Question

The amount of energy released when 1 x 10¹⁰ atoms of chlorine in vapour state are converted to Cl^- ions according to the equation.

Cl(g) + e^- → Cl^- (g) is 57.86 × 10^-10 J

Calculate the electron gain enthalpy of chlorine atom in terms of kJ mol^-1 and eV per atom.

Answer 1

Given

CI(g) + e⁻ → CI⁻ (g) is 57.86 × 10⁻¹⁰J

(1 x 10¹⁰ atom)

\(\therefore\) Electron gain enthalpy of chlorine i.e. the amount of energy released when 1 mole (6.023 x 10²³) atoms of chlorine are converted into CI^- ions according to the above equation will be

= \(\frac{57.86\times10^{-10}}{1\times10^{10}}\) x 6.023 x 10²³

= -348.49 x 10³ J mol^-1

= -348.49 kJ mol-1 . 

1 eV/atom = 96.49 kJ mol^-1

Electron gain enthalpy of chlorine = -\(\frac{348.49}{96.49}\)

= -3.61 eV/atom