The number of atoms in 100g of FCC crystal with density = 10g/cm3 and cell edge equal to 200 pm is equal to _____?
d = Z x M/a3 x NA
where, a is edge of unit cell
NA = Avogadro number (6.022 × 1023)
M = Molar mass
Z = number of atoms per unit cell
For fcc, Z = 4
From the given data we can calculate the Molar mass of given substance as:
M = d x a3 x NA /z
Number of atoms = givan mass / molar mass(M) x NA
Putting the vaue of M in above equation we get
Number of moles = given mass x z x NA / d x a3 x NA
Number of atoms = given mass x z / d x a3
putting the values we get:
Number of atoms = 100 g x 4 / 10 gcm-3 x (200 x 10-10 cm)3 = 400 / 80 x 10-24 = 5 x 1024 atoms
where, a is edge of unit cell
NA = Avogadro number (6.022 × 1023)
M = Molar mass
Z = number of atoms per unit cell
For fcc, Z = 4
From the given data we can calculate the Molar mass of given substance as:
M = d x a3 x NA /z
Number of atoms = givan mass / molar mass(M) x NA
Putting the vaue of M in above equation we get
Number of moles = given mass x z x NA / d x a3 x NA
Number of atoms = given mass x z / d x a3
putting the values we get:
Number of atoms = 100 g x 4 / 10 gcm-3 x (200 x 10-10 cm)3 = 400 / 80 x 10-24 = 5 x 1024 atoms