$A$ metal crystallizes with a $FCC$ lattice, the edge of whose unit cell is $x \text{ pm}$. The diameter of this metal atom would be $\text{pm}$.

Calculate the molar mass of an element having density $7.8 \ g \ cm^{-3}$ that forms a $bcc$ unit cell. $\left[a^3 \cdot N_{A} = 16.2 \ cm^3 \ mol^{-1}\right]$

Calculate the density of an element having molar mass $27 \ g \ mol^{-1}$ that forms $fcc$ unit cell. $[a^3 \cdot N_A = 38.5 \ cm^3 \ mol^{-1}]$ (in $g \ cm^{-3}$)

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

Copper crystallises in a $ccp$ arrangement and the accepted value of the metal ion radius was found to be $1.28 \ \mathring{A}$. Calculate the density of copper in grams per cubic centimetre. (Atomic weight of copper is $63.5 \ g/mol$, $N_A = 6.022 \times 10^{23} \ mol^{-1}$) (in $g/cm^3$)

At $100\, ^\circ C$,copper $(Cu)$ has $FCC$ unit cell structure with cell edge length $x\, \mathring{A}$. What is the approximate density of $Cu$ (in $g\, cm^{-3}$) at this temperature? [Atomic mass of $Cu = 63.55\, u$]