Experiment 6 Determination of the calibration curve of potassium permanganate at 570 and 540nm

Experiment 6
Determination of the calibration curve of potassium permanganate at 570 and 540nm
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Theory
When matter interacts with an energy source (heat, sound, electricity, light, etc.) some of the energy can be absorbed, causing the particles to be elevated to different energy levels. In some cases, the particles can be excited totally out of the original chemical system holding them in place. Under certain conditions, though, the amount of energy absorbed can be controlled, and information about the chemical system can be obtained. This is the case in absorption spectroscopy.
If a beam of light shining is monitored through a sample containing a substance that can absorb one of the beam s wavelengths, a plot of the amount of light absorbed versus the wavelength is obtained. This plot is known as an absorption spectrum, and shows which particular wavelengths of light a chemical species can absorb.
A primary use of absorption spectroscopy in its applicability to quantitative measurements. This is a function of how much light is absorbed, and how that relates to the amount of the absorber present in the sample. The following derivation presents the basics of this relationship.
When a light beam of a certain wavelength (?) and initial intensity (I0) is passed through an absorbing sample contained in a spectrophotometer cell, the intensity of the light beam transmitted through the sample (It).
The fraction of light Absorbance is defined as the following: