ACT Science Homework Science 2, Set 1 35 Minutes 38 Questions Passage I DIRECTIONS: There are seven passages in this test. Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary. You are NOT permitted to use a calculator on this test. Reaction rates measure how quickly a chemical reaction takes place. There are many factors that can affect reaction rate: the concentration of the reactants, the temperature of a reaction, and the physical size of the reactants are some examples. Experiment 1 A 5 g piece of calcium carbonate was placed in test tubes with different concentrations (measured in moles or M) of hydrochloric acid. The time it took the acid to dissolve the calcium carbonate was recorded. Concentration of acid Time to dissolve 1 M 93 sec 3 M 58 sec 5 M 32 sec Experiment 2 3 different volumes of 5 grams of calcium carbonate were placed in test tubes with 3 M hydrochloric acid. The time it took the acid to dissolve the calcium carbonate was recorded. Volume of calcium carbonate Time to dissolve 5 cm 3 56 sec 10 cm 3 28 sec 15 cm 3 13 sec Experiment 3 The amount of 3 M hydrochloric acid was varied when mixed with 5 g of calcium carbonate with a volume of 10 ml. The time it took for the calcium carbonate to dissolve was recorded. Volume of hydrochloric acid Time to dissolve 3 ml 42 sec 5 ml 39 sec 7 ml 13 sec 1
1. Which of the following reaction rates was not tested? A. Temperature of the reaction B. Volume of hydrochloric acid C. Concentration of hydrochloric acid D. Volume of calcium carbonate 4. In Experiment 2, what was actually being varied? F. The amount of calcium carbonate being added G. The amount of hydrochloric acid being added H. The concentration of hydrochloric acid being added J. The volume of calcium carbonate being added 2. In Experiment 2, the volume of the calcium carbonate was studied. Which of the following volumes would have the fastest reaction time? F. 15 cm 3 G. 18 cm 3 H. 17 cm 3 J. 16 cm 3 5. Experiment 1 measures reaction time by testing which variable? A. The time it took the calcium carbonate to dissolve B. The amount of calcium carbonate used C. The concentration of hydrochloric acid D. The amount of hydrochloric acid 3. In Experiment 3, as the amount of acid was increased, the reaction rate: A. Sped up B. Slowed down C. Sped up and then slowed down D. Slowed down and then sped up 6. What set of circumstances will most optimize reaction time? F. Large volume of strong hydrochloric acid with a large volume of calcium chloride G. Small volume of strong hydrochloric acid with a large volume of calcium chloride H. Large volume of weak hydrochloric acid with a large volume of calcium chloride J. Small volume of weak hydrochloric acid with a large volume of calcium chloride 2
Passage II Simple machines do a lot to improve how much effort needs to be put into a job in order for it to be done. The amount of effort these machines save is called the mechanical advantage. It is calculated as the factor by which it multiplies an applied force. The mechanical advantage is listed for each experiment. The higher the mechanical advantage, the easier the job becomes. Experiment 1 A 20 kg object needed to be rolled up an inclined plane. Several different planes were available. Length Height Mechanical advantage Plane 1 15m 5m 3 Plane 2 30m 5m 6 Plane 3 45m 5m 9 Plane 4 10m 5m 2 Experiment 2 This same object is lifted up the distance it needs to go by a set of levers. Effort arm length Resistance arm length Mechanical advantage First class lever 10m 2m 5 Second class lever 15m 10m 3 Third class lever 2m 10m.2 3
Experiment 3 This same 20 kg object can be lifted the 5m with a pulley. moveable puley fixed pulley Fixed or moveable Effort distance Resistance distance Mechanical advantage Pulley 1 Fixed 5m 5m 1 Pulley 2 Fixed 7m 7m 1 Pulley 3 Moveable 10m 5m 2 Pulley 4 Moveable 15m 5m 3 http://www.howe.k12.ok.us/~jimaskew/ps/pmachine.htm source material 4
7. Which simple machine made the job the easiest? A. Third class lever B. Inclined plane 3 C. Inclined plane 2 D. Pulley 3 10. Why are long inclined planes seldom built as ramps? F. Though they have increased mechanical advantage, they are too long and the slope too gradual to be practical. G. Though they have increased mechanical advantage, they are too steep to be practical. H. With a small mechanical advantage, they are a waste of space. J. Further study should be done to determine their usefulness. 8. What is the relationship between effort arm and resistance arm in a third class lever? F. The fulcrum is between the resistance arm and the effort arm. G. The resistance arm is between the fulcrum and the effort arm. H. The effort arm is between the resistance and the fulcrum. J. It is impossible to determine the relationship. 11. Why does a third class lever have a smaller mechanical advantage? A. The resistance force does not move as far as the effort force, making the change in distance not direction. B. The fulcrum makes it more balanced. C. The resistance force and effort force are balanced, and so there is no mechanical advantage. D. The effort force does not move as far as the resistance. 9. Why does the fixed pulley only have a mechanical advantage of one? A. The effort distance is always greater than the resistance distance. B. The effort distance and the resistance distance always have to be the same. C. The resistance distance is always less than the effort distance. D. The effort distance and the resistance distance are always changing. 12. If a large, heavy object needed to be moved to a higher platform, which pulley would be the most effective? F. A fixed pulley because it will allow the force of the heavy object to be in the same direction as it is being pulled. G.A fixed pulley because it will allow the direction of the force to be changed, so someone can pull in the opposite direction of the heavy object. H. A moveable pulley because it will allow the person pulling the object to pull in the same direction as the object is being moved. J. A moveable pulley because its mechanical advantage is higher. 5
Passage III Enzymes catalyze reactions; they make them work. Some factors speed or slow the enzyme. Several factors were studied. Each study was allowed to react until the reaction stopped. Reaction percent was calculated using the theoretical yield compared to the actual. The amount of the reactants was the same for each study. Experiment 1 The temperature at which the reaction took place was studied. The percentage is the percent maximum activity. Temperature in Celsius Percent activity 0 5 10 8 20 20 30 45 40 95 50 35 60 5 70 2 Effect of Temperature 100 Percent Activity 80 60 40 20 0 0 10 20 30 40 50 60 70 Temperature in Celcius Percent activity Experiment 2 The ph of the solution that holds the same enzyme and the reaction also affects the rate at which the enzyme works. The lower the ph, the more acidic the solution. ph Percent activity 1 5 2 25 3 55 4 89 5 60 6 20 7 5 8 2 6
Effect of ph 100 Percent activity 80 60 40 20 0 1 2 3 4 5 6 7 8 ph Series1 Experiment 3 The concentration of the enzyme was studied. The concentration is measured in moles. Enzyme concentration Percent activity (in moles).5 20.75 40 1 60 1.25 80 1.5 85 1.75 0 http://ghs.gresham.k12.or.us/science/ps/sci/soph/enzyme/enzfactorstemp.htm source material 7
13. At which point does the temperature have a negative affect on the reaction rate? A. 35 B. 45 C. 55 D. 25 14. Based on the data in Experiment 2, if the enzyme activity had been measured when the ph of the solution was 4.5, it most likely would have been: F. 110 G. 98 H. 70 J. 55 16. Another enzyme behaves similarly to the enzyme studied. However, this enzyme is activated at a higher temperature and a more acidic environment. If the model environment is to be designed for it, it would be F. Temperature=40, ph=3.5, enzyme concentration=1.5 G. Temperature= 50, ph=4, enzyme concentration=1.75 H. Temperature=40, ph=4, enzyme concentration= 1.5 J. Temperature=50, ph=3.5, enzyme concentration=1.5 17. According to the results of the experiment, as the temperature of the reaction increases, the enzyme activity A. Increases. B. Decreases. C. Increases to a point and then decreases. D. Decreases to a point and then increases. 15. The best possible conditions for this enzyme s work is A. Temperature=40, ph=4, enzyme concentration= 1.5 B. Temperature= 50, ph=4, enzyme concentration=1.75 C. Temperature=50, ph=3.5, enzyme concentration=1.5 D. Temperature=40, ph=3.5, enzyme concentration=1.5 18. As the amount of enzyme increases, the enzyme activity F. Increases to a point then decreases. G. Decreases. H. Decreases to a point then increases. J. Increases. 8
Passage IV Soil Types: Soil can be classified based on the size of particles and the overall composition. Three main classifications for soil include: sand (largest particles, rough texture, limited nutrients), silt (middle-sized particles, smooth and powdery texture when dry) and clay (smallest particles, smooth texture when dry but sticky when wet, nutrient rich). A combination of all three soils is often called loam. Scientists wanted to study a variety of properties of some of these soils and other soil types in order to determine the best soil for plants in their area. Experiment 1 Filtration Scientists dried and crushed each soil sample before placing it in a funnel lined with filter paper. They then placed the funnel over a beaker and poured 100ml of a dark blue dye through each sample. The resulting color of the dye was observed and recorded. The lighter the color, the more the soil filtered the water. Table 1 Soil Type Loam Sand Clay Final Color Medium Blue Dark Blue Light Blue Experiment 2 Wind Erosion Scientists took the same three types of soil from Experiment 1 and tested their resistance to wind erosion. The samples were dried and then placed on a table two meters from a fan. The fan was turned on, and the time to remove all of the soil was recorded. The longer it took to remove all of the soil, the more resistant the soil was to wind erosion. Wind Erosion Time (seconds) Loam Silt Clay 9
Experiment 3 ph The ph was tested and recorded using a ph meter for all five soil samples. The ph scale ranges from 0 to 14 (7 is neutral). The higher the ph, the more basic a substance; the lower the ph, the more acidic a substance. Table 2 Soil Type Loam Clay Sand Silt Peat ph 6.3 5.9 7.2 6.8 5.4 19. Which of the following diagrams best illustrates the set up of Experiment 1? C. A. D. 20. Broccoli and cauliflower both grow best in soils with a ph between 6.0 and 6.5. When planting these vegetables in a slightly windy area, which soil is best? F. Silt G. Clay H. Sand J. Loam B. 10
21. According to Experiment 1, which of the following lists the soils in order from most effective filtration to least effective filtration? A. Loam, Sand, Clay B. Clay, Loam, Sand C. Clay, Sand, Loam D. Loam, Clay, Sand 22. Researchers would like to test another type of soil - peat - in order to assess wind erosion resistance. Knowing that peat is a dense conglomerate of partially decayed vegetative material, how long would you expect it to take for the sample to be completely removed? F. 14.5 seconds G. 2.0 seconds H. 7.0seconds J. 7.5 seconds 23. If soil samples were wet, the time required for complete wind erosion would likely do which of the following? A. Remain the same, because water will not affect the soil s resistance to wind. B. Increase, for sand but stay the same for loam and clay because water only makes sand weigh more. C. Increase, because the samples would be weighted down by the water and therefore harder to move. D. Decrease, because water will make the samples more susceptible to wind erosion. 25. Which best represents the data from Experiment 3? A. B. C. 24. Not all soil can be classified as a pure sample of one of the main types listed. What would you expect the order (from lightest to darkest color) to be if Experiment 1 were repeated using the following combinations: F. Loam/sand, clay/sand, clay/loam G. Clay/loam, loam/sand, clay/loam H. Clay/loam, clay/sand, loam/sand J. Loam/sand, clay/loam, clay/sand D. 11
Passage V http://www.sciencejoywagon.com/physicszone/lesson/otherpub/wfendt/ohmslaw.htm source material Electrical current running through a circuit can be controlled in many ways. An amp is a measurement of how much current is moving through a circuit while a volt is a measure of how fast the current is moving. Some materials resist the flow of current; they are called resistors. The strength of a resistor is measured in Ohms, a ratio of the number of volts per amp. Study 1 In a closed circuit, the number of volts was varied. The amount of amps and ohms are listed in the table below. Volts Amps Ohms 100.02 5000 200.04 5000 300.06 5000 400.08 5000 500.1 5000 Study 2 In a closed circuit, the number of amps was varied. The amount of volts and ohms are listed in the table below. Volts Amps Ohms 100.0167 6000 100.0143 7000 100.0125 8000 100.0111 9000 100.01 10000 Study 3 This time, the ohms were varied. The amount of volts and amps are listed in the table below. Volts Amps Ohms 100 2.5 40 100 2 50 100 1.67 60 100 1.43 70 100 1.25 80 100 1.11 90 12
26. In a closed system, what is the relationship between volts and amps? F. When the amount of volts goes up, the number of amps stays the same. G. When the amount of amps goes up, the number of volts stays the same. H. When the number of volts goes up, the number of amps goes up. J. When the number of volts goes up, the number of amps goes down. 30. Would the amount of current have to be increased if the resistor was made stronger? F. Yes, there would have to be an increase in current to accommodate the increased resistance. G. No, the amount of current only changes with a change in amps. H. No, the amount of current in a closed circuit stays the same; the number of amps would decrease. J. No, the amount of current in a closed circuit stays the same; the number of amps would increase. 27. When ohms are varied what happens to the amps? A. As ohms decrease, amps decrease. B. As ohms decrease, amps stay the same. C. As ohms increase, amps increase. D. As ohms increase, amps decrease. 31. What is the difference between Study 2 and Study 3? A. In Study 2, the amps were varied while in Study 3 the ohms were varied. B. In Study 2, the ohms were varied while in Study 3 the ohms were varied. C. In Study 2, the volts were varied while in Study 3 the amps were varied. D. In Study 2, the amps were varied while in Study 3 the volts were varied. 28. What would cause the number of ohms to increase in a closed circuit? F. Volts increasing and amps increasing. G. Volts decreasing and amps increasing. H. Volts increasing and amps staying the same. J. Volts decreasing and amps staying the same. 32. Which of the following conclusions would be consistent with the relationship between volts, amps and ohms? F. Volts are a ratio of amps to ohms. G. Ohms are a ratio of volts to amps. H. Amps are a ratio of ohms to volts. J. They have no relationship. 29. What is the ratio of volts to amps in Study 1? A. 500 B. 5000 C. 50 D. 5 13
Passage VI Scientists were determining the set of safety standards an oil refinery should use as they refine oil with a sulfuric acid. The mixture of the hydrocarbons of the oil and the acid can be stored in many different ways as it waits for the next step of the refinery process. The best storage standards keep any accidental release of acid and hydrocarbons from being added to the environment around the plant. Experiment 1 The scientists looked first at the pressure and temperature of the mixture in storage. Pressure is measured in psi (pounds per square inch) and the temperature is measure in degrees Fahrenheit. Trial Number Storage Tank Pressure Storage Tank Temperature Percent Recovery Rate 1 55 40 85 2 55 70 72 3 85 40 89 4 85 70 77 Experiment 2 The scientists also wanted to determine if the shape and the size of the fittings for the hoses that connect from the refinery to the storage tank were affecting the amount of acid that was recovered. This experiment was conducted at 40 degrees Fahrenheit and at 85 psi. Trial Number Shape of Fitting Size of Fitting Percent Recovery Rate 5 Flange 1.5 mm 75 6 Flange.1 mm 72 7 Circular 1.5 mm 89 8 Circular.1 mm 80 Experiment 3 The scientists theorized that the amount of acid mixed with the hydrocarbons might also affect the recovery rate, since the hydrocarbon forms a small bubble around the acid, allowing it to carry farther away from the recovery field. Trial Number Ratio of Hydrocarbon to Acid in Percent Percent Recovery Rate 9 30:70 95 10 40:60 85 11 50:50 75 12 60:40 55 14
33. As scientists increased the pressure of the storage tank, the recovery rate A. increased dramatically B. decreased somewhat C. increased somewhat D. decreased dramatically 34. The most effective settings for the storage tank are F. 85 psi and 40 degrees G. 85 psi and 70 degrees H. 55 psi and 40 degrees J. 55 psi and 70 degrees 36. If scientists want to increase the acid recovery rate, they should change the storage tank by: F. Lowering the pressure at which the acid is stored and lowering the temperature. G. Lowering the pressure at which the acid is stored and raising the temperature. H. Raising the pressure at which the acid is stored and raising the temperature. J. Raising the pressure at which the acid is stored and lowering the temperature. 37. The ratio of hydrocarbons to acid that has the least detrimental effect on recovery rate is: A. 60:40 B. 40:60 C. 50:50 D. 30:70 35. Fittings influenced the recovery rate. Which fitting can we assume would create the best possible recovery rate? A. 2 mm circular B. 2 mm flange C..2 mm circular D..2 mm flange 38. Why does the percent ratio of hydrocarbons to acid matter? F. There has to be extra acid to break down the hydrocarbons and form the small bubbles. G. The less acid allows the hydrocarbons to be broken down faster. H. There has to be just enough acid to break down the hydrocarbon without forming small bubbles. J. The more acid allows the hydrocarbons to be broken down faster. 15