How much energy is needed to dissociate 0.05% of hydrogen gas occupyin

1.	How much energy is needed to dissociate 0.05% of hydrogen gas occupying a volume of 5.6 litres under S.T.P? The binding energy of a hydrogen molecule is 4.75 eV.
Answer» As S.T.P., 22.4 litre of hydrogen contains 6.023 x 10²³ molecules 5.6 litres of hydrogen contains, (6.023 x 10²³)/(22.4) x 5.6 = 1.50575 x 10²³ molecules Number of molecules in 0.05% of hydrogen = 1.50575 x 10²³ x 0.05/100 = 7.52875 x 10¹⁹ Total energy required to dissociate the molecules = 7.52975 x 10¹⁹ x B.E = 7.52875 x 10¹⁹ x 4.75 eV = 3.576 x 10²⁰ eV = 3.576 x 10²⁰ x 1.6 x 10^-19 J = 57.22 J

How much energy is needed to dissociate 0.05% of hydrogen gas occupying a volume of 5.6 litres under S.T.P? The binding energy of a hydrogen molecule is 4.75 eV.

Answer»

As S.T.P., 22.4 litre of hydrogen contains

6.023 x 10²³ molecules

5.6 litres of hydrogen contains,

(6.023 x 10²³)/(22.4) x 5.6

= 1.50575 x 10²³ molecules

Number of molecules in 0.05% of hydrogen

= 1.50575 x 10²³ x 0.05/100 = 7.52875 x 10¹⁹

Total energy required to dissociate the molecules

= 7.52975 x 10¹⁹ x B.E

= 7.52875 x 10¹⁹ x 4.75 eV = 3.576 x 10²⁰ eV

= 3.576 x 10²⁰ x 1.6 x 10^-19 J = 57.22 J