ACT Past Papers with Answers

Paper 78 · ACT April 2005 · Form 60E · Science Test

If Scientist l is Corr￿¢t, exposing its sail to a strong M'ind would have whicb of the following effects OD a DimeTI"odort"s body ternperature? Exposing its sail to a lllind at a ternperature less than the body temperature of Dinjetrodon would: sarm ihe sail and louier the body iemperature. wann the sail End raise the body iemperarure. remove heAt from the sail and lower the body iern- perature. remove heal Irom the sail and raise the bod)I iern- perature. Grooves on the Rail's spiiies held large blood vessels. Regulating ihe blood flow throuoh these vessels during the heat of the day allowed the reptile io radiate heat awa), fvom its boov and prevenl oiierheaiino Four other cold-blooded reptilc bpecies from tbis same titne and 'climate also had bony projections or sails on their back. Toda),, elephanis I'egulaie their body iemperaiuTe b}, flapping their18rue ears. ACT.eO GO ON TO THE NEXT PAGE. 40000000004

Paper 78 · ACT April 2005 · Form 60E · Science Test

Accoiding. to ScieDtist 2, rrLalc DimetrDdons would control the blood supply to their sails in older to: increase or decreas& the spines, width. reduce their body temper3tllre. change tbe sails, coloi or pattern. iaise or lower their sails:

Paper 78 · ACT April 2005 · Form 60E · Science Test

Both scientists would most likely aoree with which. of the. following statements about Dimelrodons and . modern animals? some modern animals. and any modern animal<. indirect dcscendantg of DimeirodorLS. ' like Dimetrodons. direction of late. afternoon sun direction of late afternoon sun sail dyiection of late afternoon sun diFeCtiop. of late afternoon sun . .5. According to Scientist l. a cold-blooded, carnivoIous reptile without a sail would have cornpared to a Dimet- rodon of the same size in which of the following ays?. This reptile without a sail would have: ieaclied tbe activity. tempera.ttire more slowly than did Dtmetro'don. rcached thc activity te.mperature more quickly than did Dimetrodon. sail sail AC7-6DE 39 GO ON T.0 THE NEXT PAGE. 40000000004 Passage 11 Experiment 3 The procedurc from EKperiment I was repeated at a constant temperaiure of 2'5°C and various concentrations of H C O . The results shown in Table 3. Thc rate of a chemical. reaction can be measured as the change in the concentration of its products over a period of time. The following experiments were peiforrned to investigate factors that iufluence the rate at which potas- slum permanganate {KMnO ) rcacts. with ox&lic acid (H C O ) to forni Mn and other products, Table 3 Concentiation of Reaction tirne {scc) Trial HCO (M). xperiment I A 4.0 ML sample of 0.1 M (moles/liter) aqueous Kmno which was purple in color, was tneasured with a clean graduated cylinder and poured into a test tube. A

Paper 78 · ACT April 2005 · Form 60E · Science Test

C

Paper 78 · ACT April 2005 · Form 60E · Science Test

Both scientists would most likely agree with which of the following. statements about DimÉ£rodons and their sails ? Dimetrodons were able to: Taise and lower their sails at will. she(1 and iegiow their sails peIiodically, control Ihe blood supply to theii sails. I¢'gulatc body tempeIature without th¢ir sails.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on the information in Scientist I's vieTrvpoint, which of the following figures best represents how a DimEtrodon would orient its sail with respect to the sun in ordcr to minimize heating during late afternoon?

Paper 78 · ACT April 2005 · Form 60E · Science Test

In Experiment I,. as the reaction tempe13tuie incieased, the time until th¢ purple color disappeared.. Temained the same. increased only. increased, therL d¢creased. Experiment 2 The proced&e frorn Experiment I was repeated.in every way except that 0.1 mg of manganous sulfate (MnSO4), a catalyst. was added to each tesl tube contaiRing Kmno bcfore the H2C204 was added. Catalysts sub- stances that increase the rate of reactions without bein used up. The results are shown in Table 2.

Paper 78 · ACT April 2005 · Form 60E · Science Test

If the procedure described in Experiment 2 was repeated and a reaction tiTne of 6 sec was mtasured: the ternperature of the reaction was most likely: Table 2

Paper 78 · ACT April 2005 · Form 60E · Science Test

00 ML of which of the following aqueous solutions would be the greatest?

Paper 78 · ACT April 2005 · Form 60E · Science Test

Each of th¢ followiiig factors was investigated in the experirnents EXCEPT: adding 2 catalyst to the reaction mixture. changing the reaction solvellt. vaiying thc Tcaction Icmperature. chang3ng thc concentratioTr of a reactant.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Source question 12. Experiment I, rnixing an H C. O solution at 45°C with a ICMnO solution at 40°C. Based orA the results of Experirncnt l. the reaetion time was most likely: ACT-"8OE 41. GO ON TO THE NEXT PAGE. 40000030004 Passage 111 Table ry lists the diam.eter and surface area of 5 types of spherical ova (egg cells). As a IiviDg cell's surface Grea-to-volume rafio (SIV) increases, so does the cell, s ability to exchanoe substances Witli its environment. Table 2 To model this exchange process: different-sized cubes of (yelatin were immersed in a dyc for I xuinule. Table I lists the edge length. surface area, volume, SIV, and per- cent volume of gelatin that was dyed. Diameter jmm) Surface area Type Sea urchin Human Hummingbird Hen Ostrich '0.03 100 2,000 30,000 Table I 25 100 Edge lengih (mm) Surface area Percent volume dyed 100 100 84 43 Volume slv Table 2 adapted Irorn Norman K..Wessells and Janel L. Hopson, Eiology. Q1988 by Random House. Irr. 24 96 384 1,536 512 4,096 16 Fioure I shows the sr< of certain rectsngular solids and spheres. rectangular solid sphere 16 length of rectantrular solid OT diarneter of sphere (mrn) (Nole: For each reclangulaT solid, ￿Qdth = height - I mn].) Figure I Figure 2 shows the volume of ceriain Tect2ngulaT solids and spheres as a function of surface area.

Paper 78 · ACT April 2005 · Form 60E · Science Test

A student repeating Trial 9 unknowingly used & gradu- ated cylilldeT thal already contained 1.0 of H O to measure the H C Q solution,. Based on the results of Experiment 3,. the reactiofj tsme that she mcasuicd was inost likely- 625 sec. 837 sec.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on ihe informaiion in Table I, a cube-shaped cell ￿'1th which of the following edge lengths will have the ￿reatest STh" ? 16 surface area (mm ) (Noie: FOT each rectanoular solid, width = height - I mro.) Figure ? 32 Acf.6DE GO ON TO THE NEXT PAGE. 40000000004 .16. Which of the foLlowiDg best describes why the units for the Stv in Figure l are rnm ? face area are mm . surface area arc volume are mjn . foi volume arc .

Paper 78 · ACT April 2005 · Form 60E · Science Test

A

Paper 78 · ACT April 2005 · Form 60E · Science Test

J

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on the information i]x Figure I, a spherical cell with a diameter of 6 mm will bave an SIV closest to which of the following values? AGT.60E 43 GO ON TO THE NEXT PAGE. 40000000004 ..Passage IV Experimeni 3 A 90 8 sarnplc of H O (fT¢czing point - O°C) and 10 g of C H O (freezing point - _l L.5°C) were'placttd in a cup containing a thermometer. The mixtUTe.was stirred as it was cooled in a low-temperature b2th. The temperature at which ice crysLals first begao to appear was recorded as freeLiDg point. The proceduTC was repeated with differcrit amollnls of H O and C H O (see Table l). Soffje studcnls were intcrGsted in why antifreeze is uiixcd with ihe H O in a car.s Tadiator. They knew Ihal whcn a substance is dissolved in H O, tbe boiling poiDts are eleTrated and the freezing points ale lowered relative to H O. Trev peiforrncd th¢ following experiments to investi- 83tc thc effects of the addition of eihylene glycol (C H O ), the active ingredieni in most types of anlifreeze, 10.H O. TabLc I M&ssofCHO (g) MassofHO (g) Frcezino .point (°C) Experiment I Six solutions of various concentrations of C2H602 in H O w¢re prepared. The mass of l 0.00 JJL of each solulion was measured, aD.d the dellsily of each solution was calcu- lated using tbe following foimul2'. 10 20 30 40 50 60 90 80 70 60 50 40

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based (Sn the information in Table I, if a cube-shaped plant cell had an edge length of 0.5 mm, it would have an SIV of: 6mm

Paper 78 · ACT April 2005 · Form 60E · Science Test

If Experiment 2 were repeated with an aqlleous solu- tion containing 80% C2H602 by mass, the boiLins point of the solution would mosi l-thely be: 2￿ 190 180 160 150 140 130 120 110 ICK)

Paper 78 · ACT April 2005 · Form 60E · Science Test

Wher¢ the students live, the low¢st temperature during the past year was -31°C. Based on the Iesults of Experiment 3, which of the following percents, b! m'ass, of C21402 in H O would have been necessarv to bc suIe thai the mixtures in car radiators in this arca did not freeze? 0 10 20 30 40. 50 60 70.80 90 ICK) % C2F402 (by mass) in H O Figute I Arr.￿E.. GO ON TO THE NEXT PAGE. 40000000004

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on the results of Experiment I, the mass of

Paper 78 · ACT April 2005 · Form 60E · Science Test

A student repeating Expériment 3 placed an aqueous mixture containing 6590 C2H602 in ihe loiv-tempeiature bath. She did not obseive'the foimatkon of any crystals. Ivhich of tbe following statements best explains this observation? exactly the same as the mixture's freezing point. higher than the rnixture's freezing point. lower than the mixiure's freezing point. frcczing DOlIit.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based. on the results.of Experiment 2, why would it be beLter to use a n]iKture of antifreeze and H O ratber than purc H O in a car radiator during hot wcathci. The mixtllre has a:

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on the passage and the icsults of Experiment 2. which of the following types of water would most likely have the lowest boiling point? ACT-60E 45 GO ON TO THE NEXT PAGE. 40000000004 Passage V Experimeni 2 .The procedure described in Experimenl I was repeated using a coppei wire with a diaJneter of 1.4 tnm. The results are shown in Table 2. Heat conduction Is a process by which heat LS trans- ferred from a region at a higher tempeTature Lo a region at a lower temperatuie. Two regions that are in ihermal equilib- rium with each other are at the same temperatuie. No lieat is Iransfcrred between regions Jn thermal equilibrium with . each other. Table 2 A student studied the ielationship belween ilie length and diamctcr of a copper wiic connecting 2 metallic blocks and the rate of heat conduction between thc blocks. Temperature (°C),of Block A aftei- Temper3tuIe (°C) of Block B after- Lengih of wire (cm) Imin 2min Imin 2 Jnin 3min 10 20 30 61 79 85 45 65 75 40 53 66 34 17 12 45 25 16 40 35 20 Experimenr I A small alllminuJn block,. A, was heated to IOO°C in boiling watcr, and an identical aluminum block, B., was cooled to O°C in ice water. Both blocks were immediately placed on an insulaling'surface (a surface that does not conduct heat well) and connected by 2 given leDgth of mm diameter copper wire initially at rootn tempeIature so that the wire would conduct heat from Block A lo Block ￿ (see Figure l). A:Left B:Right blocks lite insulaiing surface Figure I

Paper 78 · ACT April 2005 · Form 60E · Science Test

The best way to tegc the hypoLhesis that the rate of heat conduction depends on the type of wile material llsed in the experiments would bc to repeat the experiments using: silver wires.and aluminum wires differincr in size fiom the copper wires. silver wires and aluminurn wires haviDlJ the sarne sizes as the copper wiFes. copper wires each having a different diameter. copper wires each havinu a different length. The temperature of each block was.tneasured at regular lime intervals for 3. rninutes. The same procedure was.done with different lengths of I mm diameter copper wire. The results are shown in TabIe l. Table I Length of wire (cm) Temperature (°C) of Block A after: Temperature (°C) of Block B after:

Paper 78 · ACT April 2005 · Form 60E · Science Test

Durino Experiments l and 2, the 2 blocks reached thermal equilibriutn when which of the followino copper wires was used? I tnin 2 tnin 3min Imin 2miu 3min 10 20 30 79 88 91 66 80 85 54 72 78 18 25 15 10 31 19 14 ACT-6DE 46 GO ON TO THE NEXT PAGE. 40000000004

Paper 78 · ACT April 2005 · Form 60E · Science Test

B ased.on ExperimerAto l and 2. which of thc following graphs best represents the 'relationship .between the leDgth of a copper wire of a given diameter arid the tcrnpcraturc of.Block A at a givcn timc?

Paper 78 · ACT April 2005 · Form 60E · Science Test

As themal.conductivity decrcases, tbe ability to con- duct heat decreases. Brass has a thermal conductivity one-third that of copIier. If, in any of the experiments, a copper wire v/ere replaced with a brass wire of th.e same length and diarnetcr, which of the following out- comes would be most likcly. copper wire was used. a copper wire was used. a copper wire was used. copper wire was used. length of wire

Paper 78 · ACT April 2005 · Form 60E · Science Test

In each of the'2 experirnents, the araount of heat lost by Block A was greater than the amount of heat gained by Block B. The most piobable expIanaiion for this incquality is that: the copper wire lost heat to Block A. .the ali lost heat to Block B. leugth of w}ie leD.(rth of wire

Paper 78 · ACT April 2005 · Form 60E · Science Test

Supposc, afÈer 4 minutcs, thc tcnperaturc of Block A was 64°C and that of Block B was 23"C. According to the results of the eXperi￿ents, which of the following copper wircs was tuost likely beillg used to connect the bIocks? "F. A I mm diameter wire, 10 crn lorjg . lenoth of wire Af.6 47 GO ON TO THE NEXT PAGE. 40000000004 Passage Vl Ali al its.dew point.remperature (or dew poinl) is satu- iated with water vapor. Air temperature usually decreases with increasiIig. altitude. When 2ir cools to its dew point, 'the water vapor in tbE air can begin Éo condcn%c and form clouds. ICKI 98 City C -87 80 76 65 51 49 47 45 averdge doud-b2se 3]tiNde Air tcmpeiatures and dew points were raeasured everv 600 ￿ fjrO￿ the surface (O m) to an altitude of 3,000 m at 4 cities (A-D). Data,.includirig ihe zltitudc of tbc cloud base over e2ch city, weie tiken at 2 p.m. on every SUmmeT day that clouds wcrt prcsent. Figures 1-4 show the average ali tCtnperati￿cs, the avera£e dew points, and Lhe average cloud-base altitudes at each city. 43 30 1,200 I,8 2,4(N) 3,000 (surface) aIti￿de (m) Figur6 3 Citv D Key air tcmpcratur¢ 66. 80 77 70 79 .+- dew point 57 63 70 56 63 50 avcrdgc clood-b&se 2Jutude 45 air. te[nwa￿le 48 dcw point 34 CityA 1,2(K) 1,8(K) 2,4C (surface) a]titllde (m) 80 77 55 59 57 48 55 41 avcr&sc cloud-base 2ltitJJde 34 41 34

Paper 78 · ACT April 2005 · Form 60E · Science Test

B

Paper 78 · ACT April 2005 · Form 60E · Science Test

A ceilometgr bounces a light beam off the base of a . clolld layer and m¢asures how Iono it takes the light to makc the trip up and back. The scientists who made thc measurements plotted in Figures 1-.4 most likely used the ceilometei to. determine which of .the followino data? layers at Cities A-D cloud layers at Cities A-D layers at Cities A-D Cities A-D 34: The table below shows the average July air ternpera- tures and dew points at O m altitude for Miami, Florida,. and for Phoenix, Arizona. Aiierage air temperature Average dew point City Mia￿] Phoenix (°F) 85. 95 (°F) 70 36 B2sed on this information and tbe data in Figures 1-4, which of these 2 cities, on average, would have lower cloud bases in July? peiature than Miami. averagR air temperature alld the average dew point is .arger than in Mi&lli. ' perature than Pboeuix, average ur temperature and the aveiaEC dew point is smaller than in Phoenix.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Assume tbat thc cloud layer at City C extends from an altitude of 3,000 m up to an altitude of 4.000 m. Based on this assumption and the observed trends w)it4ir. cloud layers for the 4 cities, which of the following would be the. best appioximation of the ali tellLperatuie and dew. point in the cloud layer at an altitude of 3,600 m over City C ? AiT temperature 26°F 36°F 38°F 45°F

Paper 78 · ACT April 2005 · Form 60E · Science Test

G

Paper 78 · ACT April 2005 · Form 60E · Science Test

A certaiu ckty reported that the aiT lemperature and the dew point at. O m altitude tueasured at 8 A.ii. on a !ven da)y wert both 40°F. Givcn this information and the data provided, one could bc most certain that clouds were Present at which of the following altitudes at that city at 8 A.M. Oll tbat day . Dew point 36°F 36°F 45"F 45"F 600m ACT.60E 49 GO ON TO THE NEXT PAGE. 40000000004 Passage Vll. The amount of 02 pTesent in blood and tigsues can be n]easurcd. in mm Hg, as the parlial préssure of O? (Po,). Tbe perceni saturation of Hb is the percent of hemoglobin in tbe blood that is bound wiith O Figllrc I shows tbe rel2- tionship bctween percent salur3tion of Hb and Po, at normal body conditions. Figure 3 shows the relationship between percent saturation of Hb and Po, at difterent blood temperatures. io'c 90 20°C 80 70 43°C ILK) 50 40 80 70 20 io 0 10 20 30 40 50 60 7Q 80 90 1 Po, (rnrn Hg) 20 Figure 3 Figures adapted from Robert Carola, John P, Harley, and Chorlos R. Noback, Hurrisn Anatorny 2nd Physiology. 1990 by McCraw- hill,, Inc. io 0 10 20 30 40 50 60. 70 80 90 100 P,, (mm Hg) Figure I Figure 2 shows the. relationship between pcicent saturation of Hb and Po, at different pHs. The PH of blood is'affeclcd by thc partial prcssurc of CO (Pco,). Ico higb blocd PH (7.6) Oow Pco,) normal blood PH (7,4) (norn)al Pco ) ' low bl(xxl PH (7.2) (high Pc4) 20

Paper 78 · ACT April 2005 · Form 60E · Science Test

According to Figure I, the greatest change in the peT- cent satiirauon of Hb occurs within which of the fol- lowing partial piesfurc ranges? OmmHgtolOmmHg 20 80 l(x) P,, (nlln Hg) Figure 2 ACT-60E 50 GO ON TO THE NEXT PAGE. 40000000004

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based on Figures 2 and 3, if blood has a'Po, of 40 Hg, the amount of oxygen bound to Hb would be greatest at which of the following sets Oi collditioxjs?

Paper 78 · ACT April 2005 · Form 60E · Science Test

A researcher has claimed that the ability of Hb to bind with O at a given Po, will decrease as temperature is increased.. Do the data in Figure 3 support his claim? ration of Hb increased. ratioll of Hb decreased. uration of Hb increased., 1ITation of Hb.decreased.

Paper 78 · ACT April 2005 · Form 60E · Science Test

Which of the following tables represents the 2ssump- tions about temperatllre and pH th'at would have to bc made to propcrly interpret thc data in Figure8 1-3 ? Factors held constant PH on]y temperature only tenweTatiire and pH Ficxure 2 Figure 3 Factors held constant Figure I Figurc 2 Figure 3 PH only ternpcratuie and pH temperature only Factors held constant Figurc I FIg￿e 2 Figure 3 t¢mpeTaturc and pH pH only lemperature only Factors held CODStant Figure I Figure 2 Figure 3 temperature and pH temperature only pH only

Paper 78 · ACT April 2005 · Form 60E · Science Test

Based" on thc data in Figurc 2. which of the followin(y statements best explains why Pco, affects the PH of blood? When CO dissolves in blood, it: absorbs acids. re&cts with O to form Hb. END OF TEST 4 STOP! DO NOT RETURN TO ANY OTHER TEST. AcT-￿E 51 Fom 60E (April 2005) Parachuting Math Readin Science l)D