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=6.626x10⁻³⁴Js

c=3x10⁸ms⁻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) = (6.023x10²³ x 6.626x10⁻³⁴ x 3x10⁸) / (656x10⁻⁹m)

1.82x10⁵J = 182 kj

pure substance: iron,copper

impure substance: water,charcoal

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance