Copper (atomic mass = 63. 5 u) has fee lattice with edge length of `x Å`The approximate density of copper in
`g cm ^(-3) is ((y)/( x ^(3))).` Find the value of y (Avogadro's constant `= 6. 0 xx 10 ^(23), ` Atomic weight of `Cu = 63 . 5 u`)

Answer

`423.33`

Explanation

For fee unit cell, Z = 4
Edge length `= a = x Å=x xx 10 ^(8) cm`
`M = 63.5 g mol ^(-1)`
Density `= ( Z xx M )/( a ^(3) xx N _(A)) g cm ^(-3)`
`= ( 4 xx 63.5 g mol ^(-1))/( ( 10 ^(-8) xx x cm ) ^(3) xx 6. 0 xx 10 ^(23) mol ^(-1))= (423 . 33)/(x ^(3)) gcm ^(-3)`
`therefore` Density of copper `= ( 423 . 33)/(x ^(3)) gcm ^(-3)`
` therefore ` Value of .y. is `423.33.`