How many unit cells are present in a cube-shaped ideal crystal of $NaCl$ of mass $1.00 \ g$?

An element with an atomic mass of $96 \, amu$ has a unit cell density of $10.3 \, g/cm^3$ and an edge length of $314 \, pm$. The crystal structure is of the type:

Ferrous oxide has a cubic structure and each edge of the unit cell is $5.0 \ \mathring{A}$. Assuming the density of the oxide is $4.0 \ g \ cm^{-3}$,calculate the number of $Fe^{2+}$ and $O^{2-}$ ions present in each unit cell ($M_w$ of $FeO = 72 \ g/mol$).

Calculate the number of unit cells in $0.4 \ g$ of metal if the product of density and volume of the unit cell is $1.2 \times 10^{-22} \ g$.

Aluminium crystallises in a face-centred cubic structure, its atomic radius is $125 \text{ pm}$. What is the edge length of the unit cell (in $\text{pm}$)?

In a $NaCl$ crystal,the distance between $Na^+$ and $Cl^-$ ions is $2.814 \ \overset{\circ}{A}$ and the density of the crystal is $2.167 \ g/cm^3$. Calculate the value of Avogadro's number $(N_A)$.