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Question
The unit of length convenient on the atomic scale is known as an angstrom and is denoted by `Å: 1Å = 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?
Solution
Radius of hydrogen atom, r = 0.5 Å= 0.5 × 10–10 m
Volume of hydrogen atom = `4/3pir^3`
`= 4/3xx22/7xx(0.5xx10^(-10))^3`
=`0.524 xx 10^(-31) m^3`
According to Avagadro’s hypothesis, 1 mole of hydrogen contains 6.023 × 1023 hydrogen atoms.
∴ Volume of 1 mole of hydrogen atoms = NV1
= 6.023 × 1023 × 0.524 × 10–31
= 3.152 × 10–7 m3
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