Question

Calculate the density of pbs crystal (fcc) if the edge lenght of its unit cell is 500 Pm

Answer 1

Answer:

1. Given: PbS forms FCC structure. a = 500 pm = 5 × 10⁻⁸ cm. NA = 6.022 × 10²³ Atomic mass of Pb = 207.2 and S = 32.

2. To Find: The density (d) of PbS crystal.

3. Calculation: - Molar mass of PbS = 207.2 + 32 = 239.2 gm. - For FCC, z = 4. - V = a³ = (5 × 10⁻⁸)³ ...

⇒ d = 12.71 gm/cm³

- So, the density of PbS is 12.71 gm/cm³.

Hope it's help