Question

4. A metallic element has cubic lattice. Each edge of unit cell is 3.0 Å. The density of metal is 8.5 g/cc. How many unit cells will be present in 15 g of the metal? ​

Answer 1

Answer:

Here is the solution

Explanation:

Let n is the no. of the unit cell present in 50 gm of element

d

metal

=

N

A

×a

3

a×At w.t

⇒8.5 g/cc=

6.023×10

23

×(3×10

−8

cm)

3

1×At. wt.

At. wt.=138.23 g.

∵ No. of unit cell in 138.23 gm=N

A

∴ 1g ______

138.23

N

A

∴ 50g _____

138.23

50

×6.023×10

23

=2.178×10

23

.