Question

35.5
Samplo Problem 2 The amount of energy released when 1 x 10atoms of chlorine in vapour
state are converted to CI ions according to the equation,
Cl(g) + e - CI-(g) is 57.86 x 10-10 J.
Calculate the electron gain enthalpy of chlorine atom in terms of kJ mol- and eV per atom.
walanced when 1 x 1010 atoms of chlorine in vapour state are converted to C1-​

Answer 1

Given :

Number of chlorine atoms = 1×10¹⁰ atoms

Energy released from the reaction = 57.86×10⁻¹⁰ J

To Find :

The electron gain enthalpy of chlorine atom

The eV per atom of chlorine

Solution :

• The amount of energy released when 1 mole of chlorine atoms are converted to Cl⁻ ions is known as electron gain enthalpy

                $\Delta_{eg}H=\frac{-57.86\times 10^{-10}\times 6\times10^{23}}{10^{10}}$

                $\Delta_{eg}H=-347.16\times 10^{3}kJ/mol$

                $\Delta_{eg}H=-347.16kJ/mol$

The electron gain enthalpy of chlorine atom is -3.48kJ/mol.

• We know that, 1eV/atom = 96.49 kJ/mol

                $\Delta_{eg} H \:in \:eV = \frac{-347.16}{96.49}$

                $\Delta_{eg}H = -3.5978 eV/atom$

The electron gain enthalpy in eV/atom is 3.5978 eV/atom.

Answer 2

answer = -3.58 ev/atom