ACT Past Papers with Answers

Paper 21 · ACT December 2019 · Form C03 · Science Test

2 L.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on Tables l and 2. at any given lemperature and pressure, the molar volume of which other gas is most similar to the molar volume of O ? ACT.C03 39 GO ON TO THE NEXT PAGE. 40000000004 Passage11 Scientists conducted 3 experiments to study the trans- fer of bacteria from one surface to another by 2 species of flies: Musca domesiica and Sarcopha8a carnaria. Experimenr I A group of 10 M. domeslica was tested using ihi5 procedure: Experimeni 3 The procedure from Experiment I w&8 repeated with each of 3 groups of 10 S. carnaria excepi thai, after Step l. the flies in each group were allowed a differeni period of time-o min. 30 min, or 60 min to clean themselves before each fly was placed in a separate petri dish Lontain- ing sterile nutrient agar. The results are shown in Figure 3. l. Each fly was placed in a separate enclo.sure containing Escherichia coli (a type of bacieria) and allowed io walk on the E. coli for 5 min.

Paper 21 · ACT December 2019 · Form C03 · Science Test

An ideal gas h25 a molar volume of 63.429 L ai l.(K) atm and 773 K. At l.(M) atm and 773 K. how many of the gases listed in Table 2 have a smaller molar volume than thai of an ideal gas? S. In a gas sample. collisions belween gas particles are common. The average time a gas particle spends between one collision and the nexl is called ihe mean free lime. In general, mean free time decreases as a sample's volume decreases. Based on Table l. Ihe mean free time would be leasi for a I mol sample of ,hich ga% ai which pressure.

Paper 21 · ACT December 2019 · Form C03 · Science Test

The tank, lubes, and electrod¢s were cleaned and dried for reuse. Figures and table adapted from Sergii Be8palko, "Hydrogon Pro- ducllon by Water Electrochemical Phololysls Using PV-Module.' V2011 by Sorgii Bespalko. ACTQI3 46 GO ON TO THE NEXT PAGE. 40000000004 Pa88age Vl slanding wave on a taui string is a wave that appears to vibrate without traveling along the string. Such waves are called the string s hannonics. Each harmonic has a characteristic number of nodes: locations between the ends of the string that do not move (the ends of the string do not count as nodes). Figure l illustrates a harmonic and also ihe apparatus that a student used to perfonn 2 experi- menis on standing waves. Table I f (Hz) for String: Harmonic Sketch 1st

Paper 21 · ACT December 2019 · Form C03 · Science Test

Consider 2 s¢paraie I mol samples of O , each al a pressure of l alm. One sample has a volume of aboul 18 L, and the other has a volume of about 63 L. Based on Table 2, the average kinetic energy of the 02 mole- cules is more likely greater in which .sample? temperature. temperature. lemperature. temperature.

Paper 21 · ACT December 2019 · Form C03 · Science Test

As the amount of cleaning lime increased, the average number of colonies per dish: increased only. increased fdnd then decreased. Figure I Experiment 2 The procedure from Experimenl I wa5 repeated with each of 3 groups of 10 S. carnaria except ihal the flies in each group were allowed to walk on the E. coli for a differ- ent period of lime 5 min. 30 min, or 60 min before each fly was placed in a separale petri dish containing nutrieni agar. The results are shown in Figure 2. What was the tolal number of flies tested in Experi- ment3? 80

Paper 21 · ACT December 2019 · Form C03 · Science Test

0 L. because Step 2 was performed twice in June. once on June l and once on June 30. June, once each day. June. twice each day.

Paper 21 · ACT December 2019 · Form C03 · Science Test

A scientist claimed thai some specie.s of flies spread bacterial diseases. Are ihe results of Exper2ment I con- sislent wilh ihis claAm? ria from one surface to another. bacteria lo S. carnaria. bacteria from one surface to another. fer bacteria io S. carnaria. 20 30 time spent walking on E. coli Imin) Figure 2 ACTQ 40 GO ON TO THE NEXT PAGE. 40000000004

Paper 21 · ACT December 2019 · Form C03 · Science Test

In the experiments, why was il necessary for the nutri- ent agar in the petri dishes to be sierile until the flies were placed in the dish¢s. bacteria pre.sent in the nutrient agar before the flies were placed in the dishes bacteria iransferred io the nutrient agar by the flies nutrients necessary for the flies to reproduce nuirienis necessary for ihe bacteria to reproduce

Paper 21 · ACT December 2019 · Form C03 · Science Test

A sludeni claimed that Species X flies would transfer more E. coli cells to a pelri dish containing nutrient agar than would either M. domestica or S. carnaria. Which of the following ¢xperimenls would best lesl the student's claim. 10 SpeLies X flies. speLies of bacteria. 10 Species X flies. species of bacteria. 41 GO ON TO THE NEXT PAGE. 40000000004 Pa88age 111 Forest fires require oxygen (02) io burn. Figure I shows the nutnber of paleowildfires (large forest fires known from the rock record) for each 10-million-year Interval of rhe Mesozoic era (250-65 million years ago. mya). Figure l also shows a model of the percent 02 by volume (%02) in Earth's a(mosphere from 250 mya to 70 mya. Key %0. number of known paleowÉldfire5 20 15 10 millions of years ago (mya) Figure I To study how Yo02 affects burning scientists altempted to igniie 7 samples of each of 4 differenl mate- rials. I sample at a lime. in a chamber. For each sel of sam- ples of the same materlal. the initial %02 in ihe chamber ranged fmm 12% to 18%. Figure 2 shows. for each sample that ignited, the duraiion of ihe sample's flame. Kei. candle ..￿... dry paper malLh pine w(KKI 12 10 12 13 14 15 16 J7 18 initial %0. in chamber Note.. At an initial %0: of 18. all Samples burned io ash in 12 second%. Figure 2 Figures adapted from C. M. B81chef an(J J. C. McElwain. "Limlts tor Combu51ion in Low O Redefine Paleoalmospherfc Predictions for the Mesozoic." Q2008 by American Association lor the Advance- ment ol Science. ACT£OJ 42 GO ON TO THE NEXT PAGE. 40000000004

Paper 21 · ACT December 2019 · Form C03 · Science Test

Which of the following statements gives the mosl likely hypoihesis for Experimeni 3 themselves. more bacteria they transfer between surfaces. faces than do S. carnaria. during cleaning than are S. carnaria.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Which of the following IS the most likely iea50n ihat the average number of colonies per dish for S. carnaria shown in Figure I was differeni from the average number of colonies per dish for the flies ihal spenl 5 min walking on the E. coli in Experiment 2 ? Iran5ferred, on average. fewer E. coli than did the . carnaria in Experimenl l. ferred. on average. fewer E. coli than did the carnaria in Experiment l. coli for a shorter period of time th4in did the carnaria in Experimeni l. coli for a shorter period of lime than did the carnaria in Experiment l.

Paper 21 · ACT December 2019 · Form C03 · Science Test

The %0? in Earth's atmosphere today is about 21. ALcording io Figure I, at which of the following times during the Mesozoic era was the %02 in Earth's almo- sphere closest to ihe %02 Rn Earth's atmosphere today. l (M) mya

Paper 21 · ACT December 2019 · Form C03 · Science Test

According to Figure 2. at an initial %0: of 17. approx- imalely how many seconds greater was ihe flame dura- tion for dry paper than ihe flame duralion for pine wood?

Paper 21 · ACT December 2019 · Form C03 · Science Test

A scienti.sl claimed ihai paleowildfires could only have occurred when ihe <700* was higher than 15. For which of the following time iniervals during the Mesozoic era are the data in Figure l iiic'ipnsislenl Wlth ihis claim? 90-70 mya

Paper 21 · ACT December 2019 · Form C03 · Science Test

According to Figure 2. what is the order of the 4 mate- rials lested. from ihe material that required the highest initial %0 to igniie to the material that required the lowesi initial %02 to ignile.

Paper 21 · ACT December 2019 · Form C03 · Science Test

According to Figur¢ I, how many paleowildfires are known from ihe rock record between 95 mya and 85mya?

Paper 21 · ACT December 2019 · Form C03 · Science Test

According to Figure 2, at an initial of 16, which of the 4 malerials sus(ained a flame the longest? Dry paper ACT.C03 43 GO ON TO THE NEXT PAGE. 40000000004 Pa88age IV

Paper 21 · ACT December 2019 · Form C03 · Science Test

Which student would be ihe most likely to agree that the soil in which a Population A plani is grown will influence its slem color? Four siudents observed that in a population of land planls, Population A, a plant could have a green stem or a purple stem. Each student proposed an explanation for this observation. Siudeni J All plants in Population A produce the green pigmenl chlorophyll. If a planl receives 8 hr or more of sunlighi each day. it also produces a purple pigment, causing its siem io be purple. If a plant receives less (han 8 hr of sun- light each day. it does not produce this purple pigment. so Its stem is green. All plants in Population A are genetically identiLal. 50 ihey all have the abilily to produce boih Pl8menis.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Suppose it were found ihai the presence of the purple pigment in some plant lissues proiects those ti.ssues from being damaged by sunlight. Would ihis fjnding better suppori ihe explanation of Siudent l or the explana(ion of Studeni 2 ? planls receiving ihe mosl sunlighi will have purple Student I, because Student l indicated ihat the plants receiving the mosl sunlight will have green slems. planls receiving the mosl sunlight will have purple stems. plants receiving ihe most sunlighi will have green siems. Siudeni 2 All plants in Population A produce the green pigment chlorophyll. If a plant receives loo little phosphorus (a nutrient). il also produces a purple pigment. causing ils stem io be purple. If a planl receives enough phosphorus. it does not produce this purple pigmeni. so ils stem is green. All plants in Populaiion A are genetically identical, so they all have the ability to produce both pigmenis. The amounl of sunlighi received by a plani does noi affect stem color. Siudeni 3 All plants in Population A produce the green pigment chlorophyll. The production of purple pigment is deier- mined by Gene Q. whiLh has 2 allele.s (Q and q) and 3 pos- sible genoiypes (QQ. Qq. and qq). A plani with either ihe Gene Q genotype QQ the Gene Q genoiype Qq produces Ihe purple pigment. causing its siem to be purple. A plant wilh the Gene Q genotype qq doe5 not produce this purple pigment. so ils slem is green. The amount of sunlighi or nutrients received by a plant does nol affect stem color.

Paper 21 · ACT December 2019 · Form C03 · Science Test

All 4 of ihe students. explanations are consistent wilh which of the following staiernents? In Popuiaiion A: plants produce a pigment that can be used for photosynthesis. only green-stemmed plants produce a pigment thal can be used for photosynthcsis. only purple-siemmed plants produce a pigment thal can be used for pholo%ynthe%is. neither green-stemmed plants nor purple-5temmed plants produce a pigmeni that can be used for photosynthesis. Siudeni 4 ARI planis in Population A produce the green pigment chlorophyll. The production of purple pigment 15 deter- mftned by Gene Q. which has 2 alleles (Q and q) and 3 pos- sible genotypes (QQ. Qq, and qq). A plant wilh the Gene Q genotype qq produces ihe purple pigment, causing ils stem to be purple. A plant with eiih¢r the Gene Q genoiype QQ or the Gene Q genotype Qq does noi produce this purple pigmeni. so its stem is green. The amounl of sunlight or nutrients received by a plani does not affecl stem color. ACT<OJ 44 GO ON TO THE NEXT PAGE. 40000000004

Paper 21 · ACT December 2019 · Form C03 · Science Test

Which of the students. if any. would be likely to agree thai providing a purple-stemmed plant from Popula- tion A with additional sunlight will cause Its stem to become green.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Suppose 2 of the purple-stemmed plants in the popu- lation were crossed and .$? purple-stemmed and 15 green-sleTnmed offspring were produced. If all ihe parents and offspring in the cross were grown under the same conditions, Ihese results would best support the explanation of which sludent?

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on Student 4's explanation, if a purple-stemmed plani and a green-sternmed plant from Population A are crossed and they produce l)oth purple-stemmed off- spring and green-siemmed offspring, Ihe Gene Q geno- iype of the parent with the:

Paper 21 · ACT December 2019 · Form C03 · Science Test

Whlch of the sluden15 would be likely to agree that a plant receiving 9 hr of sunlight each day could have either a purple siem or a green siem. ACT<03 45 GO ON TO THE NEXT PAGE. 40000000004 Pa858ge V Figure 2 shows the total volume of H2 produced (in L) in each monih of the experimeni. Table I shows the aver- age solar irradiance {power per unil area), in wati.s per square meter (Wlm ), at the localion of ihe solar cell during each month of the experiment. Liquid H O can be broken down Anto hydrogcn gas (H2) and oxygen gas (02) by elecirolysis according to the following chemical equation: 2H,O->2H +0 A scientist performed an experiment lo sludy the elec- trolysis of H O using electricily generated from sunlight. i(x) Experimenl S¢¢ps 1-5 were perfornied daily for 12 months: l. A tank fitted with 2 elecirodes an anode (where O. would be produced) and a carhode (where H2 would be produced)-was assembled. Each electrode was SUS- pended in an inverted plastic lube. and eaLh lube was marked to allow gas volurne to be measured.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on Figure 2 and Table l. during the month in which a total of 70 L of H was produced. the average solar I￿adianCe was..

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on the description of ihe experiment, al 4:00 p.m. on each day. did the scientist measure the amounl of gas produced ai the anode or the cathode? produced. pr(Kluced. produced. produced.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Consider the percent by mass of NaOH in the solution added io the tank in Slep 2. Approximately what mass of NaOH was in 200 g of this solulion? 25g 50g

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on the chemical equalion and Figure 2, approxi- mately how many liier8 of 02 (N(yr H2) were produced in Febru<￿. 20L 40L 80L IOOL ACT.CI)g 47 GO ON TO THE NEXT PAGE. 40000000004

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on the description of the experiment, in ihe month of June bow many total liters of NaOH solution were added to the tank? onJune l.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on Table l. on May I l. was the solar irradiance of ihe solar cell less than, equal to, or greaier than

Paper 21 · ACT December 2019 · Form C03 · Science Test

Suppose the experiment was repealed. excepi ihat the scieniist added only pure liquid H:0 to the tank in Step 2. Based on ihe descripiion of the experiment, would this Lhange have more likely resulted in more H: being produced or less H: being produced? higher electrical conduclivily than does an aque- ous NaOH solution. More H pure liquid H:0 has fewer ions and ihus lower electrical conductivily than does an aqueou5 NaOH solulion. higher electrical conductivity than does an aque- ous NaOH solution. lower electrical conductivily than does an aqueous NaOH solution.

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on the sketches made in Experiment I, the string shown in Figure l is vibrating in which hannonic?

Paper 21 · ACT December 2019 · Form C03 · Science Test

In a new trial, the sludent made the following sketch of a slandftng wave on String Z. Based on the results of Experimenis l and 2. this standing wave occurred at which approximate values off and T ?

Paper 21 · ACT December 2019 · Form C03 · Science Test

A piece of String Y ihat is I cm in length would have the same mass as a piece of:

Paper 21 · ACT December 2019 · Form C03 · Science Test

The student reported the da(a in Table I WAth how many significani digils and some were ieponed wilh 2 significant digils. Some data were reported with 2 significant digits. and some were reported wilh 3 significant digils.

Paper 21 · ACT December 2019 · Form C03 · Science Test

For a string at constant tension, let f. represent the fre- quency of the nth harnionic (fi IS the frequency of the I st harn]onic, f2 IS the frequency of the 2nd harmonic. f3 IS the frequency of the 3rd harmonic. and so on). Which of the following equations for f. is consisient with the resulis of Experiment I for String X ? n+fi

Paper 21 · ACT December 2019 · Form C03 · Science Test

Suppose thai a string having a mass per unit Jength of 0.32 glcm had been tested in Experiment 2. The 4th harmonic of this strin8 would most likely have occurred ai a tension:

Paper 21 · ACT December 2019 · Form C03 · Science Test

Based on the results of Experiments l and 2. for a given harmonic. as H increased, did f increase or decrease, and did T increase or deLrease. increased increased increased decreased increased decreased END OF TEST 4 STOPI DO NOT RETURN TO ANY OTHER TEST. ACT403 49 Scorlng Keys for Form C03 Use the scoring key for each test to score your answer document for the multiple<￿iCe tests. Mark a "1" in the blank for each question you answered correctly. Add up the numbers in each reporting category and enter the total number correct for each reporting category in the blanks provided. Also eniei the total number correct for each test in Ihe blanks provided. The total number correct fof each test is the sum of the number correct in each reporting caiegory. Te8t 1: Engll8h-Scorlng Key Aeportlng Category. pow CSE R•portlng Catègory. "Reportlng Categorle8 POW - Production of Writing KLA - Knowledge of Language CSE = Conventions ot Standard Engllsh Key Key