Question

What is the the energy (in kJ/mol of photons) of infrared radiation that has a wavelength of 26.23 micrometers? The speed of light is 3.00x108 m/s and Planck's constant is 6.626x10-34 J*s.

Answer 1

we have:

wavelength = 26.23*10^-6 m = 2.623*10^-5 m

Find energy of 1 photon first

we have below equation to be used:

Energy = Planck constant*speed of light/wavelength

=(6.626*10^-34 J.s)*(3.00*10^8 m/s)/(2.623*10^-5 m)

= 7.578*10^-21 J

This is energy of 1 photon

Energy of 1 mol = energy of 1 photon * Avogadro's number

= 7.578*10^-21*6.022*10^23 J/mol

= 4.564*10^3 J/mol

= 4.564 KJ/mol

Answer: 4.56 KJ/mol