# Energy Conversion in Fluorescent Minerals

## How much energy in kJ/mol was converted to heat when a fluorescent mineral absorbs black light from a mercury lamp and emits visible light with a wavelength of 520 nm?

The amount of energy in kJ/mol that was converted to heat when a fluorescent mineral absorbs energy with a wavelength of 320 nm can be calculated using Planck's constant, speed of light, and Avogadro's number.

## Answer:

The energy in kJ/mol that was converted to heat is 3.08 × 10-26 kJ/mol.

Fluorescent minerals can absorb energy and re-emit it as visible light, a fascinating phenomenon that can be explained by various scientific principles. In this case, when a fluorescent mineral absorbs black light with a wavelength of 320 nm from a mercury lamp and emits visible light with a wavelength of 520 nm, some of the absorbed energy is converted to heat.

To calculate the amount of energy in kJ/mol that was converted to heat, we can use the formula E = hc/λ, where E is the energy, h is Planck's constant (6.626 × 10^-34 J s), c is the speed of light (3.00 × 10^8 m/s), and λ is the wavelength in meters.

By plugging in the values for h, c, and the absorbed and emitted wavelengths, we arrive at an energy value of 1.85 × 10^-19 J. To convert this energy into kJ/mol, we divide by Avogadro's number (6.022 × 10^23 molecules/mol) and convert to kilojoules.

After the calculations, we find that the amount of energy in kJ/mol that was converted to heat is 3.08 × 10^-26 kJ/mol, showcasing the intriguing energy transformation that occurs in fluorescent minerals.