- Ii Use The Data Given To Confirm That This Sample Is Optically Thin And Calculate The Fraction Of The Light That Is Ab 1 (40.52 KiB) Viewed 38 times
- Ii Use The Data Given To Confirm That This Sample Is Optically Thin And Calculate The Fraction Of The Light That Is Ab 2 (70.16 KiB) Viewed 38 times
- Ii Use The Data Given To Confirm That This Sample Is Optically Thin And Calculate The Fraction Of The Light That Is Ab 3 (70.16 KiB) Viewed 38 times
1. (a) The chlorination of ethane can be initiated by photolysis of Cl2 using UV light. The absorption cross section of Cl₂ at 350 nm is 1.88 x 10-19 cm² (C₂H6 does not absorb at this wavelength). A mixture of Cl2 and C₂H6 was contained in a cylindrical vessel of length 10.0 cm. The number density of Cl2 was 6.54 x 1015 cm-3. The sample was irradiated by a UV lamp which provided a uniform intensity of 12.6 W cm2 at 350 nm at the entrance to the vessel. (i) Explain what is meant by the expressions optically thin and optically thick in this context. (ii) Use the data given to confirm that this sample is optically thin and calculate the fraction of the light that is absorbed. (iii) Express the incident intensity of the light in photons per unit area per unit time. (iv) Hence calculate the rate of absorption of photons per unit volume. h (v) If no other radiative or non-radiative processes compete with photodissociation of Cl2, what is the quantum yield for formation of Cl atoms? Hence calculate the initial rate of Cl production resulting from the absorption of the 350 nm light. 12 1 2