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Unformatted text preview: CHM 374 Spring 2010 HOMEWORK SET 1 Due Wed., Jan. 20 (in class) Read Chapter 1, particularly Section 1.3, of Understanding Physical Chemistry (UPC) 1. Calculate the energy (in J units) and momentum (in units of kg m/s) of photons with the following colors: a) A blue photon with a wavelength of 400 nm b) A red photon with a wavelength of 700 nm 2. What is the wavelength (in nm) and energy (in J) of an infrared (IR) photon which could exchange energy with molecule that has a vibrational frequency of 1000 cm-1 ? 3. Calculate the energy in kJ/mol units, of ultraviolet (with =250 nm) and infrared ( ~ =1000 cm-1 ) photons, and compare these energies with the energy of a typical covalent bond to explain why it is a good idea to put on an ultraviolet (UV) sun-block when you go to the beach (but it is not so important to use an IR sun-block)? 4. Use the quantization procedure which Bohr suggested in his original (old) theory of atomic line spectra (see p. 25-30 of UPC) to show that this same procedure could be used to predict that line spectra (see p....
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- Spring '10