Question

The edge length of bcc type of unit cell of an element is 400 pm. Calculate the density of unit cell. (Molar mass of an element = 100 g mol^-1)

Options

• 2.144 g cm^-3

• 10.378 g cm^-3

• 7.289 g cm^-3

• 5.189 g cm^-3

Answer 1

5.189 g cm^-3 

Explanation:

Edge length of bee type cell = 400 pm

M = 100 g mol^-1

Density (ρ) = `("n" xx "M")/("a"^3 xx "N"_"A")`

`= (2 xx 100)/((400 xx 10^-10)^3 xx 6.022 xx 10
^23)`

`= (200)/(64 xx 10^-24 xx 6.022 xx 10^23)`

= 5.189 g cm^-3