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# Copper crystallises into a fcc lattice with edge length 3.61 x10 ^ -8 cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm^ -3.

1.15    Copper crystallises into a fcc lattice with edge length $\inline 3.61\times 10^{-8}cm.$ Show that the calculated density is in agreement with its measured value of $\inline 8.92\; g\; cm^{-3}$.

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The relation between density and edge lenght gives :

$Density = \frac{z.M}{a^3.N_A}$

Since it crystallises in fcc lattice, thus z = 4.

Molar mass of copper = 63.546 u.

So,

$Density = \frac{4\times63.546}{(3.61\times10^{-8})^3\times6.022\times10^{23}}\ cm$

$= 8.97\ g\ cm^{-3}$

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