Question

A metal has fcc lattice. the edge length of unit cell is 404 pm the density of the metal is 2.72 g cm the moalar mass of metal is

Answer 1

use the formula:
d=ZM÷(a raised power 3)×Na(avagadros no)....

Answer 2

Hey !!

Density , ρ = Z × M / a³ ×  Na × 10⁻³⁰

 ∴ 2.72 = 4 × M / (404)³ × (6.02 × 10²³) × 10⁻³⁰

(OR) M = 2.72 × (404)³ × 6.02 × 10²³ × 10⁻³⁰ / 4

        = 27 g mol⁻¹

Hope it helps you !!