Question

C_sB_r, crystallises in a body centred cubic lattice. The unit cell edge length is 436.6 pm. Given that the atomic mass of Cs = 133 a. m. u and that of Br = 80 a. m. u and Avogadro's number being 6.02 × 1023 mol^–1, the density of Cs Br is:- .

पर्याय

• 4.25 g/cm³

• 42.5 g/cm³

• 0.425 g/cm³

• 8.25 g/cm³

Answer 1

8.25 g/cm³ 

Explanation:

Density = `(Z xx M)/(a^3 xx N_A)`

Given Z = Two formula unit of CsBr in 1 cubic unit = 2 and edge length, a = 436.6 pm = 436.6 × 10^–1 cm.

Molecular weight of CsBr = 133 + 80 = 213 g/mol.

Upon substituting the values in the above density equation:

Density = `(2 xx 213)/((436.6 xx 10^-10)^3 xx 6.022 xx 10^23)` = 8.25 g/cm³