Chapter 9, Problem 111E

Excessive exposure to sunlight increases the risk of skin cancer because some of the photons have enough energy to break chemical bonds in biological molecules. These bonds require approximately 250−800 kj/mol of energy to break. The energy of a single photon is given by $E=hc/\lambda$

where E is the energy of the photon in j, h is Planck’s constant $\left(6.626\times {10}^{-31}\text{J}\text{.s}\right)$, and c is the speed of light $\left(3.00\times {10}^8\text{m}/\text{s}\right).$

Determine which kinds of light contain enough energy to break chemical bonds in biological molecules by calculating the total energy in 1 mol of photons for light of each wavelength

a. infrared light (1500nm)

b. visible light (500 nm)

c. ultraviolet light (150 nm)