Question

Molecules have ionization energies, just like atoms do. The ionization energy for molecular oxygen, for example, is 1314 kJ/mol. This is the amount of energy required to remove one electron from an O2 molecule, forming an O2+ ion. What is the longest wavelength of light that could ionize an O2 molecule?

Answer 1

91.1835 nm

Step-by-step explanation:

Given that the ionization energy of the oxygen molecule = 1314 kJ/mol

It means that

1 mole of oxygen molecules can be ionized by the energy = 1314 kJ = 1314000 J

1 mole of molecules contains 6.022 × 10²³ atoms

So,

6.022 × 10²³ atoms of oxygen molecules can be ionized by the energy = 1314000 J

1 atom require
`(1314000)/(6.022* 10^(23))\ J` of energy

Energy =
`2.18* 10^(-18)\ J`

Also

`E=\frac {h* c}{\lambda}`

Where,

h is Plank's constant having value
`6.626* 10^(-34)\ Js`

c is the speed of light having value
`3* 10^8\ m/s`

`\lambda` is the wavelength

So,

`\lambda=\frac {h* c}{E}`

`\lambda=(6.626* 10^(-34)* 3* 10^8)/(2.18* 10^(-18))\ m`

`\lambda=91.1835* 10^(-9)}\ m`

Also,

`1\ nm=10^(-9)}\ m`

So, wavelength = 91.1835 nm