A mixture of argon and mercury vapor used

Question

in advertising signs emits light of wavelength 610 nm.
Calculate the energy change resulting from
the emission of 1.00 mol of photons at this wavelength.
Answer in units of kJ/mol.

Answer 1

Use E=hc/lambda to calculate the energy (in J).

This is the energy of one photon. There are 6.02 x 10^23 particles per mole.

So energy changes is

E x 6.02 x 10^23 J/mole

or

E x 6.02 x 10^20 kJ/mole