QUIZ2-2008key

QUIZ2-2008key - T Polymers typically contain both covalent...

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PRINT NAME ________________________ INTRODUCTION TO MATERIAL SCIENCE MSE-150 QUIZ 2 I PLEDGE MY HONOR THAT I HAVE NEITHER GIVEN OR RECEIVED AID ON THIS EXAMINATION. I FURTHER PLEDGE THAT, IF I HAVE REASON TO SUSPECT THAT THE CODE HAS BEEN VIOLATED, I HAVE TAKEN OR WILL TAKE ACTION AS OUTLINED IN THE CODE. SIGNATURE _________________________ (1 point each) True or False T Ionic bonding is a non-directional primary bond resulting from electrostatic forces. F Covalent bonding is a directional primary bond resulting from sharing of delocalized valence electrons. F Cations are typically larger than anions. F The atomic packing factor (APF) of the face centered cubic (FCC) structure is less than the APF of the hexagonal close packed structure (HCP). F As the difference in the electronegativities between the elements in a ceramic compound decreases the bond character is more ionic than covalent.
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Unformatted text preview: T Polymers typically contain both covalent and secondary bonding. T The non-directional nature of the metallic bond results in crystals with high coordination numbers. (1 point each) Label the following as characteristics of strong bonds ( S ) or weak bonds ( W ). W low melting point S short bond length W low hardness S small thermal expansion coefficient W low elastic modulus (3 points) What are the coordination numbers (number of nearest neighbors) for FCC, HCP, and body centered cubic (BCC) crystal structures? FCC 12 HCP 12 BCC 8 (2 points) How many atoms are contained inside of the unit cell for FCC and BCC crystals? FCC 4 atoms BCC 2 atoms (3 points) Calculate the atomic radii for copper (FCC with a = 0.361 nm). Use the correct number of significant figures for the correct answer. a) 0.1565 nm b) 0.157 nm c) 0.128 nm d) 0.1276 nm...
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