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?
Radius of hydrogen atom, r = 0.5 Å = 0.5 × 10-10 m Volume of hydrogen atom = (4/3) π r3 = (4/3) × (22/7) × (0.5 × 10-10)3 = 0.524 × 10-30 m3 1 mole of hydrogen contains 6.023 × 1023 hydrogen atoms. ∴ Volume of 1 mole of hydrogen atom = 6.023 × 1023 × 0.524 × 10–30 = 3.16 × 10–7 m3
