Question

The energy absorbed by each molecule ($A_2$ of a substance is $4.4\times {10}^{-19}J$ and bond energy per molecule is $4\times {10}^{-19}J$. The kinetic energy of the molecule per atom will be:

• A. $2.2\times {10}^{-19}J$
• B. $2\times {10}^{-19}J$
• C. $4\times {10}^{-20}J$
• D. $2\times {10}^{-20}J$

Answer 1

Answer: (D)

$2\times {10}^{-20}J$

We know that,

$K.E.peratom=\frac{energyabsorbed-bondenergy}{no.ofatomsinthemolecules}$

Given: Molecule is $A_2$ (diatomic)

Energy absorbed $=4.4\times {10}^{-19}J$

Bond energy $=4\times {10}^{-19}J$

Therefore,

$K.E.peratom=\frac{(4.4\times {10}^{-19})-(4\times {10}^{-19})}{2}=\frac{0.4\times {10}^{-19}}{2}=2\times {10}^{-20}J$

Hence, this is the required result.