ACT Past Papers with Answers

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on Student 3's hypothesis, a wood mouse would be least likely to be captured by a predator during the: new moon at a foraging site with.shelter. new nioon at a foraging site without shelter. 50 0 10 20 30 40 50 60 70 80 90 1(K) moonlight brightness (%) Figure adapted Irom Ramon P6rea et al., °Moonllght and Shel- ler Cause Dllferential Se8d Selection and Removal by Rodenis.. 011 by The Association ior the Stutjy of Animal Behaviour. These results are consistent with the hypothesis or hypotheses of which of the studcnts?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consider the results of the experiment, during the new moon and during the full moon. for the site without shelter. Are these results consistent with the hypothesis of Stud¢nt l ? than during the full moon. than during the full moon. than during the full moon. than during the full moon.

Paper 27 · ACT April 2018 · Form A09 · Science Test

Before the experiment, which student would most likely have predicted that the number of wood rnouse visits would be approximately the same for all the con- ditions that were tested? ACT-AOg 39 GO ON YO THE NEXT PAGE. 40000000004 Pa8sage11 Resistivity is the tendency of a material to oppose the tlow of an electric current, whereas conductivity is the abil- ity of a material to carry an electric current. Table I lists, for each of 12 metals at the same temperature, the density (in grams per cubic centirneter, glcm ), resistivity (in ohm meters, Q.m), and conductivity (in siemens per meter, Slm). Figure I shows, for 3 of these metals, how resistivity varies with temperature (in kelvRns. K). Key calciutn aluminum gold Table I Density (glcm,) Resistivity (x IO" Q.m) Conductivity (x 10 SIM) Metal Aluminum Beryllium Calcium Copper Gold Iron Lithium Magnesium Potassium Silver Sodium Tungsten 200 , 31X) 500 temperature (K) 7(X) Figure I AGT.A09 40 GO ON TO THE NEXT PAGE. 40000000004 According to Figure I, at a temperature of 600 K, which of calcium, aluminum, and gold has(have) a resistivity greater than 7 x 10- Q.m ?

Paper 27 · ACT April 2018 · Form A09 · Science Test

The A508 of the solution formed was measured with colorimeter. Table I shows. for each of the 6solutions formed (Solutions 1-6), the volume of stock solution used. the 2+ Fe concentration, and the A 508.

Paper 27 · ACT April 2018 · Form A09 · Science Test

The results of the experiment are most consistent with the hypothesis of which student?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Which of the following questions was addressed by each of the hypotheses but cannot be directly answered by the results of the experiment? the chance (hat a wood tnouse will be captured by a predator? the chance that a wood mouse will construct a nest at a foraging siie? mice during a new moon than during a full moon? visits from wood mice than does a foraging site without shelter?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Source question 8. Refer to the source image.

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on Table l. of the following 4 metals, which has the greatest ability to carry electric current?

Paper 27 · ACT April 2018 · Form A09 · Science Test

According to Figure l. approximately how many times as great is the resistivity of aluminum at 600 K than at 320K?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Suppose that a certain metal has a resistivity of

Paper 27 · ACT April 2018 · Form A09 · Science Test

When choosing a suitable metal for use in overhead electrical cables, engineers prefer a metal for which the expression (density) x (resistivity) has as small a value as possible, Based on Table l. which of the fol- lowing metals would be most suitable for use in an overhead cable?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on Figure I, the resistivities of the metals listed in Table I were most likely measured at a temperature closest to which of the following. ACT.AO 41 GO ON TO THE NEXT PAGE. 40000000004 Pa88age 111 Table 2 When Moina micrura (microscopic aquatic crus- taceans) are exposed to unfavorable environmental condi- tions, they produce ephippia (specialized eggs that each contain a dormant embryo). The embryos remain dorniant until the ephippia are exposed to favorable environmental conditions that cause the ephippia to hatch. Two experi- ments examined how pH and light intensity affect the hatching of M. micrura ephippia. Light intensity (lux) Group 300 650 850 1,300 Experiment I Each of 15 identical beakers received 50 ML of water and 120 freshly laid M. micrura ephippia. The beakers were then equally divided into 5 groups (Groups L-P). For each group of beakers, the water was maintained at l of 5 different pH values (see Table l). At the end of 7 days. the average number of ephippia hatched in each group was determined as in Experiment I (see Figure 2). 80 70 Table I Group pH 10 Group Each beaker was then incubated at 27°C and received 12 hr of light per day at a light intensity of 650 lux. At the end of 7 days, the number of ephippia that had hatched in each beaker was counted, and the average number of ¢phip- pia hatched in each group was calculated (see Figure l). Figure 2 Figur88 adapt8d from N. E. T. Rolas, M. A. Marins, and O. Rocha, "The Effect of AblotSG Factors on the Hatching of Moina miGrura Kurz, 1874 (Crustacea: Cladocera) Ephipplal Eggs.. 001 by the International Instltut8 of Ecology. 80 70

Paper 27 · ACT April 2018 · Form A09 · Science Test

According to the results of Experiment 2. arnong the 5 groups tested. as the light intensity increased, the average number of ephippia hatched: increased only. increa5¢d and then d¢¢reas¢d. 10 Group Figure I

Paper 27 · ACT April 2018 · Form A09 · Science Test

Suppose that a scientist wants to develop an artificial system for hatching M. micrura ephippia in a labora- tory environment. Based on the results of Experi- ment l. which of the PH values tested would most likely maximize the chances of hatching M. micrura ephippia in this system? Experiment 2 Each of 20 identical b¢akcrs rcccivcd 50 ML of water and 120 freshly laid M. micrura ephippia. The beakers were then equally divided into 5 groups (Groups Q-U). Each beaker was incubated at 25°C, and the water in cach beaker was maintained at a pH of 7.0. Group Q was kept in the dark, and each of Groups R-U received 12 hr of light per day at l of 4 different light intensities (see Table 2). AGT-A09 42 GO ON TO THE NEXT PAGE. 40000000004

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consider the units of measurement "ML" and -lux" in Experiment 2. Which of the following phrases best dcscribes the'quantities represented by those units? lux duration of light exposure light intensity duration of light exposure light intensity

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consider the statement "The number of ephippia that hatched. on average, was greater for the ephippia kept in the dark than it was for the ephippia exposed to light." Do the results of Experiment 2 support this statement? Group R, Group S, Group T, or Group U was greater than the average number of ephippia hatched in Group Q. Yes: the average number of ephippia hatched in Group Q, Group. R, tsroup S. or Group T was greater than the average number of ephippia hatched in Group U. Group R, Group S, GroupT, or Group U was greater than the average number of ¢phippia hatched in Group Q. Group Q, Group R. Group S, or Group T was greater than the average number of ephippia hatched in Group U.

Paper 27 · ACT April 2018 · Form A09 · Science Test

Which of the following pieces of equipment was most likely used to collect the data that were averaged to produce Figures l and 2 9 mass of water mass of water volume of water volume of water

Paper 27 · ACT April 2018 · Form A09 · Science Test

In Experiment I, the total length of time a group of b¢akers was exposed to light was: 12 hr. 24 hr. 84 hr.

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consider the claim "The length of time that the beakers in a group were incubated affected the average number of ephippia hatched in the group., Can this claim be evaluated on the basis of the results of the 2 experiments? each group. the groups. group. the groups. ACT-A09 43 GO ON TO THE NEXT PAGE. 40000000004 Passage IV Figure 3 shows how BP varies with atmospheric pres- sure for 3 other compounds: ethanol. methanol, and methyl acetats. The unit of pressure is kPa. Atmospheres (atm), torr, and kilopascals (kPa) are eommon units of pressure. Figure I can be used to convert between torr and kPa. A pressure of l atm is indicated in Figure l. 90 ethanol. 160 80 methanol 140 70 120 methyl acetate 50 80 90 i(x) atmospheric pressure (kPa) 110 120 130 140 80 700 800 9￿ I,(tJo I,100 I,200 pressure (torr) Fisure 3 Figure I

Paper 27 · ACT April 2018 · Form A09 · Science Test

According to Figure 2, which of the following graphs best shows the BPS of acetaldehyde, acetone, and pen- tane at 850 torr? Figure 2 shows how boiling point (BP) varies with atmospheric pressure for 3 compounds: acetaldehyde. ace- tone, and pentane. The unit of pressure is torr. 60 70 30 30 60 50 acetone r4 30 20 acetaldehyiie 850 900 950 1,(x)o 30 30 10 700 750 8(KI atmospheric pressure (torr) Figure 2 ACT-AOg 44 GO ON TO THE NEXT PAGE. 40000000004

Paper 27 · ACT April 2018 · Form A09 · Science Test

According to Figure 3, at 110 kPa, the BP of methyl acetate is approximately how much lower than or higher than the BP of ethanol?

Paper 27 · ACT April 2018 · Form A09 · Science Test

According to Figure 2. the BP of pentane at 700 torr is closest to the BP of acetaldehyde at which of the fol- lowing atmospheric pressures? 700 torr 800 torr 900 torr

Paper 27 · ACT April 2018 · Form A09 · Science Test

A compound's siandard boiling point is the tempera- ture at which the compound boils when the atmo- spheric pressure is l atm.'Based on Figures l and 2, the standard boiling point of pentane is approximately:

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on Figure l. a pressure of 2 atm would corr¢- spond to a pressure in torr that is:

Paper 27 · ACT April 2018 · Form A09 · Science Test

Suppose a sample of methanol is in a chamber main- tained at 60"C and 110 kPa. Based on Figure 3, if the temperature is kept constant. which of the following changes in the pressure will cause the sarnple to boil? AGT.A09 45 GO ON TO THE NEXT PAGE. 40000000004 Pa88age V Experiment 2 Each of Brands A-D was analyzed by crushing I tablet, dissolving the powder in H O to form a l 00.0 ML solution. placing I ML of the solution into a flask. and then perforn]ing Steps 2-5. From the results. each brand's iron Multivitamin (MV) tablets often contain iron in the fomofFe' 2+ In aqueous solution, Fe does not absorb vis- ible ligbt. However, when o-phenanthroline (o-phen) is present, it interacts with Fe . to form an orange-colored complex, which absorbs visible light at a wavelength of 508 nanometers (nm). 2+ (Fe ) content, in mg/tabJet, was calculated. Table 2 com- pares, for each brand, the calculated content with the iron 2+ (Fe ) content stated on the label. Students measured the absorbance at 508 nm the 2* then determined the Fe content of 4 brands of MV tablets (Brands A-D). Table 2 Stated iron Calculated iron (Fe ") content (mgltablet) Experiment I Steps 1-5 were performed 6 times: I, A certain volume of an aqueous stock solution having a concentration of 0.04 mg Fe'lmL was placed in a

Paper 27 · ACT April 2018 · Form A09 · Science Test

Suppose that in Experiment l. a seventh solution had been formed, beginning with 6 ML of the stock solu- tion. Based on Table I, if the A508 of the seventh solu- tion had been measured, it would most likely have been closest to which of the following. Table I 2+ Volume of stock solution (ML) concentration (mglmL) Solution 508

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on Tables l and 2, the solution of which brand of MV tablet most likely had the greatest A$08 value in Experiment 2 ? ACT.A09 46 GO ON TO THE NEXT PAGE. 40000000004

Paper 27 · ACT April 2018 · Form A09 · Science Test

Which of the following graphs best shows the relation- ship between Fe mentl?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consider the stock solution that was placed in a flask in Step l. Was this solution more likely orange or colorless? light. ble light. light. ible light. ACT-AO? 47 GO ON TO THE NEXT PAGE. 40000000004 Passage Vl fair weather days A study was donc in a large city in Asia during the spring to examine the Composition of airborne dust parti- cles on 5 day5 of fair weather and on 5 days of dust stornis. There was no precipitation on any of the study days. Study A device called an impactor (sce Figure l) was installed on the roof of a 4-story building in the center of the city. To collect airborne dust particles, the impactor drew in air at a constant rate of 1.1 Llmin. A series of 8 filters inside the impactor rernoved particles from the air. Each filter had openings of a different unifonn diameter to allow for the collection of particles belonging to l of 8 dif- ferent size ranges, measured in micrometers {￿M). Ke), Key E 0.16 filters ?))JJ))- air out air in Figure I On each of the selected days, the impactor was oper- ated continuously over a period that began at 9 a.m. Ai 3 p.m., the impactor was turned off, and the collected parti- cles belonging to each size range were removed and then anajyzed for 4 elements.. silicon {Si), iron (Fe), sult-ur (S), and copper (Cu). The average concentration of each ele- ment, in micrograms per cubic meter of air (Hglm ), for the fair weather days and for the dust stonn days are shown in Figures 2 and 3, respectively. for each size range. dust particle size range (Hm) Figure 2 ACT.A09 48 GO ON TO THE NEXT PAGE. 40000000004 dust storni days

Paper 27 · ACT April 2018 · Form A09 · Science Test

In Experiment I, was the volume of H O that had to be added to the flask in Step 4 to fonn Solution 2 greater than or less than the volume of H O that had to be added to the flask in Step 4 to fom Solution 5 ? larger volurne of Solution 2 than of Solution 5. smaller volume of Solution 2 than of Solution 5. smaller volume of Solution 2 than of Solution 5. larger volume of Solution 2 than of Solution 5. 2+ concentration and A508 in Experi- 2+ Fe concentration 2+ Fe concentration

Paper 27 · ACT April 2018 · Form A09 · Science Test

What was the purpose of Step 3, the addition of o-phen to the flask? The o-phen interacted with: 2+ 2+ 2+ 2+ Fe concentration 2+ Fe concentration

Paper 27 · ACT April 2018 · Form A09 · Science Test

Experiments l and 2 were most likely related to each other in which of the following ways? 2* Experiment I were used to detern]ine the Fe con- tents of Brands A-D in Experiment 2. 2+ Experiment 2 were used to determine the AJ08 values of Solutions 1-6 in Experiment I, 508 values of Solutions 1-6 measured in 2+ Experiment 2 were used to deterniine the Fe con- tents of Brands A-D Én Experiment l . 2+ Experiment I were used to determine the A508 values of Solutions 1-6 in Experiment 2.

Paper 27 · ACT April 2018 · Form A09 · Science Test

Consid¢r the results of fhe study for the dust storm days. Did the larger dust particles (> 2.0 Hm) or the smaller dust particles (< 2.0 Hm) have the greater aver- age concentrations of Si and Fe, and did the larger dust particles or the smaller dust panicles have the greater average concentrations of S and Cu ? eater Si and Fe greater S and Cu larg¢r dust particl¢s smaller dust particles smaller dust particles 14rger dust particles smaljer dust particles smaller dust particles

Paper 27 · ACT April 2018 · Form A09 · Science Test

Th¢ total volume of air, in liters, that was drawn through the impactor each hour is given by which of the following eApressions? .A. 1.1 Llmin x 60 min 10 Key

Paper 27 · ACT April 2018 · Form A09 · Science Test

Days with no precipitation were most likely chosen as study days because precipitation would have: caused dust particles in the air to condense. caused dust particles in the air to vaporize.

Paper 27 · ACT April 2018 · Form A09 · Science Test

What was the average mass of the < 0.25 Hm dust par- ticles that were collected by the impactor on the fair weather days?

Paper 27 · ACT April 2018 · Form A09 · Science Test

For both the fair weather days and the dust storm days. why were the results for Si and Fe plottcd on a aiffer- cnt y-axis scale than were th¢ r¢sults for S and Cu ? concentrations in the particles than were S and Cu. concentrations in the particles than were S and Cu. particle size ranges than did particles containing S and Cu. particle size ranges than did particles containing S and Cu. dust particle size range (wn) Figure 3 Figures 2 and 3 adapted from Renjian Zhang et al., rhe Elemental Composition of Atmospherlc Particles at Belling during Asian Du8t Events in Spring 2004,° 2010 by the Taiwan Association for Aerosol Research.

Paper 27 · ACT April 2018 · Form A09 · Science Test

The average concentrations of how many of the ele- ments were generally greater for the dust storm days than for the fair weather days?

Paper 27 · ACT April 2018 · Form A09 · Science Test

Based on the description of the design of the impactor, partKcles belonging to which size range were removed from the air by the first filter the air passed through? < 0.25 > 16.0 END OF TEST 4 STOPI DO NOT RETURN TO ANY OTHER TEST. ACT.A09 49 Scorlng Keys for Form Aog Use the scoring key for each test to score your answer document for the multiple-choice tests. Mark a "1" in the blank for each question you answered correctly. Add up the numbers in each reporting category and enter the totsl number correct for each reporting category in the blanks provided. Also enter the total number correct for each test in the blanks provided. The total number correct for each test is the sum of the number correct in each reporting category. Test 1: Engllsh-scorlng Key Reportlng Catego pow Reportlng Catego pow *Reportlng Categorle8 POW =. Productlon of Wrfting KLA = Knowledge ol Language CSE = Convention8 of Standard English Koy CSE Koy CSE