EXP 11- Lab report.docx - Sara Amini Chemistry 400 Experiment 11 Colorimetric Analysis Unknown Green A 2 I Title Colorimetric Analysis II Purpose The

EXP 11- Lab report.docx - Sara Amini Chemistry 400...

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Sara AminiChemistry 40004/19/2016Experiment 11Colorimetric AnalysisUnknown: Green A
2I TitleColorimetric AnalysisII PurposeThe purposes of this experiment are to relate wavelengths of electromagnetic radiations to color, to assess absorption and transmission properties of solutions to determine an appropriatewavelength for a colorimetric analysis, and to quantitatively analyze an unknown solution to determine its concentration.III Theory1. A turbid sample is a liquid sample that is cloudy, opaque, or thick with suspended matter; the particles that are the reason for the cloudiness of these samples are not visible by the naked eye so we can’t see them but they exist and they can absorb light. The spectrometer we are using works with non-turbid samples. The problem with turbid samples is that when the light is trying to go through the particles in the sample, the particles absorb the light and so the value we get forabsorbance will be a bigger number because the spectrometer detects less light so it reads it as more absorbance.2. first by using a red dye solution that has a standard concentration and a Spectronic, we find theabsorbance of different wavelengths (in 5nm increments) and we graph the absorbance vs. wavelength. Then, we find the peaks of our graph and then we dilute our standard red dye solution 5 times with different amounts of red dye solution in a volumetric flask and we find the absorbance of the solutions in the wavelength that had the largest amount of absorbance in our absorbance vs. wavelength graph (the same thing we did in this experiment). We graph the absorbance vs. concentration and by using the equation of the linear trend line, we find the

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