# PS12 - c. What is the volume of the cell in terms of r? d....

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1 Chemistry 2090 Problem Set #12 (last hand-in PS) Due Wednesday (in class), April 27, 2011 Chap 12 Problems: 2, 12, 22, 36, 42, 45, 58, 63, 75, 76, 82, 86, 108 Chap 13 Problems: 5, 20, 28, 32, 46, 51, 66, 71 F2. The hexagonal close-packed cell of Co metal is shown below. In the top (and bottom) of the cell, Co atoms are in contact as shown, and the angles in the top are 60° and 120°; all remaining angles are 90 °. The side edge of the cell is {4(2) 1/2 /(3) 1/2 }r long, as shown, and the top edges are equal in length. top 4 2 3 r = a. How many Co atoms are in the unit cell? b. How many lattice points describe the hexagonal cell?
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Unformatted text preview: c. What is the volume of the cell in terms of r? d. What is the packing efficiency of the cell in percent? e. If the density of Co is 8.90 g/cm 3 , what is the atomic radius of a cobalt atom? f. The following data correspond to elemental cobalt: D (l) = 7.75 g/cm 3 , D (s at 23 C) = 8.90 g/cm 3 , mp = 1768 K, bp = 3200 K, critical pressure and temperature unknown. Generate a phase diagram for Co, labeling the solid, liguid and gas regions, and the melting and boiling points. p T g. If the heat of vaporization of cobalt is 377 KJ/mol, what is its boiling point at 20 atm?...
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## This note was uploaded on 06/10/2011 for the course CHEM 2090 taught by Professor Zax,d during the Spring '07 term at Cornell University (Engineering School).

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