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OFFICIAL ACT Form E23 · 12 2021

Science

39 questions ~9 min recommended
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=== Passage I ===
Table 2 The freezing point of an aqueous solution (T), in °C, can be calculated using the equation T =−1.86 ×m×i where m is the concentration of the solute in moles of solute per kilogram of H O (mol/kg H O) and i is the average number of particles produced by 1 formula unit of the solute when the formula unit dissolves in H O. Table 1 gives, for 4 ionic compounds, the chemical formula and the theoretical i value. Table2 shows how the observed i value at 25°C for these compounds changes with solute concentration. Chemical Name formula Theoretical ivalue Sodium chloride NaCl 2 Potassium chloride KCl 2 Magnesium chloride MgCl 3 Ammonium sulfate (NH ) SO 3

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rbing D. produced by microbial metabolism, whereas effects of the 3 greenhouse gases, maintaining an average according to Hypothesis 2, CH was produced by chemical reactions between CO and H O. 2 2 44 GO ON TO THE NEXT PAGE. ACT-E23 4 4 24. The metabolism of the microbes referred to in Hypoth- 26. Suppose that if Earth’s atmospheric N concentration 2 hypothesis 1 is most likely represented by which of the fol- were increased from its present value, the atmosphere lowing balanced chemical equations? would scatter a higher percentage of incoming sun- light, resulting in cooler surface temperatures. This F. CO +4H →CH +2H O information would weaken which of the hypotheses, if 2 2 4 2 either? G. CO 2 +2H 2 O →CH 4 +2O 2 H. CH +2O →CO +2H O F. Hypothesis 1 only 4 2 2 2 G. Hypothesis 2 only H. Both Hypothesis 1 and Hypothesis 2 J. Neither Hypothesis 1 nor Hypothesis 2 25. Hypothesis1 would be best supported by which of the J. CH 4 +2H 2 O →CO 2 +4H 2 following findings involving CO or CH ? 2 4 A. Evidence that 4billion years ago the concentration of CO was 20 times the present concentration 2 B. Evidence that 4billion years ago the concentration of CH was 20 times the present concentration 4 C. 3.5-billion-year-old rock samples containing evi- dence of CO produced by microbes 2 D. 3.5-billion-year-old rock samples containing evi- dence of CH produced by microbes 4 45 GO ON TO THE NEXT PAGE. ACT-E23 4 4 Passage V Study 2 The students measured F for a fluid having an η of Viscous fluid flow occurs when various parts of a fluid 1.0×10 −3Pa·sec that flowed through each of various tubes interact with each other to produce forces that inhibit flow having the same D, 1.00 m, but different R(see Table 2). and generate heat. Students performed 3 studies of viscous fluid flow using the experimental setup shown in Figure1 below.

1. Based on Table 2, what is the observed i value for a 0.6 mol/kgH O solution of (NH ) SO ?

2. According to Table2, which compounds have observed ivalue less than 2.50 at all the concentrations listed?

3. According to Table 2, at which of the following concentrations is the observed ivalue for KCl the lowest?

4. Based on Tables 1 and 2, which ionic compound has the largest deviation from its theoretical i value at a concentration of 2.0 mol/kg H O?

5. Consider the following substances: sodium chloride, potassium chloride, magnesium chloride, ammonium sulfate, and water. Which of these substances would be classified as a solvent in the solutions represented in Table 2?

6. Sucrose (C H O ) is a molecular compound and remains intact when it dissolves in water. Would the theoretical i value for C H O more likely be less than that of KCl or greater than that of KCl?

7. Based on Table 1, as streptomycin concentration increased, the relative fitness of Strain Y:

8. Based on Table 1, if Strain X had been exposed for 24hr to a streptomycin concentration of 3 μg/mL, its relative fitness would most likely have been:

9. According to Table 2, which statement best describes the effect of the mutation in StrainX cells?

10. Suppose an equal number of Strain W cells and Strain X cells were exposed for 24 hr to a streptomycin concentration of 2 μg/mL. Based on Table 1, which of Strain W or Strain X would more likely have the greater number of cells survive and reproduce?

11. According to Table 1, what was the relative fitness of the strain exposed to a streptomycin concentration of 4 μg/mL?

12. In the absence of an antibiotic, what was the relative fitness of the nonmutated strain?

13. How many times in Experiment 2 was a bottle placed into the box when the box was maintained at 10°C?

14. Suppose that in Experiment 2 the bottle containing water stored at 50°C had been reused 35 times. At that reuse number, the approximate concentration of Sb3+ in the water would have been:

15. Assume that the maximum acceptable concentration of Sb3+ in drinking water is 6,000 ng/L. This concentration of Sb3+ is how many times as great as the concentration of Sb3+ in water stored at 50°C in a bottle that was reused 21 times in Experiment 2?

16. Which set of experimental conditions resulted in an Sb3+ concentration of 140 ng/L in water stored in a bottle that had been reused 14 times?

17. The substance composing the bottles tested in the experiments is best classified as which of the following?

18. Suppose that in Experiment 1 a temperature of 20°C had been tested. At a reuse number of 21, the Sb3+ concentration would most likely have been between:

19. Did Experiment 1 and Experiment 2, respectively, take more than 1 day or less than 1 day to complete?

20. A supporter of Hypothesis 1 and a supporter of Hypothesis 2 would be likely to agree that, during the early Earth period, magma from beneath Earth’s crust contained:

21. Suppose that the current atmospheric CO2 concentration on Earth is approximately 395 parts per million (ppm). Based on Hypothesis 2, the atmospheric CO2 concentration on early Earth was most likely closest to which of the following values?

22. Which of the hypotheses, if either, indicated that additional gases were necessary for CO2, NH3, and CH4 to absorb enough heat for liquid water to exist on early Earth’s surface?

23. In regard to the source of CH4 in early Earth’s atmosphere, which of the following statements describes a difference between Hypothesis 1 and Hypothesis 2?

24. The metabolism of the microbes referred to in Hypoth- 26. Suppose that if Earth’s atmospheric N concentration were increased from its present value, the atmosphere would scatter a higher percentage of incoming sun- light, resulting in cooler surface temperatures. This information would weaken which of the hypotheses, if either?

25. Hypothesis1 would be best supported by which of the following findings involving CO or CH?

26. Suppose that a sixth trial had been performed in Study 1 for which the fluid’s flow rate had equaled 920 mL/sec. In that trial, the viscosity of the fluid would most likely have been:

27. In Study 2, which variables were held constant?

28. Based on the information given, if the pressure at Gauge G was 105 kPa, what was the pressure at Gauge H?

29. Based on the information given, in what direction was the fluid flowing?

30. The viscosity of each fluid investigated in the studies resulted from which of the following types of interactions between parts of the fluid?

31. In Study 3, when D was equal to 2.50 m, approximately what volume of fluid flowed past either gauge in 1 minute?

32. The pressure gradient between any 2 points lying on a horizontal line inside a tube equaled the absolute value of the difference in pressure between the 2 points divided by the distance between the 2 points. What was the pressure gradient between Gauges G and H during Study 1?

33. According to the results of Study 1, from 3 days after treatment through 9 days after treatment, the average number of seeds that had germinated per pot for Group 4: was

34. Based on the results of Study 2, how many of the groups had an average plant height greater than 1 meter?

35. The presence of more than 1 plant in a pot can negatively affect the growth of all the plants in the pot, due to competition among the plants. What action was taken in Study 2 to prevent competition among the plants?

36. Consider the claim 'The average height of the plants in a group was affected by the number of days that the pots in that group were irrigated.' Can this claim be evaluated on the basis of the results of Study 2?

37. Consider the statement 'Treatment with Species R was more effective at promoting seed germination in soil with a higher-than-normal NaCl concentration than treatment with PMA.' Are the results of Study 1 consistent with this statement?

38. Let x represent the number of days after treatment until germination was first observed among the Group 2 pots in Study 1. Based on the results of Study 1, x is given by which of the following expressions?

39. Consider the statement 'On average, plant height was greater for the plants treated with H O containing PMA and NaCl than it was for the plants treated with either H O containing NaCl only or H O containing Species R and NaCl.' Do the results of Study 2 support this statement?

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