Cobalt has a density of 8.9 g/cm3, and the mass of a cobalt atom is 9.79 10-26 kg.?

Question

(a) If the atoms are spherical and tightly packed, what is the volume of a cobalt atom? (Answer needed in metre cube)

(b) What is the distance between the centers of adjacent atoms? (answer needed in metres)

plz help if u know these answers and also to the other question I have I would really appreciate it!

Answer 1

In one cm^3 you will find this amount of atoms.

8.9X 10-3g/cc * 1 atom/9.79 10-26 kg =9.09 e22 atoms

The number of atoms that can be lined in to 1 cm length is

(9.09 e 22)^(1/3)=4.496 e7

If you can get this much in 1 cm then you can do a proportional equation to get the diameter as follows;

1 atom/ x cm=4.496 e7/1 cm

2.224e-8 cm or 2.224e-10 meters for the diameter.

Now use the equation volume of a sphere = 4/3 pi r^3

b) the diameter of the atoms is the distance between adjacent centers.