HW2 ENME382 S10 Section0201

# HW2 ENME382 S10 Section0201 - 3 and a unit cell of cubic...

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ENME 382 Section 0201 Homework #2 Due in class 12 Feb. 2010 1. (Callister 3.3) Molybdenum has a BCC crystal structure, an atomic radius of 0.1363 nm, and an atomic weight of 95.94 g/mol. Compute its theoretical density and compare it with the experimental value found inside the front cover. 2. (Callister 3.6) Using atomic weight, crystal structure, and atomic radius data tabulated inside the front cover, compute the theoretical densities of aluminum, nickel, magnesium, and tungsten, and then compare these values with the measured densities listed in this same table. The c/a ratio for magnesium is 1.624. 3. (Callister 3.10) Show that the minimum cation-to-anion radius ratio for a coordination number of 4 is 0.225. 4. (Callister 3.12) On the basis of ionic charge and ionic radii, predict crystal structures for the following materials: (a) CaO (b) KBr. Justify your selections. 5. (Callister 3.17) A hypothetical AX type of ceramic material is known to have a density of 2.10 g/cm
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Unformatted text preview: 3 and a unit cell of cubic symmetry with a cell edge length of 0.57 nm. The atomic weights of the A and X elements are 28.5 and 30.0 g/mol, respectively. On the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende? Justify your choice(s). Study questions: Note: These are additional questions to help guide you as you read and study. They will not be collected or graded. Callister 3.15 Iron oxide (FeO) has the rock salt crystal structure and a density of 5.70 g/cm 3 . (a) Determine the unit cell edge length. (b) How does this result compare with the edge length as determined from the radii in Table 3.4, assuming that the Fe 2+ and O 2– ions just touch each other along the edges? Callister 3.14 Compute the atomic packing factor for cesium chloride using the ionic radii in Table 3.4 and assuming that the ions touch along the cube diagonals...
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## This note was uploaded on 11/28/2010 for the course ENME 250 taught by Professor Shang during the Spring '10 term at Maryland.

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