WebLecture: Electromagnetic Radiation and Photons
Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 6: Sections 1-3.
6.1 Electromagnetic radiation (EM) is light, and light is a wave. The fundamental relationship of all waves is described by speed of wave = frequency * wavelength.
6.2 The energy carried by a single photon of light depends on the frequency (which in turn depends on the speed and wavelength): E = h*frequency = h * speed/wavelength, where h is Planck's constant.
6.3 When electrons change energy states and move between orbitals around an atom, they emit or absorb light with energy equal to the change. Bohr related the change to the energy level by the Rydberg constant, R. Electrons in the ground state have the lowest amount of energy possible. Electrons in excited states have absorbed the precise amount of energy required to make the jump to their excited state.
c = λ * ν
E = h * ν
1/wavelength = R (1/n22 - 1/n12)
E = hcR (1/n2) for any energy level n
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Homework problems: See your Moodle assignment!
Working with your teacher and classmates, design a set of standard concentrations of iodine to act as a reference, and propose method to calibrate concentrations of iodine solution matching your standards. You will use the standards you create to measure the change in concentration during timed reactions of oxalate and iodine conducted under different amounts of light. You will need to identify the materials required for your solutions, and a set of useful concentrations, and describe how you will generate each concentration level.
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