Gold has a cubic close-packed structure which can be viewed as spheres occupying $74\%$ of the total volume. What is the edge length of the unit cell if the density of gold is $19.3 \ g/cm^3$? $(Au = 197 \ amu)$

Calculate the edge length of a unit cell if a metal having an atomic radius of $170 \ pm$ forms a simple cubic unit cell.

In an orthorhombic crystal system,the values of $a$,$b$,and $c$ are $4.2 \, \mathring{A}$,$8.6 \, \mathring{A}$,and $8.3 \, \mathring{A}$ respectively. Given the molar mass of the solute is $155 \, g \, mol^{-1}$ and the density is $3.3 \, g \, cm^{-3}$,calculate the number of formula units $(Z)$ per unit cell.

$A$ certain element crystallises in a $bcc$ lattice of unit cell edge length $27 \mathring{A}$. If the same element under the same conditions crystallises in the $fcc$ lattice,the edge length of the unit cell in $\mathring{A}$ will be .........
(Round off to the Nearest Integer).
[Assume each lattice point has a single atom]
[Assume $\sqrt{3}=1.73, \sqrt{2}=1.41$]

Calculate the number of atoms in $1 \ g$ of a metal if it forms an $fcc$ crystal structure,given that $\varrho \times a^3 = 1.728 \times 10^{-22} \ g$.

Calculate the number of unit cells in $1 \ cm^3$ of an element if the unit cell edge length is $2.0 \times 10^{-8} \ cm$.