Posted: January 30th, 2017
1.Name the three kinds of strength used to characterize materials AND give an example of a material that are strong in each of these modes. 2.What kinds of bonding occurs in each of the three materials you listed in question #1? 3.Explain how atoms can be arranged in such a way to create a permanent magnet. 4.Identify 10 objects in your home that use semiconductors. What other kinds of materials with special electrical properties are found in all of these 10 objects? 5.Research the status of magnetically levitated trains like the one now operating in China. How does it operate? How fast might it go? 6.How does a nuclear reactor work? 7.What types of researchers and scientists use carbon-14 radiometric dating? What type of researcher would use the other isotopes such as uranium-238? 8.Use the periodic table to identify the element, its atomic number, mass number and electrical charge of the following:
9.Potassium-40 decays into argon-40 with a half-life of 1.2 billion years. A particular mineral grain is known to have had a million potassium atoms in its crystal structure when it formed. When the grain was ground up, scientists discovered 750,000 atoms of argon-40. When did the grain form? (Hint: Use Figure 12-10 on page 272 to obtain a qualitative estimate). 10.What are the half-lives of the following common isotopes: ◦Carbon-14: ◦Uranium-238: ◦Uranium-235:
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