Item 36 has not been slated for public release in 2011.

Transcription

1 S Use the power-plant diagrams and information below to answer questions Power Plants 35. Which describes a chemical change and a physical change that take place during the production of electricity in the coal-fired power plant (Figure 1)? S Lake Intake Figure 1: Coal-Fired Power Plant Coal Supply Stack Conveyor Belt Turbine Generator Steam Line Long- Distance Power Lines Boiler Cooling Water Figure 2: Hydroelectric Power Plant Generator Turbine Condenser Long-Distance Power Lines Diagrams Courtesy of Tennessee Valley Authority 116; 8S0053PSAXA0008B An electric power plant in Toledo, Ohio, is powered by coal (see Figure 1). The coal is Form E SP06 (1) burned to boil water and produce steam. The steam turns a turbine, which causes the generator to produce electricity. River The power plant in Belleville, West Virginia, is hydroelectric (see Figure 2). Water from the lake behind the dam falls on the turbine blades. The turbine turns, which causes the generator to produce electricity. 289; 8S0053PSXXX0000X A. The coal moving along the conveyor belt is a chemical change. The coal burning to give off heat and carbon dioxide gas is a physical change. B. The coal burning to give off heat and carbon dioxide gas is a chemical change. The boiling water turning to steam is a physical change. C. The boiling water turning to steam is a chemical change. The steam turning the turbine is a physical change. D. The steam turning the turbine is a chemical change. The turbine running the generator to produce electricity is a physical change. Item 36 has not been slated for public release in The hydroelectric plant (Figure 2) uses a renewable energy resource. Which statement describes why this resource is considered renewable? A. Heated water turns the turbine. The used water flows upstream back directly into the lake and may be used again right away. B. Falling water turns the turbine. The used water flows upstream back directly into the lake and may be used again right away. C. Heated water turns the turbine. The water is returned to the river downstream, so it may continue in the water cycle. D. Falling water turns the turbine. The water is returned to the river downstream, so it may continue in the water cycle. 6162; 8S0053PSCXC0009D

2 41. In any physical or chemical process, what two quantities are always conserved? A. matter and total energy B. light and acoustic energy C. density and thermal energy D. gravity and potential energy 5444; 8S0000PSDXR0727A Form F SP08 (8)

3 Properties of Substances A scientist measures out 15 ml each of baking soda, salt, sugar, iron filings, and corn starch. She runs a series of procedures and records her results in the table below. The first column in the table indicates the procedure. The remaining columns indicate her results for each substance. Procedure Baking Soda Salt Sugar Iron Filings Corn Starch Measure Mass Measure Volume 19 g 21 g 18 g 118 g 8 g 15 ml 15 ml 15 ml 15 ml 15 ml 42. According to the information in the table, what comparison can the scientist make about the densities of sugar and corn starch? A. Sugar is more dense than corn starch. B. Corn starch is more dense than sugar. C. Sugar and corn starch have the same density. D. Both sugar and cornstarch are more dense than salt. 8926; 8S0193PSAXC0002A FT Form F SP06 (33) S 44. What two changes does sugar undergo when heated in a spoon over a flame? A. two physical changes B. two chemical changes C. a chemical change and then a physical change D. a physical change and then a chemical change 8927; 8S0193PSAXC0003D FT Form F SP06 (34) Heat in Spoon Over Flame Add 3 Drops of Vinegar Mix With Iodine Solution 621 8S0193PSXXX0000X No Change No Change Fizzes and Melts; Then Burns and Turns Black No Change No Reaction at First; Next Day, Rust Had Formed No Reaction at First; Next Day, Rust Had Formed Burns Turns Black or Dark Purple 43. The scientist observes the rust on the sample of iron filings and dries the sample thoroughly. The scientist weighs the entire sample and finds that it has more mass than the original 118 grams. What explains this increase in mass? A. The sample gained mass during drying. B. The sample gained mass during a physical change. C. The sample gained mass during a change of state. D. The sample gained mass during a chemical change. 9646; 8S0193PSAXA0008D

4 S7. A student studying rock densities needs to measure the volume of a small rock sample to the nearest milliliter (ml). The student knows that the rock sample has a volum of at least 5 ml. Which tool should the student use to get the most accurate measure of the volume of water displaced by the rock? A. 100 ml 80 ml 60 ml 40 ml 50 ml B. 25 ml C. 25 ml 20 ml 15 ml 10 ml 5 ml 10 ml D. 5 ml 52; 8S0000SIAXD0129C Form B SP07 (18) 0 ml

5 S26. The following steps describe the process of generating electricity by burning coal in a power plant: 1. The coal fire converts liquid water to steam. 2. The steam rotates fanlike blades of a mechanical turbine. 3. The shaft of the turbine spins an electric generator. 4. The electric power is delivered to the consumer over long-distance power lines. Which energy transformation occurs during this process? A. Nuclear energy of the steam is converted to thermal energy of the turbine. B. Mechanical energy from the turbine is converted to electric energy in the generator. C. Electric energy from the generator is converted to chemical energy in the power lines. D. Chemical energy from the generator is converted to electric energy in the power lines. 135; 8S0000PSDXR0227B

6 Baking Soda and Vinegar Reaction Students perform a chemistry experiment by mixing baking soda with vinegar. They mix 4 grams of baking soda with 50 grams of vinegar in a 6-gram plastic cup as shown below. The cup is left uncovered. The students record the mass and temperature of the mixture every 5 seconds. They continue these observations until 10 seconds after they see the mixture stop bubbling. Their data are shown in the table below. 30. Which graphs show the trends in the mass (M) and temperature (T) change during the baking soda and vinegar reaction shown in the diagram? M T A. (seconds) Mass (grams) Temperature (degrees Celsius) B. M T M S31. The data in the table show the temperature of the cup-baking soda-vinegar system. The temperature of the surrounding air was not measured. Assuming that the total amount of energy remains constant, what conclusion about energy transfer does the temperature data support? A. Thermal energy was lost from the surrounding air and the system. B. Thermal energy was gained by the system and the surrounding air. C. Thermal energy was transferred from the surrounding air to the system. 32. The data show that the mass of the cup and its contents decreases while the mixture is bubbling. In your Answer Document, explain why the mass of the cup and its contents at 25 seconds is less than the initial total mass of the cup, baking soda and vinegar. Include in your answer a valid scientific reason on which you based your explanation. (2 points) C. D. M T T D. Thermal energy was transferred from the system to the surrounding air. 0320; 8S0247PSDXC0004D

7 Density Experiment The two graduated cylinders pictured can hold the same amount of water and use the same scale. A student measures the masses of two metal balls. One ball is made of aluminum and the other ball is made of lead. The student adds 50 ml of water to each graduated cylinder and then drops one metal ball into each graduated cylinder. 100 ml 100 ml 50 ml 50 ml Aluminum Lead 296 8S0060PSXXX0000X 3. Which tool did the student use to measure the mass of each metal ball? A. ruler B. timer C. balance D. graduated cylinder S0060SIAXR0006C 4. The student includes the sentence below in the write-up of this investigation. The lead ball has a measured mass of 113 grams. Which kind of scientific statement is this sentence? A. inference B. prediction C. explanation D. observation 5. The teacher asks the student to use the information she collected to compare the density of the two metal balls. The mass of the lead ball is 113 grams and the mass of the aluminum ball is 27 grams. What can the student infer about the density of these metal balls based on this investigation? A. The density of both metal balls is the same. B. The density of both metal balls is less than the density of the water. C. The density of the lead ball is less than the density of the aluminum ball. D. The density of the lead ball is greater than the density of the aluminum ball. S 6. In repeating the investigation, the student accidentally drops and steps on the lead ball. This action changes its shape from a sphere to an egg-shaped solid. The lead ball is placed back into the graduated cylinder. In your Answer Document, predict what effect, if any, this change has on the amount of water displaced by the lead ball. Explain your prediction. (2 points) S0060PSAXD0003S

8 15. The table below lists the densities of several materials. Material Density (g/ml) Limestone 2.70 Magnesium 1.74 Sulfur 2.07 Water 1.00 Wax 0.95 Which material will float in water? A. limestone B. magnesium C. sulfur D. wax 6459

9 16. Students do an investigation on the reaction of baking soda with vinegar. They create a data table to record the mass (grams) and temperature (degrees Celsius) of the mixture every 5 seconds. Several pieces of data are missing from the table (seconds) Mass (grams) Temperature (degrees Celsius) In your Answer Document, give one example of how the incomplete data make it difficult for the students to draw conclusions about the changes that occur when baking soda reacts with vinegar. Explain how the incomplete data will affect the ability of other students to reproduce the experiment. (2 points)