chem final 3

26. Sunlight (solar radiation) may be turned directly into electricity using ________ cells. A. fuel B. photovoltaic C. electrolytic D. lead-acid

B. photovoltaic

28. Semiconductors are more effective than metals as converters of solar radiation into electricity because A. it is easier for the atoms of a semiconductor to absorb solar energy and to move from place to place within the solid, thereby conducting electricity. B. the energy contained in sunlight gives the valence electrons in the semiconductor atoms the extra energy they need to "flow" throughout the solid. C. metals melt much too easily under direct sunlight and, as liquids, lose their ability to conduct electricity. D. solar radiation has sufficient energy to knock electrons completely off the metal surface, making it impossible for the electrons to "flow" from atom to atom and conduct electricity.

B. the energy contained in sunlight gives the valence electrons in the semiconductor atoms the extra energy they need to "flow" throughout the solid.

22. Approximately what percentage of the electrical energy generated in the United States is produced from nuclear energy? A. < 2 percent B. 10 percent C. 20 percent D. 50 percent

C. 20 percent

7. If you have 200.0 g of radioisotope with a half-life of 5 days, how much isotope would remain after 15 days? A. 12.5 g B. 13.3 g C. 25.0 g D. 40.0 g

C. 25.0 g

1. The half-life of carbon-14 is 5,730 years. If you started with 100.0 g of carbon-14, how much would remain after 4 half-lives? A. 25.0 g B. 12.5 g C. 6.25 g D. 57.3 g

C. 6.25 g

11. How much energy is equivalent to 1.0 ´ 10¯4 kg of matter? (Speed of light = 3.0 ´ 108 m/s) A. 3.0 ´ 104 J B. 3.0 ´ 107 J C. 9.0 ´ 1012 J D. 9.0 ´ 1015 J

C. 9.0 ´ 1012 J

19. Which is not a benefit associated with nuclear power plants? A. Efficient production of electricity B. Reduction of CO2 in the atmosphere C. Inexpensive to operate D. Helps reduce the levels of acid rain

C. Inexpensive to operate

41. What sort of energy is associated with energy from wind? A. Potential energy B. Thermal energy C. Kinetic energy D. Chemical energy

C. Kinetic energy

31. In a solar cell, semiconductors of the p-type and n-type are placed in contact with each other via a conducting wire. In order to generate an electric current, which of the following must be true? A. An external battery must be attached B. Light shining on the system will cause oxidation to occur C. Light shining on the system must have enough energy to set electrons in motion from the n-type semiconductors to the p-type D. Light shining on the system must have enough energy to set electrons in motion from the p-type semiconductors to the n-type

C. Light shining on the system must have enough energy to set electrons in motion from the n-type semiconductors to the p-type

20. What percentage of a radioactive isotope would remain after three half-lives? A. 6.3 percent B. 12.5 percent C. 25.0 percent D. 50.0 percent

B. 12.5 percent

15. Which of these is not a realistic risk associated with nuclear power plants? A. Release of radioactivity from spent fuel rods B. A nuclear explosion C. A meltdown from loss of coolant D. Thermal pollution of nearby body of water

B. A nuclear explosion

35. In this photovoltaic (solar) cell, the n-type semiconductor is in the region labeled A. A B. B C. C D. D

B. B

5. What type of radiation is given off in this nuclear reaction? 14-14/6-7 A. Alpha B. Beta C. Gamma D. Neutron

B. Beta

6. What type of radiation is given off in this nuclear reaction? 210-206/ 84-82 A. Alpha B. Beta C. Gamma D. Neutron

B. Beta

3. Which naturally occurring radioactive particles are negatively charged? A. Alpha particles B. Beta particles C. Gamma radiation D. Neutrons

B. Beta particles

23. Which example is both a type of nuclear radiation and electromagnetic radiation? A. Microwave radiation B. Gamma radiation C. Alpha rays D. Ultraviolet radiation

B. Gamma radiation

17. Waste created at these power plants must be stored indefinitely. A. Coal-burning plants B. Nuclear plants C. Coal-burning and nuclear plants D. None of these choices are correct

B. Nuclear plants

46. Which type of renewable energy has most commonly been adapted for use on an individual home basis? A. Wind B. Photovoltaic C. Hydroelectric D. Biodiesel

B. Photovoltaic

25. Which of the following fission products released from the Chernobyl reactor is dangerous because it concentrates in bones? A. I-131 B. Sr-90 C. C-14 D. U-238

B. Sr-90

38. Given this diagram, this semiconductor is A. made of pure silicon. B. carrying an extra electron. C. missing an electron. D. excited by a photon.

B. carrying an extra electron.

29. Semiconductors, such as the element silicon, may be used in cells that convert solar radiation to electricity. One of the major difficulties encountered in using silicon is that it A. is one of the rarest of all elements and therefore difficult to find on earth. B. is expensive to produce large quantities of extremely pure silicon. C. quickly evaporates when isolated in a pure state. D. is the most active of all the elements, so it cannot be prepared in a pure state.

B. is expensive to produce large quantities of extremely pure silicon.

10. Which is the balanced equation for the fission of U-235? A. B. C. D.

A.

12. If 1.8 ´ 1014 J is released in a nuclear reaction, how much matter was lost? A. 2.0 ´ 10¯3 kg B. 7.2 ´ 102 kg C. 6.0 ´ 105 kg D. 1.6 ´ 1031 kg

A. 2.0 ´ 10¯3 kg

2. Which naturally occurring radioactive particles are the size of a helium nucleus? A. Alpha particles B. Beta particles C. Gamma radiation D. Neutrons

A. Alpha particles

4. Which naturally occurring radioactive particles are the largest? A. Alpha particles B. Beta particles C. Gamma radiation D. Neutrons

A. Alpha particles

37. What metal is used to dope an n-type semiconductor? A. Arsenic B. Cadmium C. Gallium D. Silicon

A. Arsenic

18. Smokestacks at these plants release sulfur oxides and carbon dioxide into the air. A. Coal-burning plants B. Nuclear plants C. Coal-burning and nuclear plants D. None of these choices are correct

A. Coal-burning plants

42. Which of these locations would be best suited to geothermal energy as a source to operate homes? A. Hawaii B. Oklahoma C. Vermont D. England

A. Hawaii

47. To meet the electricity needs of the entire United States, a solar array the size of __________ would be required. A. New Jersey B. New York City C. Texas D. Nevada

A. New Jersey

49. Which source of renewable energy has seen the greatest growth in the last decade? A. Wind B. Photovoltaic C. Hydroelectric D. Biodiesel

A. Wind

36. Complete the following statement while ignoring any thermodynamic considerations. A candle may be considered a more efficient producer of light than a flashlight because it A. converts chemical energy directly into light. B. produces more heat than a flashlight. C. does not have a battery to recharge or replace. D. may be used in remote locations far from electrical networks or power lines.

A. converts chemical energy directly into light.

40. How is wind energy related to the Sun? A. It has no relation B. Wind turbines need solar panels to operate correctly C. The heat of the Sun drives large-scale movements of air D. Wind turbines only operate during daylight hours

C. The heat of the Sun drives large-scale movements of air

32. Silicon has four electrons in its outer energy level, gallium has three. Adding small amounts of gallium to pure silicon A. destroys the ability of the silicon to act as a semiconductor. B. provides the basis for using the silicon as a fuel cell. C. creates a p-type semiconductor. D. creates an n-type semiconductor.

C. creates a p-type semiconductor

16. Which is not true of radioactive half-life? Radioactive half-life is A. the time required for the level of radioactivity in a sample to be cut in half. B. independent of the amount of radioactive material present. C. increased by heating the isotope. D. independent of the physical or chemical form of the isotope.

C. increased by heating the isotope.

45. Which unit is commonly used by utilities to measure the amount of electrical energy consumed? A. W B. MW C. kWh D. J

C. kWh

9. Fission is the process of creating energy by A. combining small nuclei to form a larger, more stable nucleus. B. combining small nuclei to form a larger, less stable nucleus. C. splitting large nuclei to form smaller, more stable nuclei. D. splitting large nuclei to form smaller, less stable nuclei.

C. splitting large nuclei to form smaller, more stable nuclei.

39. As of 2007, what is the maximum efficiency of a multijunction solar cell? A. 15 percent B. 80 percent C. 22 percent D. 40 percent

D. 40 percent

24. Rank the forms of nuclear radiation from highest to lowest mass. A. Gamma, alpha, beta B. Beta, gamma, alpha C. Alpha, gamma, beta D. Alpha, beta, gamma

D. Alpha, beta, gamma

14. Which feature or process is unique to nuclear power plants when compared to conventional coal-burning power plants? A. Formation of steam B. Smoke stacks C. Steam turbines D. Control rods

D. Control rods

8. In the famous equation E = mc2, the symbols represent A. E = Einstein, m = matter, c = speed of light. B. E = energy, m = mass, c = characteristic of the particle. C. E = Einstein, m = meters, c = conversion. D. E = energy, m = mass, c = speed of light.

D. E = energy, m = mass, c = speed of light.

34. Which argument(s) for the increasing use of solar energy is/are valid? I. Solar cells are becoming cheaper and increasingly more efficient II. The cost of generating electricity from fossil fuels is increasing III. Limited and uncertain supply and the increasing requirements for pollution control are raising the cost of using fossil fuels A. I only B. II only C. I and III only D. I, II and III

D. I, II and III

33. Which increases the efficiency of a photovoltaic or solar cell? I. Replacing crystalline silicon with its non-crystalline form II. Increasing the number of alternating p- and n-type layers of semiconductors III. Decreasing the thickness of each alternating p- and n-type layer of semiconductor A. I and II only B. II and III only C. I and III only D. I, II, and III

D. I, II, and III

50. Which of the following is not an advantage of locating wind turbines off-shore instead of on land? A. The wind blows faster and more uniformly over water B. Land is scare, especially near coastlines C. Large numbers of people live near coastlines and could make use of the energy D. Maintenance costs are lower off-shore

D. Maintenance costs are lower off-shore

48. Which of the following is not seen as an advantage of increasing our use of solar energy? A. It would reduce our dependence on fossil fuels B. Solar energy does not generate air pollution such as nitrogen oxides and sulfur oxides C. Energy from the Sun is abundant D. Production and storage of solar energy is cost-efficient compared to fossil fuels

D. Production and storage of solar energy is cost-efficient compared to fossil fuels

13. Which is a common characteristic of both nuclear and conventional electric power plants? A. Smoke stacks B. Fuel rods C. Control rods D. Steam turbines

D. Steam turbines

21. Which is a known risk associated with nuclear power plants? A. The electricity produced will be radioactive B. The water used to cool the system will become radioactive C. The workers will have higher risks for cancer than the standard population D. The cooling water source can suffer thermal pollution

D. The cooling water source can suffer thermal pollution

43. Which of these locations would be most likely to use electricity generated by hydroelectric power? A. Kentucky B. Russia C. Venezuela D. Washington

D. Washington

30. The "doping" of a semiconductor to improve its performance means A. slightly raising the temperature of a pure semiconductor to improve the ability of its electrons to flow from atom to atom. B. fusing layers of two different pure semiconductors together to give the electrons that absorb the solar radiation characteristics of the electrons of both semiconductors. C. mixing large amounts of a metal with small amounts of a semiconductor so that the metal itself becomes a semiconductor. D. adding small amounts of other elements to the pure semiconductor to change the freedom of electron motion throughout the crystal.

D. adding small amounts of other elements to the pure semiconductor to change the freedom of electron motion throughout the crystal.

27. To date, solar radiation is not a practical source for the production of electricity used to power A. electric highway signs. B. security lighting in parking lots. C. satellites in orbit around the earth. D. fleets of taxis.

D. fleets of taxis.