Help! Calculating Light Energy and Such!!?

Question

45. During photosynthesis, chlorophyll-a absorbs light of wavelength 440 nm and emits light of wavelength 670 nm. What is the energy available for photosynthesis from the absorption - emission of a mole of photons?

54. If each atom in one mole of atoms emits a photon of wavelength 5.55x10^3 Å, how much energy is lost? Express the answer in kJ/mol. As a reference point, burning one mole (16g) of CH4 produces 819kJ of heat.

Answer 1

45

I'd say the delta energy dE

dE= E1 - E2

whre E= hv

h - planks constant = 6.623x10^-34 J s

v - frequency of the wave

where v= c/ L  so

L- wave length

c - the speed of light

then

dE= ch ( 1/L1 - 1/L2)

Oh I forgot the 54

54. Again

E= h c/L

total energy

Et= NE or

Et = N h c / L  where

N - the Avogadro's number= 6.022 x 10^+23 atoms/mole