilg the 3 types of decay are listed in Table l. Figure I shoiws a sequence of radioactiv.e decays, called the uraniu7ii series, that begins with the decay of 238 92 88 226 Table I Type of radioactive . decay Symbol of , ernitted particle Particle.émitted Alpha Beta helium..nucleus

Paper 65 · ACT December 2008 · Form 67A · Science Test

How many.neutrons, if any, does a nucleus of the iso- . tope. of helium listed in Table I cotitaiR? electron ,Gamma ' gamma ray photoo elcment U Pa Th Ac Ra Fr Rn AtPo'Bi'Pb Tl" 242 .238 Key (L- alpha decay. beta decay. 234 230 226 222 218 214 230

Paper 65 · ACT December 2008 · Form 67A · Science Test

Based on Figure I, if a nucleus of" . Th underwent 90 beta decay, which of the following nuclei. would be produced? 230 210 206 202 93 92.91 90 89 88 87.86 85 84.83 82 81 80 91 91 Th Figure I ACT47A GO ON TO THE NEXT PAGE. 40000000004

Paper 65 · ACT December 2008 · Form 67A · Science Test

A iample of spent nuclear reactoI fuel contains a mix- 235 . ture of a-￿a￿luM isotope> ￿U, and a. plUtO￿uM iso- 239 , tope,- 94Pu.'Based on Table l and Figure I, if .one. of ' the isotopes is produced by :tlie radioactive decay .of the other isotope',.which of the foltowing best e¥plaillS how the mixture was fornied7 .. 22. Suppose the. 2He nucleus..emitted during an. alpha decay.and the.e .emitled,durillg:a .beta.decay,have. the same..kinetic.. :energy. . Which . of '.the. 2, particles" ,is.' moving.'at the bigber.speed? .235 239 92 U un'derwent alpha decay, producing 94Pu. 239pu underwent alpha decay, producing 233 44 235 239 92 U underwent beta decay, producing 94 239 .235 94 Pu underwent beta decay, producing 92 thee . H. Th"¢ e. . because it is.more massive.than the 2Hé nucltus. nucleus. ACT47A . 45 GO ON TO THE NEXT PAGE. 40000000004 Passage V. .. Size exclusion chromatography (SEC) is used to sepa- rate the components of a.solution of polymer molecule&:. In .SEC a sample solution of polymer molecules is Injected into a floiv of solvent. The sample is then carri¢d through a (see Figure l). Exi>eriment I .'Polystyrene is a polymer, made,'.up of .identical .sub-. units. Fiv¢-types of:polystyrene:'(Pl-. PS) were. dissolved ' together in a solvent.. The.AMM of P'I-P5 is .given in:. Tabl&. l..:The range.of molecular. niasses forEach.of PI-P5 , was *IOO amu of the AMM." sample solution pump solvent . Table.1 detector AMM . (amu.) column packed with beads Poly.styrene pi .800 4,000 . 10,000 50,000" . 200.000 Figure I Smaller moleculcs easily diffiise into the pores. Larger molecules do not as easily diffuse into the pores. or are "larger than the pores. Therefore, smaller .molecules spend more time in the column than do larger molecules, causing Ihe. comyonents of the mixture to separate. As.solvent con- taining a component of the mixture exits the column through the detector, a peak is plottea versus tsme (starting from injection). The portion of 'solvent corresponding to a peak is called afraciion. The time corresponding to'the top of a peak.is the fraction's retention lime (RT). The RT cor- responds to the average niolecular mass (AMM) of the . 'molecules in that fraction. The shape of the.peak reflects the distribution of molecular masses of the molecules in the fraction. P3 'P4, P5 atomic mass unit A sample of.the splution was injected into an SEC appara- tus. :Each,fr3ctson was analyzed as it exlted .the apparatus (see Figure 2).. P4 P3 P2•+ 10 11 12 13 14 Irr (min) Figure 2 AGT-67A ' 46 GO,ON TO THE NEXT PAGE. 40000000004 'ExpeTimeni 2 Ch¢mists used 3 different methods to synthesize.poly- styrénes, forming. polystyrene mixtures Ml, M2, and M3, respectively. Each of MI-M3 was then analyzcd as in. Experiment l (see Figure 3). for Ml 10 11 12 13 14 for M2 .10 "11 12 13 14 11 10 11 J2 13 14 Fjgure 3

Paper 65 · ACT December 2008 · Form 67A · Science Test

61 .18.22 '

Paper 65 · ACT December 2008 · Form 67A · Science Test

Based on the results of Exp.erinients l and 2::M3 is . most likely which polymer(s) from Experiment 17

Paper 65 · ACT December 2008 · Form 67A · Science Test

In Experiment l. the molecules- of which of th¢ follow- ing polymers spent .the longest amount of time in the. column?

Paper 65 · ACT December 2008 · Form 67A · Science Test

Based on the re&ults of Experiménts l and 2, which of the following ranks P4, P5, and M2 from Cmallest AMM to lar8est AMM ? ACT.67A 47 GO ON.TO THE NEXT PAGE. 40000000004 Passa@e Vl Tro..studies-examined.,how for¢st fires'would have ' burned during the laté.Paleozoic era,: when Earth's atmo- sphere contained an elevated O, content Of mor¢ than 21% by.volume. Araucaria tree leaves and Pinus tree dowels (wo,od pieces) and needles, au from miidern,trees, were used in the studies to most closely model tr.ees in Paleozoic forests. Study I ..rate of 40:Clmin in an atmosphere containing.2J % 02 ky. volume. Thc mass of the saEnple was measured every .2 sec during heating. 'These. pro¢edures were repeated in a second trial in an atmosphere containing 35% 02 by .volume. .Then each trial was. repeated using a 10 mg sample of paper instead of Araucaria leaves (see F'igure.l). The rate of mass loss. was directly proportional to the rate. of combustion. ._For any trial in which the sample .burned ¢oiiipletelyi . the. flame spread rate.was recorded. ,:Those trials repre-" . sented.¢onditions.:.under :whichva. fore8t,:fire'.'w.ould"haye': &-- . burned. out, of-'control.,.A faiLed-burrt. (F) was,iecorded 'for' j.Y. any '.trial' in .which. the fire..in ,the 'chamber'.extinguisbed-f itself.before the sample burn¢d completely (see Table'l).: Table I Flame spread rate (cmlmin) In an . atniosphere rolltaining: . Water content of: 16%0 28% 0,

Paper 65 · ACT December 2008 · Form 67A · Science Test

In Experiment I, on average, did P3 molecules. or 'P4 molecules more ¢asily diffuse. into the pores of the beads while iri the column of the SÉC apparatus?

Paper 65 · ACT December 2008 · Form 67A · Science Test

In which, if any, of the mixtures synthesized for'EKpei- iment 2 is Ihe av¢rage mass of the molecules in the rnixture'most likely greaterthan 200,000 amu ? ' D.. Neither Ml. M2. nor M3

Paper 65 · ACT December 2008 · Form 67A · Science Test

How does the number of molecules in a I g sample of . ' P2. compare to'the number of molecules in"a I g sampl¢ of P4 ? The nwribei'of P2 molecules is: .F. less. b'ecause P2 has a la.rger AMM than doés'P4. P4. P4.

Paper 65 · ACT December 2008 · Form 67A · Science Test

According to the results of Study 2.. as 02 ¢ont¢llt '.increased from 16% .to 35%, .the flame"spiead rate for dowels having a.water content of 2%: increased only. increased, then aecreased., .

Paper 65 · ACT December 2008 · Form 67A · Science Test

According to the results of Study I, the sample of Araudaria leaves. .heated in an atmosp.here contsining 35% 0. lost mass most rapidly over which of th¢ fol- loviing temperatiire Tanges? . J.. 425°C to 475°C .31. Suppose that the needles. and wood.of a type of .tree . that existed 'in the late Paleozoic era and closely resembled..modern Pinus trees had water contents above 65% by.weight..Bas¢d on Stu'dy 2, would a tree . of that type have burncd completely in an .atrnosphere containing 28% 02 by volume arid in an atmosphere . containing 35% 02 by.volume, respectively? 28% 0,. 35% 0, Yes

Paper 65 · ACT December 2008 · Form 67A · Science Test

B

Paper 65 · ACT December 2008 · Form 67A · Science Test

Suppose that:in.aTr 2dditional.trial. ill 'Stud '. 2, needles , havillg a-,water.content..of ,,10 -by.'weig t.:bad,been':" .burned * in ":.aD.4 athiosphere" :'containiiig .28 volume. .Based on the..results .of::Study .2,, .Ihe'flame". spread Tate .recorded for..£hat tria],.would most .likely have beell: J: . greater than"37.50 cmlmiR..

Paper 65 · ACT December 2008 · Form 67A · Science Test

Consider.a PAleozoic forest t￿e. burriiDg" out of control. in a stand of trees that Closely resembled modern >inus trees. Based on .the.T¢sults.of ,Study", 2 for,an atmo- sphere containing 28 02 and.an :atmosphere 'contain- inÈ 35% 0 , ts it more likely. that the Crnwrt fire"(r￿e spreading .through tbé. live foliag¢ of tr¢es) or the sur- face firé (fire spreadin8 through the. trees just above the groiind). would.haY¢ spread faster? ', A. :Thé crown fire.. becaus¢"thé' flame &pread rates for needles w¢r¢. inu￿ lower .thaD the CO￿eSpOndIng ' rates for dowels. needles were much.higher than the corresponding ra¢es for dowels. Deedles 'weTe" much lo.wer than. the corresponding rates for dowels.. '.needles .We￿ the same as 'the corresponding iat¢s for dowels..

Paper 65 · ACT December 2008 · Form 67A · Science Test

.In Study l-. the paper sample'.heated in an, atmosphere containing .21% 0 had lost approximately wbat per- . cent of.. its ￿nsInal.￿aSs .by, the time .the teitisierature . reacbed 350°C ? Yes Yes th47A .49 GO ON TO TtIE NEXT PAGE. 40000000004 Passage Vll Students studied .:the trajectories of a baseball launched under a variety of.conditioDS. In additioll. every O. S ,sec. after launch,. the. transceiver emitted a radar putse, part of which was.r¢flected .back to the transceiver by.the ball. .TtLe.roiind¥tsip travel time.of , . . each pulse was. recorded." and then used to",deterniine. tts¢" distance., D, between.the.transc¢iv¢r and 4be"ball.-(see., Figure 3). ball Study I On a flat plain during a windless. day,.studtiits launched a baseball using the launcher shown in Figure I". launcher ball Figure 3 camera launcher horizontal plane . Using D and e. the studènts found die ball's height. .H, and distauc< R, at the end of ¢ach 0."5"sec interval. H. was plot- ted versus .R. and a smooth curve was. fitted to the data points. transceiver

Paper 65 · ACT December 2008 · Form 67A · Science Test

Suppose the .ball were launched at 35° in the absellce of air.from a height of:3.5 ft. Bosed on Figure 5,. the ball ￿OUld Irénd approxilliately.how many feet farther from ihe launchei if it iKerc launched at..100 mpb .than if it wére launched at 90 n]ph 7 50ft

Paper 65 · ACT December 2008 · Form 67A · Science Test

While the ball. was. in flight. how"frequently did the . camera record the ball's image? . H. Three tiiiies pér second

Paper 65 · ACT December 2008 · Form 67A · Science Test

Fenway ParL home of baseball's"Boston Red'sox, has a wall in left fieId that is 37 ft high. The distance mea- sured alèng the left field line from home plate to the boiLOlii of the waIl is 310 fi. Assiirne that, on a iiiind- less day, a ball identical to the.one used.in Experi- meDt I leaves a bat at an initial heigbt of 3,5 ft above the ground, at an angle of 35° with respect to tbe hori- zontal, aDd fliès straigbt.along the left field line. The ball will fly over the w￿[ if the ball leave5. the bat at which of .thc speeds given in Figure 4 ?.

Paper 65 · ACT December 2008 · Form 67A · Science Test

Btsed on Figure 4., as the launch Èpeed was'increased, h'ow did H and F at 3 sec after launch vary7 increased increas increas¢d . decreased illcre￿ed . .decreased

Paper 65 · ACT December 2008 · Form 67A · Science Test

-.Based. on Figure .5. if .the ball were launched in the 'absence .of air.fEom a height of .3..5 ft at 120.mph and 8" ':3'5°. h'ow long would the ball most likè'ly be in . flight from. the moment it was launched to tbe momeDt it landed? ..A. Between 4 sec and 5 Sec

Paper 65 · ACT December 2008 · Form 67A · Science Test

Based on Figure 3, if c represents the speed of light, ' how long did it take each radar pulse to inake. the rouud-trip between the trausLeiver and the ball? .END OF TEST 4 STOPI DO NOT RETURN TO ANY OTHER TEST. . ACT47A 51 Forni 67A (December 2008) Miami Time Math Readin Science i) c