The energy absorbed by each molecule (A2) of a substance is 4.4 10-19 J and bond energy per molecule is 4.0 10-19 J. The kinetic energy of the molecule per atom will be
- 2.2 10-19 J
- 2.0 10-19 J
- 4.0 10-20 J
- 2.0 10-20 J
Answer
(4) 2.0 10-20 J
Solution
Part of the absorbed energy breaks the bond, and the rest appears as kinetic energy of the two atoms.
⇒ Kinetic energy per molecule = 4.4 10-19 - 4.0 10-19
= 0.4 10-19 J
∵ A2 2A, the energy is shared by two atoms,
∴ kinetic energy per atom = 0.4 10-192
= 2.0 10-20 J
Answer: (4)