Question

The unit of length convenient on the atomic scale is known as an angstrom and is denoted by Å: 1 Å = 10–10 m. The size of a hydrogen atom is about 0.5 Å. What is the total atomic volume in m3 of a mole of hydrogen atoms ?

Answer 1

Given, the size of a hydrogen atom is about 0.5  A o .

The volume of one hydrogen atom is,

V= 4 3 ×π× r 3 = 4 3 ×π× ( 0.5  A o × 10 −10  m 1  A o ) 3 =5.236× 10 −31   m 3

One mole of hydrogen contains 6.023× 10 23 atoms.

So, the total atomic volume of one mole of hydrogen atom is,

V one mole =V×n =5.236× 10 −31   m 3 ×6.023× 10 23 =3.15× 10 −7   m 3 ≅3× 10 −7   m 3

Thus, the volume of one mole of hydrogen atom is ≅3× 10 −7   m 3 .