Spectra of Conjugated Dyes & Beer's Law Overview Getting Started Techniques Procedure FAQ Full Lab Manual Introduction & Goals Chemistry & Background Key Questions Prelab Problems Safety Procedure In Your Write-up Experiments Index ChemLab Home		Using a Spec 20 Spectrometer You will use a Spectronic 20 spectrometer to measure the absorption and transmission spectrum of one of the two conjugated dyes. For more information on the two types of instruments in the lab, click on the following links. Spectrometer: Analog Spectrometer: Digital Using a scanning Spectrometer You will use a scanning spectrometer to measure the absorption spectra of the second conjugated dye and your Koolaid solution. For more information on this instrument, click on the Spectrometer: Scanning link. Making a solution in a volumetric flask Your solution of Koolaid must be made with a precisely known concentration. Calculate the mass of powder needed to make 25 mL of solution at the concentration given on the label. Use an analytical balance to measure the mass of powder as precisely as possible. Transfer the drink mix carefully and quantitatively to a volumetric flask. Rinse the weighing paper with deionized water to make sure all the solid is transferred from the paper to the flask. Rinse the funnel with solvent, to make sure that no material is lost. Add solvent to partially fill the flask and shake it to dissolve the powder completely. When the solid is dissolved completely, you can add solvent to bring the level of the meniscus to the mark on the neck of the flask. See the volumetric flask page for more information about using this piece of glassware. Invert and shake the flask thoroughly, to ensure complete mixing and a uniform solution.
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