Question
Tue July 17, 2012 By: Surya Saxena
 

Iodine molecule dissociates into atoms after absorbing light of 4500 angstrom .if 1 quantum of radiation is absorbed by each molecule,calculate the kinetic energy of iodine atoms.(bond energy of iodine molecule=240KJ)

Expert Reply
Sat July 21, 2012

Energy given to Iodine molecule = hc/?

                                            = 6.62 × 10-34 × 3 × 108 / 4500× 10-10

                                             =4.417 × 10-19 J

The total energy provided is calculated by 
E = hc/? = 4.41 x 10-19 J
Energy absorbed by each atom :
E (atom) = 2.205 x 10-19 J

Now Bond Energy of each molecule (B) = 3.98 x  J
So, for each atom 1.99 x 10-19 J 

So now
KE of each atom = E(atom) - B (atom)
                         = 2.15 x 10-19 J
 

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