An iodine molecule dissociates into atom after absorbing light of wavelength `4500`Å. If quantum of radiation is absorbed by each molecule calculate the kinetic energy of iodine (Bond energy of `I_(2)` is `240`` kJ mol^(-1))`

Explanation

Bond energy per molecule of `I_(2)= (240 xx 1000)/(6.022 xx 10^(23))J= 3.984 xx 10^(-19)J`
Energy absorbed `=(hc)/(lamda)`
`=(6.626 xx 10^(-34) xx 3 xx 10^(8))/(4500 xx 10^(10))= 4.417 xx 10^(-19)J`
`therefore` KE of one `I_(2)` molecule `=4.417 xx 10^(-19)- 3.984 xx 10^(-19)J = 4.33 xx 10^(-20)J`
KE of one I atom `=(4.33 xx 10^(-20))/(2)= 2.165 xx 10^(-20)J`