Question

Lithium metal has a body centred cubic structure. It's density is 0.53g cm - 3
and its molar mass is 6.94g mol-1. Calculate the edge length of a unit cell of lithium metal

Answer 1

Hey !!

Volume of the crystal, a³ = z × M / d × Na

      = a³ = 2 × 6.94 / 0.53 × 6.023 × 10²³

      = 4.348 × 10²³ cm³

Hope it helps you !!

Answer 2

Answer:Lithium metal has BCC structure , BCC cubic unit cell contains 2 atoms

Value of Z = 2

Density (d) = 0.53 g cm-3

Molar mass = 6.94 g mol-1

Edge length (a) = ?

a3 = Z×Md×NA

a3 = 2×6.940.53×6.022×1023

a3 = 4.348×10−23

a = 0.351×10-7 cm

Therefore , the edge length of unit cell of lithium atom is 0.351×10-7 cm