ACT Past Papers with Answers

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Table l and Figure I, what is the correct order of the 3 phases of the isometric twitch of the adductor pollicis, from the phase with the shoriesi duration to the phase with thc longest duration?

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to Figure I, during the isornelric twitch of the adductor pollicis, Lhe time that elapses from the start of the twilch until the tnuscle contracts with the greatest forcc is closest to which of the following. 30 msec 90 msec

Paper 52 · ACT April 2012 · Form 70G · Science Test

Source question 4. Refer to the source image.

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to Figure I, during the isometric twitch of Lhe adductoi pollicis, the muscle begins to generate force at approximately which of the following times? 2 msec bcfore the stimulus occurs B, 10 msec before the ,%timulus occurs 2 msec after the stimulus occurs ACT-70G 39 GO ON TO THE NEXT PAGE. 0000000004 Passage 11 In August, the ozone (O ) content of the stratosphere above Antarctica begins to decrease, reaching a mRnimum around OcLober 15. Over this period, winds surrounding this ozone hole keep it isolated frorn adjaccnt areas where thc air has greater 07 content. In late October, the winds weaken, causing the O content of the air in the ozone hole to increase again as this aiI rnixes with the air from adja- cent areas. Figures I dnd 2 show how thc air temperature and 0.7 partial preJ,fure (a measure of 03 content), respec- tively, changed with altitude in a poriion of the strato- sphere above a location in Antarctica on September 15, October 15, and November 15, 2000. Key Sepiember IS October 15 November 15 26 £ 24 Key September 15 October 15 November 15 ¢ 20 26 16 0 2 4 6 8 10 12 14 16 18 20 22 E 24 lesser +- -> greater ozone content ozone content 03 partial pressure (mPa ) *mPa - millipascals 20 Figure 2 18 J6 -80 -60 -40 -20 air ternperature (°C) Figuros adapiad from O. Troshichev and l. Gabls, °Effects ol Solar UV Irradiation on Dynamics of Ozone Hole in Antarctica." @2005 by Elsevier, Ltd. Figure I ACT-70G 40 GO ON TO THE NEXT PAGE. 4000000000 .6. According to Figure 2, on Ociober 15, 2000, the 03 partial pressure was zero for all altitudes in which of the following ranges?

Paper 52 · ACT April 2012 · Form 70G · Science Test

Source question 6. Refer to the source image.

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to Figure 2, over the altitude range from 16 km to 26 km, what was the approximate maximum value of the 03 partial pressure on September 15, 2000, and November 15, 2000, respectively. September 15 November 15 2mPa 7mPa 7mPa 20 mPa 20 mPa 2rnP& 20 mPa 7mPa

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to Figure I, of the following altitudes, at which one did the air temperature vary the leasi from Oc'tober 15. 2000, to Novcmbcr 15, 2000 ? ACT.70G 41 GO ON TO THE NEXT PAGE. 40000000004 Passage111 In a chemistry class, the teacher placed a beaker con- taining a clear green liquid on a, heat souice. Over the next 12 min, the volume of thc liquid bteadily dccrcased and the liquid darkened in color. At 12 min, a white solid appeared that floated on top of the remaining liquid. At 16 min, all of the liquid was gone and only the white solid remained. Thc tcacher asked 4 students to provide explanations for what occurred over the 16 min.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Consider the information in the passage about the annual changes in OB content in the .%tratosphere above Antarctica. Based on this information and Figure 2, on October 1, 2000, at an altilude of 18 km.above the location in Antarctica, the 03 partial pressure would tnost likely have been..

Paper 52 · ACT April 2012 · Form 70G · Science Test

Consider the ultraviolet radiation that reached the loca- tion in Antlirctica on September 15, 2000, on Octo- ber 15, 2000, and on November 15, 20(X), after hiiving passed through thc stratosphere. Based on Figure 2, on which of the 3 dates was the inten4ity of the r<ldiation gieatest? averaged ovcr the altitudes fioTn 16 km to 26 km was the least on that date. aged over the altitudes from 16 km to 26 km was the greatest on thilt date. aged over the altitude8 from 16 km to 26 km was the least on thai date. averaged over the altitudes trom 16 kn] to 26 kni was the greatest on that date.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Which of the students would agree that, before heating, the liquid in the beakei was a mixture of substances?

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Student I's eKpldlldlion, why did the volume of thc liquid dccrcase ovcr the first 12 min of heating. Heat caused a liquid to be converted to a gas. Siudenl I The beaker initially contained a solution made by dis- solving a white solid in a pure, green solvent. Over the first 12 min, Ihe solvent evaporated, causing the concentration of the dissolved solid to increase. At 12 min, the volume of solvent had d¢cre<lSed to a point at which the solid was no longer soluble. so it started to exit the solution, At 16 min, all of the solvent had evaporated,

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on the description of the teacher's demonstra- tion, was the density of the white solid that formed at 12 min less than or greater ihan the density of the remaining green liquid? liquid. Student 2 The beaker initially cor]taincd a solution made by dis- solving a white solid in a pure, colorless solvent. Each molecule of the dissolved solid paired wi(h (but did not react with) a solvent molecule to form a green-colored solute-solvent complex (SSC). Over the first 12 min, the solvcnt cvaporated, causing the concentration of the SSC to increase. At 12 min, the volume of solvent had decreased to a poini at which the solid was no longer .801u- ble, so it started to exit the solution. At 16 min. all of the solvent had evaporated.

Paper 52 · ACT April 2012 · Form 70G · Science Test

A ch¢mi&it L.laimed Lhat, in absence oi a solute, NONE of the known liquids are green in color. This claim is inLon.gislént wilh the explanation(s) given by which of the students? Studeni 3 The beaker initially contained ¢1 solution made by dis- solving a green solid in a pure, colorless solvent. Over thc first 12 min, the solvent evapoTated, causing the concentra- tion of the dissolved solid to increase. At 12 min, the high concentration and hedt caused all of the dissolved solid to instantly react with somc of the solvent to form an insolu- ble white solid. At 16 rnin, all of the remaining solvent had evaporated.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Do Student.8 l and 3 differ in their explanations of the 8ource of the liquid's green color? solved solid. No" both students claim that the source is a solvent. I"vS" Student l Claims that the source is a dissolved solid, whereas Student 3 claims Ihai the source is a solvent. whereas Student 3 claim.s that the source ig a dis- solved solid. Student 4 The beaker initially contained a pure, green liquid, Over the first 12 min, the liquid slowly decomposed, but did not evaporate. Ai 12 min, the volume of liquid had decreased to a point at which the product of thc dccompo- sition was no longer soluble. so it 8tarted to exit the solu- tion. At 16 min, all of the green liquid had decomposed, ACT-70G 42 GO ON TO THE NEXT PAGE. 40000000004

Paper 52 · ACT April 2012 · Form 70G · Science Test

Suppose the total mass of the beaker and contents was monitorcd from time - 2 min to titne - 10 min during the heating and that the results were plotted in the graph shown below.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Suppose that after the demonstration, a colorless liquid had been mixed with the solid remaining in the beaker and the liquid then turned green. This observation would have been most consistent with the explanation given by which stlldent? 12 time (rnin) These results would have been n]ost consistent with the explanation given by which student? ACT.70G 43 GO ON TO THE NEXT PAGE. 000000000 Passage IV Scientitits investigated the effect of ultraviolet-B radi- ation (UV-B) on the eggs of 3 species of amphibians: Hyla rcgilla, Rana ca,vcadae, and Bufcj boreas. H. regilla popula- tions are stable, but R. ca.%cadae and B. borea,s' populations are declining. Experimeni 2 Additional B. boreas eggs were collected and divided into 8 groups (GrDUPS 1-8), each containing 30 eggs. Group I was not exposed to UV-B. Groups 2-8 were each exposed to a single dose of UV-B between 82U joules per square meter (JIM ) and 4,100 JIM (see Table l). The per- cent of eggs that were surviving in each group was Iecorded each day for l U days (see Figure 2). Table I UV-B dose (Ilm,) GTOUP Experimént J First, 1,800 newly laid cggs of H. regilla were col- lecLed from a high mountain lake. Next, 150 of the eggs were pl<iced in each of 12 artificial enclosures: 4 that were covered with a filter, FB, that blocked UV-B; 4 that were covered with a filter, FT, that transmittcd UV-B. and 4 that were not covered with any filter. Then, a 8et of these 3 types of enclosures was placed in the lake at eaGh of 4 sites. All Of the above procedures were repcated for the other 2 species. The enclosures were monitored until all the eggs had either hatched or died. The peTcent of total eggs that hatched for each species and type of enclosure is shown in Figure l. 820 1,368 1,915 2,460 2,730 3,550 4,100 Key • Group I + Group 2 + Group 3 -fr Group 4 -Tr Group 5 r Group 6 Group 7 Group 8 Key 11 FB E]FT No filter 100 100 80 90 80 70 60 60 20 50 40 days after UV-B exposure 20 10 Figure 2 coscadae Table 1 and Figure 2 adapt8d from J. Herkovlts, J. L. D'Eramo, and O. Fridman, 'The Effect of UV-B Radiation on Bufo ar8n8rum Embryo8 Survival and Sup8roxide Dismutase Aclivity.. @2006 by MDPI. Figure I 44 GO ON TO THE NEXT PAGE. ACT-70G 40000000004 Experimeni 3 UV-B damages cells by causing cyclobutane pyrimi- dine dimers (CBPDs} to be produced in their DNA. Pho- tolyase is an enzyme found in sotne cells that repairs DNA by removing CBPDS. The phc?tolya5e activity (the late at which CBPDS are rernoved from DNA) present in the eggs of each of the 3 species was recorded (see Figure 3).

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to the results of Experiment 2, for which of the following groups did the peicent of eggs surviving decrease more over the first day after exposuie than over any subsequent day after exposure? Group 5

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to the results of Experiment 2, as the dose of UV-B increased from 820 JIM to 4,100 JIM . how did the percent of B. boreds eggs that were surviving l O days after UV-B exposure vary with dose? ACT.70G 45 GO ON TO THE NEXT PAGE. 0000000004 Passage V In an enclosed space, an aqueous salt solution pro- duces an atmosphere that has a constant relative humidity (RH) Chemists did 3 experirncnts to study this phenome- non using 5 id¢ntical appaiatuses, One of the 5 is shown in Figure l. Experimeni 2 Experirnent I was repeated except that the tempera- ture in each tank was maintained at 30°C (see Table 2). Table 2 airtight tank Aqueous tension (torr) Salt in mixtUTe RH (%) hygromeier Tank controller KOH K,SO, Mgcl, Mg(N03)2 Nacl hatch 96 33 52 75 30 11 17 24 dish containing sali mixture heal exchanger Experimenr 3 Experiment I was repeated except that the tempera- ture in each tank was maintained at 60°C (see Table 3). Figure I A hatch could be opened to place a dish containing a ,Yali mixlure (solid sall in an aqueous solution of the salt) in the airtight tank. A heat exchanger could increase or decrease the temperilture in the tank. A hysrometer mea- sured the RH in the tank and the aqueous tÉnsion (a mea- sure of the tendency of the H O to evaporate from a solution) of the salt mixture in thc tank. The controller regulated the temperature and recorded the hygrorneter reading8. Table 3 Aqueous tension (torr) Salt in mixture RH (%) Tank KOH K,SO, Mgcl, Mg(N03)2 Nacl 96 30 43 75 140 45 64 110 Experiment I On Day I, in preparation for Ihe experiment, a drying agent was placed in each tank. Then, 5 salt mixtures were made by placing dn excess of a salt in H O. The mixtures were stirrcd overnight. Tables adapied from James G. Speight, Lange's Handbook ol Chemistry, 16th ed. 2005 by McGraw-4ill, Inc. By Day 2, the RH iT] each tank was 0.0%. so the drying agent was removed from each tank. Then, 5 dishes. cach containing l of the 5 salt mixtures, were placed in separate tanks. The temperature in each tank was adjusted to a constani IO°C. By Dgly 3, the RH and the aqueous ten- sion had each reached a constant value in each tank (see Table l).

Paper 52 · ACT April 2012 · Form 70G · Science Test

According to the results of Experiment I, eggs of which of the 3 species .4uffeTed less ihan 5% moriality when exposed to UV-B ?

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on the result￿1 of Experimcnt 3, did H. resilla or B, boreas exhibit a gTeater rate of removal of CBPDS ? lower for H. regilla than for B. boreas. regilla, bccause the photolyase activiiy was higher for H. regilla than for B. borea,f. lower for B. boreas than tor H. regilla. higher for B. boreas than for H. regilla.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Following the experiment, the scicntists wanted to cal- culate how many more B. boreas eggs hatched in enclosures with FBS than ill enclosures with no filters. Bas¢d on the results of Experiment I, which of the fol- lowing expressions gives this number? regilla Lg - microgram . C(Lscadae Figure 3 Figures 1 and 3 adapted from Andrew R. Blaustein et al., "UV Repair and Resistanc6 10 Solar UV-B in Amphibian Eggs: A Link to Population Declines?￿ Q1994 by the National Academy of Sciences of the United Stales of Amerlca.

Paper 52 · ACT April 2012 · Form 70G · Science Test

A scientist suggested that the decline in some amphib- ian populations is causcd by an increase in UV-B expo- sure. Experiment I provided which of the following pieces of evidence in support of this hypothesis? For cascadae and B. boreas the percent hatched was: with FTS, whereas for H. regilla thc percent haiched for enclosures with FB.5 was the same a.s for enclosures with FTS. with FTS, whereas for H. regilla the percent haiched for enclosures with FBS was the same as for enclosures with ￿s. with FTS, whereas for H. regilla the percent hatched was greaier for enclosures with FBS than for enclosures with FTS. with FTS, whereas for H. regilla the perccnt hatched was less for enclosures with FBS than for enclosutes with FTS.

Paper 52 · ACT April 2012 · Form 70G · Science Test

When thc rcsults of Experiment 2 were recorded, the moisture content of the air was lowesi in which tank? Table I Aqueous tension (torr) Salt in mixture RH (Y¢) T￿k

Paper 52 · ACT April 2012 · Form 70G · Science Test

Suppose another salt, KCI, had becn tested in Experi. ment 3 and that the RH recorded for KCI was 810/0. The aqueous tension for KCI would most likely havÉ been: KOH K,SO, Mgcl, Mg(N03)2 Nacl 13 98 34 57 76 ACT-70G 46 GO ON TO THE NEXT PAGE. 40000000004

Paper 52 · ACT April 2012 · Form 70G · Science Test

A student predicted that for a given salt in Experi- ments 1-3, RH would always decrease as teTnperature increased. This prediction wab consistcnt with the results for which, if any, of the salts listed below? I. Mgcl,

Paper 52 · ACT April 2012 · Form 70G · Science Test

A student predicted that undei any of the conditions used in Experiments 1-3, if the RH in any 2 tanks was the same, then thc aqueous tensions of Ihe salt mix- lures in the tanks would be the same. Do the result.s of Experiments 2 and 3 support this claim? to the RH iii Tank 3 in Experiment 3, and the aque- ous tensions were the same. to the RH in Tank 5 in Experiment 3, Lind the aque- ous tensions were the same. the RH in Tank 3 in Experiment J, but the aqueous tensions were different. the RH in Tank 5 in Experiment 3, but the aqueous tensions were dit-ferent.

Paper 52 · ACT April 2012 · Form 70G · Science Test

What was the purpose of the first procedure that wag carried out on Day l ? in the tanks constant ture in each tank was constant

Paper 52 · ACT April 2012 · Form 70G · Science Test

In Experiments 1-3. was RH an independent variable or a dependent variable? directly by the chemists. the chemists. directly by the chemists. the chemists. ACT-70G 47 GO ON TO THE NEXT PAGE. 40000000004 Passage Vl The pressure, P , exerted by a liquid varies with Ihe depth, D, below the surface of the liquid and with the liquid's density, p. If a tank of liquid is opcn to the atmo- sphere, the total pressure, P at D equals PL at D plus the atmospheric pressure, P 500 y 400 Table I lists p, in kilograms per cubic meter (kglm ), for 4 liquids at 25°C. 200 Table I 100 Liquid (kglm ) 10 20 30 D(m) Carbon tetrachloride Ethanol Ethylene glycol Water 1,580 786 997 Figure 2 Figure I shows. for D - 10 m, a graph of PL (in kilo- pascals, kPa) versus p (I kPa 10 Pa - 10 newtonslm ). Figure 2 shows a graph of P versus D and a graph of P versus D for 25°C water in a tank tbat was open to the attnosphere on a particular day. 150 11 100

Paper 52 · ACT April 2012 · Form 70G · Science Test

What is the correct ranking of the liquids listed in Tablc I, from the liquid with the least denslty at 25°C to the liquid wilh the greatest density at 25°C ? water ethanol glycol 50 6(K) 81N) 1.000 1,200 1.400 p (k￿rn. ) Figure I ACT-70G 48 GO ON TO THE NEXT PAGE. 40000000004

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Table l and Figure.1, compared to PL at 10 m in 25°C ethanol, PL at D = 10 m in 25°C carbon tetrachloride will be approximately:

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Table l. the mass of 3 m of cthylene glycol at 25°C would be closest to which of the following values?

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Figure 2, the relationship between Pi. (in kPa) and D (in m) for the water in the tank is best rep- resented by which of the following equations? as great. as great. J9.6xD

Paper 52 · ACT April 2012 · Form 70G · Science Test

Based on Figure 2, on the particular day, 20 m below the Surface of the water in the open lank, PL plus P was closest to which of the following values? ACT-70G 49 GO ON TO THE NEXT PAGE. 40000000004 Passage Vll In some locations, drainage water from agricultural areas contains selenium (Se), a substance that can be harm- ful to wildlife. Se can be removed fiom water by plant uptake or by adsorption onto soil and organic particles. Three studies wcrc done to examine Se removal by human- made wetlands, Study 3 In December 2000, sarnples of each of the following materials were collected frotn several locations in each wetLand= fallen plant litter (dead but not decayed plant matter), organic detritus (decayed organic matter on top of the soil). and the top 5 cm of the S'oil. The samples of each material were analyzed for Se, and their average Se concentration, in milligram.s per kilogram dry weight (mglkg dw), was determined (see Figure 2). Study I Five open-water wetlands (Wetlands 1-5), each 15 m x 76 m in area, were constructed at a location in May 1997. At th&t time, 4 of the wetlands were planted with the same densiiy of l or 2 types of wetland plants. From January 1998 thiough December 2000, drainage water con- taining an average Se concentration of 22 micrograms per liter (HglL) was continuously fed into each weiland at a flow rate of 300 m Iday. The average residence tI￿e (RT, how long a volume of water remained in the wetland) was deteTJnined for each wetland (See Table l). Key plant litier organic detritus top 5 cm of soil 20 18 16 14 10 Table I Type(s) of plants in wetland bulrush none cordgrass bulrush and cordgrass attail Average RT (days) Wetland 11 Wetland 10 19 13 Figure 2 Tab18 and figures adapied from S. Gao et al.. 'Selenium Removal and Mass Balance in a Gonstrucled Flow-Through Wet18nd System.. @2003 by the American Soci81y of Agronomy, the Crop Science Society of America, and the Soil Science Society of America. Study 2 Every week from January 1998 thiough December 2000, the outflow water from cach wetland was sampled and analyzed for Se. The average annual Se concentration of the outflow was determined for each year (see Figure l )- Key 111998 E] 1999 21M)O 16 14

Paper 52 · ACT April 2012 · Form 70G · Science Test

Figure 2 indicates that the average Se concentration of organic detrilus, averaged across all 5 wetlands, was closest to which of the tollowing. 2 Tng/kg dw 5 mg/kg dw 8 mglkg dw

Paper 52 · ACT April 2012 · Form 70G · Science Test

In the studics. which wetland served as the control for the effect of plants on Se removal? 10 Wetland Figure I ACT.7 50 GO ON TO THE NEXT PAGE. 40000000004

Paper 52 · ACT April 2012 · Form 70G · Science Test

Is the statement "The outflow having the least average annual Se concentration for 1999 was from the w¢tland having the greatest average RT" supported by the results of Studies l and 2 9 the outflow from Wctland 4 had the least aveiage annual Se concentration for 1999. the outflow from Wetland 5 had the leasi average annuaj Se concentration for 1999. outflow from Wetland 4 did not have the least average annual Se concentTation for 1999. outflow from Wetland 5 did not have the least average annual Se conceniration for 1999.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Water having an S¢ concentration of 5 HglL or greater Is considered harmful to wetland wildlife. If Study 2 had been continued through December 2001, which wctland would rnost likely have produced outflow in 2001 having an averagc annual Se concentration no longer considered harmful to wetland wildlifeg END OF TEST 4 STOP! DO NOT RETURN TO ANY OTHER TEST. ACT.70G 51 Explanation of Procedures Used to Obtaln Scale Scores from Raw Scores On each of the four test5 on which you marked any responses, the total number of correct responses yields a raw score. Use the table below to convert your raw scores to scale scores. For each test, locate and circle your raw score or the range of raw scores that includes It in the tsble below. Then, read across to eithor outslde column ol the table and circle the scale score that corresponds to that raw score. As you determine your scale scores, enter them in the blanks provided on iho right. Tho highest posslble scale score lor each test is

Paper 52 · ACT April 2012 · Form 70G · Science Test

Why was the unit of me2surement for Se concentration different in Studies2and3 ? In Siudy2, the Se concentration.. ol a liquid was being determined, whereas in Study 3, the Se concentration of each of several solids was being determined. of each of several solids was being determined, whereas in Study 3, the Se concentration of a liquid was being determiT]cd. of a liquid was being determined, whereas in Study 3, the Se concentration of a different liquid was being determined. of a solid was bcing determined. whereas in Study 3. the Se concentration of a dift-ercnt solid was being determined.

Paper 52 · ACT April 2012 · Form 70G · Science Test

Do the results of Study 3 for Wetlands 1, 3, and 4 indi- cate that in these wetlands, plant uptake reduced thc Se concentration of the water more than did adsorption onto soil particles? tion of the plant litter was greater than the average Se concentration of the top 5 cm of soil. tion of the top 5 CTn of soil was greater than the average Se concentration of the plant litter. tion of the plani litter was greater than the average Se concentration of the top 5 cm of soil. tion of the top 5 cm of soil was greater than the average Se concentration of the plant litter.