Homework 3 Solution

# Homework 3 Solution - MEEN 222-502 Fall 2008 Homework #3...

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MEEN 222-502 Fall 2008 Homework #3 Due: 17 October 2008 at the beginning of class 1. Callister 4.2 Determination of the number of vacancies per cubic meter in gold at 900°C (1173 K) requires the utilization of Equations 4.1 and 4.2 as follows: 3 24 3 18 5 3 23 Au Au A m 10 3.52 cm 10 3.52 K)(1173K) eV/atom 10 (8.62 m 0.98eV/ato exp 196.9g/mol ) (18.63g/cm atoms/mol) 10 (6.023 exp exp × = × = × × = = = kT Q A N kT Q N N v v v ρ 2. Callister 4.3 Upon examination of Equation 4.1, all parameters besides Q v are given except N , the total number of atomic sites. However, N is related to the density, ( ρ ), Avogadro's number ( N A ), and the atomic weight ( A ) according to Equation 4.2 as 3 28 3 23 Pb A atoms/m 10 5.30 107.9g/mol ) (9.5g/cm atoms/mol) 10 (6.023 × = × = = Pb A N N Now, taking natural logarithms of both sides of Equation 4.1, kT Q N N v v = ln ln and, after some algebraic manipulation m 1.10eV/ato m 10 5.30 m 10 3.60 274K)ln K)(800 eV/atom 10 (8.62 ln 3 28 3 23 5 = × × + ° × = = N N kT Q v v

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MEEN 222-502 Fall 2008 3. Callister 4.7 In order to compute composition, in atom percent, of a 92.5 wt% Ag-7.5 wt% Cu alloy, we
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## This note was uploaded on 06/24/2009 for the course MEEN 222 taught by Professor Radovic during the Fall '08 term at Texas A&M.

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Homework 3 Solution - MEEN 222-502 Fall 2008 Homework #3...

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