How much energy is released (in kj) when 1.00 g of h atoms emit a photon of wavelength 656 nm?

We can calculate energy by using following equation:

E = hc / λ

h=6.626 x10 ⁻³⁴Js

c=3x10 ⁸ms⁻¹

λ=656nm = 656x10 ⁻⁹m

1 gram of hydrogen atom is = 1 mol of hydrogen and it emits photons = 6.023x1023 photon

Energy of one photon (E) = (6.626x10 ⁻³⁴ x 3x10⁸) / (656x10⁻⁹m)

Energy of one mole photon (E) = (6.023x10 ²³ x 6.626x10⁻³⁴ x 3x10⁸) / (656x10⁻⁹m)

1.82 x10 ⁵J = 182 kj