Question

The number of atoms in 100 grams of fcc crystal with density

Answer 1

Explanation:

Solution :

d=Z×M/a3×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 geicen data we can calculate the molar mass of given substance as :

m=d×a3×NA/z

Number of atoms = given mass / molar mass (M) ×NA

Putting the value of M in above equation we get,

Number of moles = given mass ×z×NA/d×a3×NA

Number of atoms = given mass ×z/d×a3

Putting the values we get:

Number of atoms =100g×4/10gcm−3×(100×10−10cm)3=400/100×1024

=4×1024atoms

Answer 2

Answer:

)

Solution :

d=Z×M/a3×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 geicen data we can calculate the molar mass of given substance as :

m=d×a3×NA/z

Number of atoms = given mass / molar mass (M) ×NA

Putting the value of M in above equation we get,

Number of moles = given mass ×z×NA/d×a3×NA

Number of atoms = given mass ×z/d×a3

Putting the values we get:

Number of atoms =100g×4/10gcm−3×(100×10−10cm)3=400/100×1024

=4×1024atoms