Question

Calculate the density of metal having molar mass $210 \text{ g mol}^{-1}$ that forms simple cubic unit cell. (Given: $a^{3} \cdot N_{A} = 21.5 \text{ cm}^{3} \text{ mol}^{-1}$)}

• A. 9.77 \text{ g cm}^{-3}
• B. 7.15 \text{ g cm}^{-3}
• C. 8.12 \text{ g cm}^{-3}
• D. 6.94 \text{ g cm}^{-3}

Hint:

Always remember the formula for the density of a unit cell: $\rho = \frac{Z \cdot M}{a^3 \cdot N_A}$. Pay attention to the type of unit cell (simple cubic, BCC, FCC) to correctly determine the value of $Z$. Simple cubic: $Z=1$, Body-centered cubic (BCC): $Z=2$, Face-centered cubic (FCC): $Z=4$.

Answer 1

The Correct Option is C