Directions: Choose the best answer for each of the following items.
Questions 1 and 2 are based on the following passage.
Thermite is a mixture of a metal powder (aluminum) and metal oxide (iron oxide). When ignited, the metals in the mixture react to produce a burst of extremely high temperature. Thermite is used to cut or weld steel, as when repairing train tracks.
1. The chemical equation for a thermite reaction is shown. Balance the equation by adding coefficients.
____________________ Al + Fe2O3 → Al2O3 + ____________________ Fe
2. The thermite reaction is an example of which type of reaction?
A. synthesis
B. exothermic
C. endothermic
D. decomposition
3. Which of the following is a property of most metals?
A. soft and brittle
B. form negative ions
C. solid at room temperature
D. high melting and low boiling point
Questions 4 through 6 are based on the following passage.
A student wants to observe the properties of solutions with various amounts of saturation. She uses a common photograph developing chemical, sodium hyposulfite, as the solute and water as the solvent.
A test tube is filled with 2 milliliters of water, and 1 gram of hyposulfite crystals is added to the test tube. The test tube is shaken to dissolve the crystals. The crystals dissolve rapidly, and the solution in the test tube becomes clear.
Two grams of hyposulfite crystals are added to 2 milliliters of water in a test tube. After several minutes of shaking the test tube, the crystals dissolve. The solution is cloudy.
Three grams of hyposulfite crystals are added to 4 milliliters of water in a test tube. The test tube is shaken and the crystals dissolve. The solution in the test tube becomes clear.
Thirty grams of hyposulfite crystals are added to 2 milliliters of water. The mixture is heated to a gentle boil. Then the test tube is placed in a container of cold water until it returns to room temperature. Small crystalline particles are observed in the solution.
4. Which of the following is a possible source of error in the experimental design?
A. using 2 milliliters of water in experiment 1
B. using 30 grams of crystals in experiment 4
C. using 4 milliliters of water in experiment 3
D. using 2 grams of hyposulfite in experiment 2
5. How could the design of the experiment be altered to correct this error?
A. Use 30 milliliters of water in Experiment 4.
B. Do not shake the tube in Experiment 1.
C. Do not heat the water in Experiment 4.
D. Use 2 milliliters of water in Experiment 3.
6. Which type of heat transfer is demonstrated by the boiling mixture in Experiment 4?
A. radiation
B. convection
C. conduction
D. combustion
7. Gamma rays are the most dangerous type of electromagnetic radiation because they
A. transfer the most energy.
B. have the lowest frequency.
C. have the highest wavelength.
D. are not visible to the human eye.
8. A truck is traveling down the highway at a speed of 65 miles per hour. Which other piece of information is needed to determine the truck’s momentum?
A. truck’s mass
B. distance traveled
C. truck’s acceleration
D. amount of travel time
9. A student wants to test how different types of flooring affect the motion of a toy car. Which of the following would be the best design for an experiment?
A. Choose 3 cars with equal masses. Push cars down a ramp onto 3 different types of flooring. Observe the car that traveled the farthest on each type of flooring.
B. Choose 3 cars with different masses. Allow cars to roll down a ramp onto 3 different types of flooring. Observe the car that traveled the farthest on each type of flooring.
C. Choose 3 cars with equal masses. Allow cars to roll down a ramp onto 3 different types of flooring. Observe the distance traveled by each car on each type of flooring.
D. Choose 3 cars with different masses. Push cars down a ramp onto 3 different types of flooring. Observe the distance traveled by each car on each type of flooring.
10. Which of the following tasks is NOT considered work?
A. trying to turn on a stuck water faucet
B. pushing a wheelbarrow over a flat lawn
C. rolling a trash can down a steep driveway
D. dragging a bag of raked leaves behind you