Calculate the number of unit cells in 8.1 g of aluminium, if it crystallises in a face centered cubic structure. ( Atomic mass of `Al = 27 g mol^(-1)` )

Explanation

Given `:`
1 mole of Al = Avogadro's constant `= 6.023 xx 10^(23)`
Mass of aluminium `= 8. 1 g `
Solution `:`
1 mole of aluminium ( Al ) = 27 g
`= 6.02 xx 10^(23) ` atoms
`:.` No. of atoms present in 1g of `Al = (6.02 xx 10^(23))/( 27)`
Face centered cubic unit cell contains 4 atoms.
`:.` No. of unit cells `= ( 6.02 xx 10^(23))/( 27 xx 4) xx 8.1= 4.52 xx 10^(22)`