wavelenght in “nm”
1 Answer
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The ionization energy of hydrogen is 1312 kJ/mol. The energy required to ionize a single hydrogen atom is this quantity divided by Avagadro’s number (the number of particles in a mole):
(1.312*10^6 J/mol)/(6.022*10^23 atoms/mol) =
2.179*10^-18 J/atom
The energy of a photon is related to its wavelength by:
E = h*c/wavelength
where c is the speed of light in a vacuum = 2.998*10^8 m/s
h is Planck’s constant = 6.626*10^-34 (kg*m^2)/s
Solving for the wavelength of a photon that has enough energy to ionize hydrogen:
wavelength = (2.998*10^8 m/s)*(6.626*10^-34 (kg*m^2)/s)/(2.179*10^-18 J)
wavelength = 9.118*10^-8 m = 91.18 nm
