How can this graph be used to identify the concentration of FDC Blue 1 Food Dye

# How can this graph be used to identify the

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2. How can this graph be used to identify the concentration of FD&C Blue 1 Food Dye in an "unknown" solution whose transmittance has been measured spectroscopically? Explain in terms of Beer's law and provide an example of how the analysis would be carried out. 3. Consult the ingredients label for a blue-colored sports drink or other consumer beverage. Identify the dyes that are present and explain whether the beverage can be analyzed using the calibration curve above. 1. Use the formula for the best fit line on the calibration curve to determine the concentration (micromolar, μM) of the dye in the beverage.
2. Calculate the mass of dye (in milligrams) contained in one liter of the beverage. The molar mass of FD&C Blue 1 is 793 g/mol. Discussion Questions: 1. Calculate the value of %T for an absorbance of 1.5. Use the result to speculate why absorbance measurements >1 are less accurate. For Questions 2-4, consider the following: Spectrophotometeric studies can be conducted on any colored compound. The transition metal group of the periodic table exhibits a wide array of different colored compounds. In aqueous solutions, Cu 2+ ions will bond to six water molecules forming a complex ion, [Cu(H 2 O) 6 ] 2+ , which is a light blue color. The water molecules can be displaced by ammonia molecules, which are which are stronger Lewis bases than water. The complex ion tetraaminecopper(II) contains four ammonia molecules covalently bonded to a copper (II) ion. The appearance of the intense dark blue-violet color of the [Cu(NH 3 ) 4 ] 2+ ion is often used as a positive test to verify the presence of the complex ions. 2. Write a balanced chemical equation for the reaction of copper (II) sulfate and ammonia to produce tetraaminecopper(II) sulfate. 3. [Cu(NH 3 ) 4 ] 2+ solutions exhibit a deep blue-violet color. Would you expect the wavelength of maximum absorbance (λ max ) for [Cu(NH 3 ) 4 ] 2+ to be greater than or less than the λ max for [Cu(H 2 O) 6 ] 2+ ? 4. The electron transitions responsible for the colors of transition metal ions involve d d transitions. Why are zinc ions colorless in aqueous solution? Conclusion/ Analysis: Write 1 paragraph that includes the following: 1) What is the purpose of this lab? 2) How is a calibration curve useful for identifying the concentration of an unknown solution? 3) How is Beer’s Law applied in this investigation? 4) Include an error analysis, how can the results be improved?

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