PNB 2265 Chapter 4: Lab 4 notes
10 Feb 2017
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Sample solution is illuminated from light from a visible light source: range of wavelengths, light is filtered to select monochromatic wavelength (only one, some light is absorbed by sample and some is transmitted through sample. Dependent upon color intensity of sample: detector measures absorbance of light (a) Amount of light absorbed by sample is proportional to concentration of. Beer"s law: linear relationship between the concentration of solute in a solution and solute in sample (analight) the absorbance of electromagnetic radiation (light) I0 = the initial intensity of light: measurement of how strongly a substance absorbs light at a given wavelength intrinsic property of substance, constant value l = optical path length through sample. Units: e = liters/ mole * cm. Dependent on molecular nature of compound analyzed and wavelength of light illuminating the sample ( ) l = cm: c = moles/liter, absorbance is unit less measurement. Some substances may have more than one peak of absorbance.
