Question

Find the energy released when 2.0 mole of atoms of Hydrogen undergo transition. giving a spectral line of lowest energy in the visible region of its atomic spectra (in KJ)

Answer 1

E = $\frac{-R_H{Z}^2}{n^2}$
$\Delta E=E_3-E_2$
$\Delta E=R_H{Z}^2[\frac{1}{{n_2}^2}-\frac{1}{{n_3}^2}]=R_H{Z}^2[\frac{1}{4}-\frac{1}{9}]$
$\Delta E=1312\times \frac{5}{36}=182.22kJ.mo{l}^{-1}$
For 2 moles, $\Delta =182.22\times 2=364.4kJ$