Sunday, July 17, 2011
2SDS #7-13, p. 204
7) What is an alloy?
An alloy is a solid combination of atoms of two or more metals.
*Alloys also include some well-defined compounds (having a constant, definite ration of metallic atoms).
8) Give examples of two alloys you use regularly (Hint: see Table 2.7, page 194.)
-Steel: steel is mainly composed of iron and carbon, and it us used to make automobile and airplane parts, kitchen utensils, plumbing fixtures, and architectural design.
-14-carat gold: 14-carat gold is made of gold, copper, and silver, and is used to make beautiful jewelry.
9) What nonmetal is a component of both steel and stainless steel? (Hint: see Table 2.7, page 194.)
Carbon, C, is a component of both steel and stainless steel.
10) Give the formula, use, and an important physical property of an alloy that is also a well-defined compound.
Chromium-platinum alloy:
Formula: Cr3Pt
Use: basis of some commercial razor blade edges.
Physical property: very hard
11) Describe the periodic table location of elements that behave as semiconductors.
Elements that behave as semiconductors are located on the break between metals and nonmetals--metalloids. This characteristic is logical, for metals are known to be conductive, and nonmetals are not.
12) List three elements commonly used for doping semiconductors.
Four elements commonly used for doping semiconductors include phosphorus (P), arsenic (Ar), aluminum (Al), and gallium (Ga).
13) What is the primary use of the products of semiconductor technology?
The primary use of the products of semiconductor technology is the allowance for computers to process digital information. Semiconductor devices include transistors and integrated circuits used in computers and other electronics.
It is the property of the steel alloy to be hardened after heat treatment and cooling. In this process the metal transforms from an austenite to a martensite at a particular temperature condition. All the low steel alloys show good hardenability.
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