In this worksheet, we will practice calculating molecular rotational and vibrational energies, atomic equilibrium separations, and dissociation energies.

**Q2: **

Find the equilibrium separation distance between the Na^{+} and F^{−} ions in an NaF crystal.
Use a value of 41.99 g/mol
for the molar mass of NaF and use a value of
2.56 g/cm^{3}
for the density of an NaF crystal.

**Q3: **

The separation between hydrogen atoms in a H_{2} molecule
is about 0.075 nm.
Determine the characteristic energy of rotation in eV.
Use a value of Js
for the value of the Reduced Planck Constant, and a value of
931.5 MeV/c^{2} for the value of the unified atomic mass unit.

- A eV
- B eV
- C eV
- D eV
- E eV

**Q4: **

The crystal structure of caesium iodide is body-centered cubic. A ion occupies a cubic volume of , where is the equilibrium separation of ions in the crystal. What is the distance of a ion to its “nearest neighbor” ion if ?

**Q5: **

A diatomic F_{2} molecule with an equilibrium separation of 0.14 nm is in the state.

What is the energy of the molecule?

- A eV
- B eV
- C eV
- D eV
- E eV

How much energy is radiated in a transition from a to a state?

- A eV
- B eV
- C eV
- D eV
- E eV

**Q6: **

An H_{2} molecule with an equilibrium separation distance of 0.0750 nm can have various rotational energy states.

Determine the rotational energy of the state.

Determine the rotational energy of the state.

- A eV
- B eV
- C eV
- D eV
- E eV

Determine the rotational energy of the state.

- A eV
- B eV
- C eV
- D eV
- E eV

**Q7: **

A molecule oscillates at a frequency of 88 THz. What is the difference between its adjacent energy levels?

**Q8: **

The separation between nitrogen atoms in an N molecule is 0.11 nm. Determine the characteristic energy of rotation in electron volts. Use a value of 14 u for the atomic mass of N.

- A eV
- B eV
- C eV
- D eV
- E eV

**Q9: **

The potential energy of a crystal is eV per ion pair. Find the dissociation energy for three moles of the crystal.

- A J
- B J
- C J
- D J
- E J