The iodine molecule dissociates into atoms after absorbing light of 4500Å. If one quantum of radiat is absorbed by each molecule, calculate the kinetic energy of iodine atoms (Bond energy I_(2) = 240 kJ mol^(-1))

The iodine molecule dissociates into atoms after absorbing light of 45

1.	The iodine molecule dissociates into atoms after absorbing light of 4500Å. If one quantum of radiat is absorbed by each molecule, calculate the kinetic energy of iodine atoms (Bond energy I_(2) = 240 kJ mol^(-1))
Answer» Solution :Bond energy PER molecule of `I_(2) = (240 xx 1000J)/(6.022 xx 10^(23)) = 3.985 xx 10^(-19)J` Energy absorbed `= (HC)/(lamda) = ((6.626 xx 10^(-34) Js) (3 xx 10^(8) ms^(-1)))/(4500 xx 10^(-10)m) = 4.417 xx 10^(-19)J` The difference of energy absorbed and energy used for dissociation of bond in `I_(2)` gives the KINETIC energy one `I_(2)` molecule. `:.` K.E. of one `I_(2)` molecule `= (4.417 xx 10^(-19) - 3.985 xx 10^(-19)) J = 4.32 xx 10^(-20)J` `:.` K.E. of one iodine atom `= (4.32 xx 10^(-20))/(2) J= 2.16 xx 10^(-20)J`