## Chemistry and Chemical Reactivity (9th Edition)

Visible light is in the range: 400-700 nm, so the first two are ultraviolet and the last is in the visible spectrum. The one with 285.2 nm is the most energetic because of the smaller wavelength (higher frequency). $c=\lambda\times\nu$ $\nu=2.998\times10^8\ m/s\div 285.2 \times10^{-9}\ m=10.51\times10^{14}\ 1/s$ Per photon: $E=h\times\nu$ $E=6.626\times10^{-34}\ J.s\times 10.51\times10^{14}\ 1/s=6.97\times10^{-19}\ J$ Per mole: $E=6.97\times10^{-19}\ J\times6.022\times10^{23}\ 1/mol=419.4\ kJ/mol$