Question

The element crystallizes in a body centred cubic lattice and the edge of unit cell is $0.351nm$. The density is $0.533g/cm3$. What is the atomic weight?

• A. $12.0$
• B. $6.94$
• C. $9.01$
• D. $10.8$

Answer 1

Answer: (B)

$6.94$

Density $d=\frac{Z\times M}{a^3\times N_A}$

$a=0.351nm=3.51\times {10}^{-8}cm$

$d=0.533g/c{m}^3$

$Z=2$

$d=\frac{Z\times M}{a^3\times N_A}$

$M=\frac{d\times a^3\times N_A}{Z}$

$M=\frac{0.533\times (3.51\times {10}^{-8}{)}^3\times 6.023\times {10}^{23}}{2}$

$M=6.94$