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

Energy given to ` I_2` molecule
` = ( hc )/( lambda) = ( 6. 625 xx 10 ^(-34) xx 3 xx 10^8) /( 4500 xx 10^(-10)) = 4.417 xx 10^(-19) J`
Also energy used for breaking up `I_2` molecule
`(240 xx 10^3 )/( 6.023 xx 10^(23)) = 3 . 984 xx 10^(-19) J`
`therefore` Energy used in imparting kinetic energy to two (I) atoms ` = [ 4.4.17 - 3. 984] xx 10^(-19) J`
`:.` K.E. /iodine atom `= [ ( 4 .417 - 3. 984 ) // 2] xx 10^(-19)`
` =0 . 216 xx 10 J`.