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The Chapter12:Numbers42,46,50,52,54,64,66(pages316319) Chapter13:Numbers2,14,18,30,38,48,50,54,66,68,74(pages343346) 42. atoms that make up your body are mostly empty space, and structures such as the chair youre sitting on are composed of atoms that are mostly empty space. So why dont you fall through the chair? 46. If two protons and two neutrons are removed from the nucleus of an oxygen-16 atom, a nucleus of which element remains? 50. Which has more atoms a 1-g sample of carbon-12 or a 1-g sample of carbon-13? Explain 52. Which contributes more to an atoms mass: electrons or protons? Which contributes more to atoms size? 64. With the periodic table as your guide, describe the element selenium, Se? 66. With scanning probe microscopy technology, we see not actual atoms but rather images of them. Explain? Chapter13:Numbers2,14,18,30,38,48,50,54,66,68,74(pages343346) 2. What is the origin of most of the natural radiation we encounter? 14. Why is there more carbon-14 in living bones than in once living ancient bones of the same mass? 18. How is a nuclear reactor similar to a conventional fossil-fuel power plant? How is it different? 30. Consider a radioactive sample with a half-life of one week. How much of the original sample will be left at the end of the second week? The Third week?The fourth week? 38. A pair of protons in an atomic nucleus repel each other but they are also to attracted each other. Explain. 48. Is carbon dating advisable for measuring the age of materials a few years old? How about a few thousand years old? A few million years old? 50. The age of the Dead Sea Scrolls was determined by carbon-14 dating. Could this technique have worked if they have been carved on some tablets? Explain? 54. Why will nuclear fission probably never be used directly for powering automobiles? How could it be used indirectly? 66. Explain how radioactive decay has always warmed the Earth from the inside and how nuclear fusion has always warmed the Earth from the outside? 68. Sustained nuclear fusion has yet to be achieved and remains a hope for abundant future energy. Yet the energy that has always sustained us has been the energy of nuclear fusion? Explain 74. Your friend Paul says that the helium used to inflate balloons is a product of radioactive decay. Your mutual friend Steve says no way. Then theres your friend Alison, fretful about living near a fission power planet. She wishes to get away from the radiations by traveling to the high mountains and sleeping out at night on granite outcroppings. Still another friend, Michele, has journeyed to the mountain foothills to escape the effects of radioactivity altogether. While bathing in the warmth of a natural hot spring, she wonders aloud how the spring gets its heat. What do you tell these friends? ... View Full Document

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