If Avogadro's number is `6.06 xx 10^(23)` per gram mole, what is the mass of a molecule of hydrogen in SI units ? Calculate Boltzmann's constant if `R = 8.31 J mol^(-1) K^(-1)`.

Answer

`3.3 xx 10^(-27)kg, 1.37 xx 10^(23) J molecule^(-1)K^(-1)`

Explanation

Mass of one gram mole of hydrogen = 2 gram = `(2//1000)`kg. Therefore, mass of one molecule of hydrogen
`=(2)/(1000 xx 6.06 xx 10^(23)) = 3.3 xx 10^(-27)kg`
Boltzmann constant `k = R//N`
`=8.31//6.06 xx 10^(23)`
`=1.37 xx 10^(23) J "molecule"^(-1)K^(-1)`