## Chemistry and Chemical Reactivity (9th Edition)

a) $c=\lambda\times\nu$ $\lambda=2.998\times10^8\ m/s\div 850 \times10^{6}\ 1/s=0.35\ m$ b) Per photon: $E=h\times\nu$ $E=6.626\times10^{-34}\ J.s\times 850\times10^{6}\ 1/s=5.63\times10^{-25}\ J$ Per mole: $E=5.63\times10^{-25}\ J\times6.022\times10^{23}\ 1/mol=0.34\ J/mol$ c) $c=\lambda\times\nu$ $\nu=2.998\times10^8\ m/s\div 420 \times10^{-9}\ m=7.14\times10^{14}\ 1/s$ Per photon: $E=h\times\nu$ $E=6.626\times10^{-34}\ J.s\times 7.14\times10^{14}\ 1/s=4.73\times10^{-19}\ J$ Per mole: $E=4.73\times10^{-19}\ J\times6.022\times10^{23}\ 1/mol=284.8\ kJ/mol$ Which is much bigger than the cell phone signals. d) $284.8\times10^3/0.34=840,000$ times greater energy per mole of violet light.