## Chemistry and Chemical Reactivity (9th Edition)

Energy of one photon = $4.0\times10^{-19}J$ Energy of 1 mole of photons = $2.4\times10^{5}J$
Energy of one photon, E = hν = $\frac{hc}{λ}$ h = $6.626\times10^{-34}Js$ c = $2.997925\times10^{8}ms^{-1}$ λ = $5.0\times10^{2}$ nm = $5.0\times10^{2}\times10^{-9}m$ = $5.0\times10^{-7}m$ E = $\frac{6.626\times10^{-34}Js\times2.997925\times10^{8}ms^{-1}}{5.0\times10^{-7}m}$ = $4.0\times10^{-19}J$ Energy of 1 mole of photons = $4.0\times10^{-19}J\times\frac{6.022\times10^{23}}{1 mole}$ = $2.4\times10^{5}J/mol$