Question

What is the wavelength of photons that have molar energy of 479 (kJ)/(mol)?

Answer 1

Solution:

The energy of 1 photon is:

$E=\frac{E_m}{N_A}=\frac{4.79×10^5 J/mol}{6.022×10^{23} mol^{-1}}=7.95×10^{-19} J$

The energy of a photon is related to the wavelength as:

$E=\frac{h×c}{\lambda}$

Therefore:

$\lambda=\frac{h×c}{E}=\frac{6.626×10^{-34} J⋅s \,\,×\,\,3×10^8 m/s}{7.95×10^{-19} J}=2.5×10^{-7}m=250 nm$

Answer: 250 nm.