An element crystallizes in an FCC lattice with an edge length of . If exactly of this element contai — Solid State Chemistry Question

💡 Solution & Explanation

The given sample contains $24\times10^{23}$ atoms, i.e. approximately $4$ moles, so the molar mass is $200/4=50\text{ g mol}^{-1}$. For FCC, $Z=4$. With $a=200\text{ pm}=2\times10^{-8}\text{ cm}$, $\rho=\frac{ZM}{N_Aa^3}=\frac{4\times50}{6.0\times10^{23}\times(2\times10^{-8})^3}\approx41.66\text{ g/cm}^3$.