The energy absorbed by each molecule `(A_2)` of a substance is `4.4 xx 10^-19 J` and bond energy per molecule is `4.0 xx 10^-19 J`. The kinetic energy of the molecule per atom will be.

Options

A. `2.2 xx 10^(-19)J`
B. `2.0 xx 10^(-19)J`
C. `4.0 xx 10^(-20)J`
D. `2.0 xx 10^(-20)J`

Answer

D

Explanation

Extra enegry available si equally divided between the two departing atoms of the `A_(2)` molecule and appears as the kinetic enegry. Thus, kinetic enegry per atom
`=(("Enegry absorbed pr molecule")-("Bond energy per moelcule"))/(2)`
`=((4.4xx10^(-19)J)-(4.0xx10^(-19)J))/(2)`
`= (0.4xx10^(-19)J)/(2) = 0.2 xx 10^(-19)J`
`=2.0 xx 10^(-20)J`