Chemistry
posted by Kyle .
Calculate the energy in kJ/mol of a mol of photons in the ultraviolet region of the electromagnetic spectrum that has a wavelength of 2.88 × 107 m. Express answer in scientific notation.
I got 4.16 * 10^8
but the correct answer is supposed to be 4.16 * 10^2.

You must have just punched in a wrong number.
E = (hc/wavelength)*6.02E23
E = (6.626E34*3E8/2.88E7)*6.02E23 in Joules.
Then divide by 1000 to convert to kJ and round to 3 places. I get 415.5 kJ which I would round to 416 kJ. 
Oh okay. Yeah I did convert wrong. Thank you.

Why did you multiply by Avogadro's Number???