Homework #7

#1-6 (p.204)

1. Allotropes are different forms of an element that each have distinctly different physical or chemical properties. 
2. Oxygen and silicon are allotropes.
3. a. The properties of graphite are that is it black, a conductor, and leaves a black mark on paper. The diamond is colorless, glass-like, and is very hard. The coal is powdery, and round. b. They can all be different because they have different atomic arrangements. c. The prices are based on the rarity of the atomic arrangements. 
4. Engineered materials are processed while natural materials remain untouched.
5. Ceramics have low reactivity and have durability at high temperatures. The disadvantage is that ceramics are brittle. 
6. Polyethylene can be tailored to be soft and pliable. Optical fibers can replace copper wires in phone data transmutation lines.