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 $4.0\times 10^{-19} J$The kinetic energy of the molecule per atom will be

• A. $2.0\times 10^{-20} J$
• B. $2.2\times 10^{-19} J$
• C. $2.0\times 10^{-19} J$
• D. $4.0\times 10^{-20} J$

Answer 1

Answer: (A)

Kinetic energy (KE) of molecule $=$ energy absorbed by molecule $- $ bond energy per molecule
$=\left(4.4 \times 10^{-19}\right)-\left(4.0 \times 10^{-19}\right) J $
$=0.4 \times 10^{-19} J$
KE per atom $=\frac{0.4 \times 10^{-19}}{2} J $
$=2.0 \times 10^{-20} J$