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. `2.0xx10^(-20) J`
B. `2.2xx10^(-19)J`
C. `2.0xx10^(-19)J`
D. `4.0xx10^(-20)J`

Answer

A

Explanation

(a) Kinetic energy (KE) of molecule = energy absorbed by molecule-bond energy per molecule
`(4.4xx10^(-19))-(4.0xx10^(-19))J=0.4xx10^(-19) J`
KE per atom `=(0.4xx10^(-19))/(2) J = 2.0 xx10^(-10)J`