(a) Gold has the face-centered cubic structure, and the unit
cell edge length is 4.08 Ã…
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Au-Au distance is = 4.08/1.414 = 2.88 Ã…
In a hexagonal array of gold atoms with this interatomic
spacing, the surface area per atom is
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(2.88 Ã…)^2 x 0.866 = 7.2 Ã…^2
the area per mole of Au surface atoms on the (111) crystal face
is 4.3*10^4 m^2
multiply this area by the surface energy
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(4.3*10^4)*(1.5J/mol)(1kJ/1000J) = 65 kJ per mole of Au surface
atoms
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= 65 kJ/334 kJ x 100% = 19 %
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