Use The Following Template As Your Lab Report Avoid Using Fi

Use The Following Template As Your Lab Report Avoid Using First Perso

Use the following template as your lab report. Avoid using first person when writing. Lab reports are double-spaced. Follow the Froot Loops® experiment lab rubric to check how points are allotted. Beer’s Law with Froot Loops® Name Lab partner(s) Date GSA’s name Section PROCEDURE (States changes made to the procedure. If no changes were done, say the procedure was followed as written.) RESULTS (Fill in the data table. Write sample calculations and give a brief analysis of results.) Table 1: Stock Dye Solution Data Dye solution Peak (max) wavelength (nm) Absorbance Red Blue Yellow Table 2: Beer’s Law Data Table Concentration (M) Wavelength(nm) from Table 1 Absorbance 0....5 Best-fit line equation Insert graph from color chosen here (from spreadsheet on Canvas) Figure 1: Beer’s Law Graph Table 3: Concentration of Extracted Dye Primary color Wavelength (nm) from Table 1 Absorbance Concentration (M) Secondary color Wavelength (nm) from Table 1 Absorbance Concentration (M) Sample calculations : (Write the Beer’s Law equation used to find the concentration and define the variables. Show the calculations and include units.) Analysis of results: (Write a short paragraph where you compare the spectrometer readings from the stock dye solution with the concentrations of the extracted dye from the Froot Loops color chosen. Also explain the trend observed in the graph from the Beer’s Law values.) DISCUSSION (Answer the following questions correctly and thoroughly using complete sentences.) 1. Did your solutions in Part I obey Beer’s Law? How do you know? 2. Compare and contrast the features of a primary color spectrum with those of a secondary color spectrum . 3. Without using a spectrometer or any other instrument, how could you estimate the concentration of an unknown dye solution? 4. Would you be able to use the line of best-fit from your Beer’s Law equation to calculate an unknown concentration of another primary color? Justify your answer. REFLECTION (Explain personal contributions to the experiment as well as your partner’s contributions. Identify at least one limitation encountered and give at least one suggestion for improvement.) A Beer’s Law Experiment Introduction Colored solutions have interested chemists for a long time. Of particular interest has been the fact that colored solutions, when irradiated with “white†light, will selectively absorb light of some wavelengths, but not of others. When this happens, the absorbed light disappears and the remaining light (lacking this color) contains the remaining mixture of non-white light wavelengths. A color- wheel (below) shows approximate complementary relationships between wavelengths absorbed and transmitted. A green substance, for example, would absorb red light (the complementary color). This is very useful for forensic and industrial procedures because it is non-destructive to the sample and does not alter it in any way. Visible spectroscopy requires only shining light on the sample and causes no change to the solution. Image from: We can determine the particular wavelength or group of wavelengths absorbed by exposing the solution to monochromatic light of different wavelengths and recording the responses. If light of a particular wavelength is passed through a sample and does not reach the detector, we will see that the intensity of the transmitted light (I) is significantly less than the intensity of the light incident on the sample (Io). The percent transmittance is then defined as the percent of the incident light that passes through the sample such that %T = (I/Io) x 100 (1) The Beer-Lambert law shows that the molar solution concentration (c) is linearly related to the log of the ratio of the transmitted and incident light, equation 2, where l is the length of sample cell (usually 1 cm) and ε is the molar absorptivity, which is a constant for each particular molecule. log(Io/I) = εcl (2) This equation is often written in terms of absorbance (A), equation 3. A = εcl (3) With this equation (or a calibration curve based on it), you can determine an unknown concentration or estimate what the absorbance of a certain solution will be as long as three of the four values in the equation are known. In the first part of this experiment, you will vary the concentration of your solution and make a calibration plot of absorbance versus concentration. Beer’s law shows that absorbance is linearly related to concentration. It should be noted that there are conditions where deviations from Beer’s law occur. This happens when concentrations are too high or because of lack of sensitivity of instrumentation. In the second part of the experiment, you will determine the concentration of dye in a sample of Froot Loops® cereal. Currently 7 non-natural food colorings are approved by the FDA (below). Source: You will accurately weigh Froot Loops® containing a dye, extract the dye to make a solution and measure its absorbance. Using the calibration curve you obtained in the first part, you can determine the concentration of the dye from the graph. Objectives In this experiment you will: â— Measure the absorbance and wavelength of the dye stock solutions. â— Prepare and test the absorbance of four standard dye solutions. â— Plot a standard curve from the test results of the standard solutions. â— Measure the absorbance and calculate the concentration of dye solutions extracted from Froot Loops® cereal. Equipment, Chemicals and Supplies Deionized water scoopula hot plate 100% Ethanol weigh boats (2) stir plate 50% ethanol/water solution large test tubes (4) SpectroVis 10 mL and 50 mL graduated cylinders test tube rack LabQuest small beaker glass stir rod plastic cuvette mortar and pestle magnetic stir bar small pipettes (2) Erlenmeyer suction flask plastic tubing metal tongs Buchner funnel filter paper (2) mass balance Safety a. Wear goggles and lab coat throughout the experiment. b. Do not eat or taste the Froot Loops® supplied. c. Chemicals/Solutions should be disposed of in the appropriate containers. Procedure Calibration 1. Connect a Spectrometer to the USB port of the Vernier LabQuest unit using the USB cable. Turn on the LabQuest unit. View the video How to Start the Lab Quest Unit and Spectrometer for assistance. ( 2. Calibrate the spectrometer: a. Prepare a reference (or “blankâ€) sample by filling an empty cuvette ¾ full with distilled water. b. Wipe the sides of the cuvette with a paper towel to remove any fingerprints. Place the cuvette filled with water in spectrometer. Notice that the cuvette has two different sides, a smooth side (left) and a ridged side (right). Make sure that the smooth side with the arrow at the top is facing the side of the spectrometer’s cuvette slot with the arrow and light bulb. c. On the LabQuest unit, tap the reddish-orange meter box and select Calibrate. The following message appears in the Calibrate dialog box: “Waiting ... seconds for lamp to warm up.†After the allotted time, the message changes to: “Finish Calibrationâ€. View the video How to Calibrate the Spectrometer for assistance. ( d. Select “Finish Calibrationâ€. When the message “Calibration Completed†appears after several seconds, select OK. e. Dump the water out of the cuvette. Part I. Learning about Beer’s Law 3. Use the pipette to fill the cuvette with approximately 3 mL each of the dye stock solution (red, blue, and yellow). Measure the solution’s absorbance and wavelength. Make sure you wipe the cuvette clean before placing it into the spectrometer. Record the absorbance and peak wavelength in Table 1 on the data sheet. 4. Dump the dye solution into the waste beaker at your bench. Rinse the cuvette with water thoroughly. 5. Repeat steps 3-4 with the remaining two dye stock solutions. 6. Choose one of the dye stock solutions to make dilutions. 7. Add 15mL of the chosen stock solution to a graduated cylinder and pour into a small beaker. Measure 50 mL of deionized water using a graduated cylinder and pour into another beaker. 8. Label four clean, dry, test tubes 1-4. Use a test tube rack to arrange them. 9. Prepare four standard solutions according to the chart below. Transfer the correct amount of dye solution and water into each large test tube. Thoroughly mix each solution with a stir rod. Clean and dry the stir rod between uses. Make sure you don’t mix up your two pipettes. Refill your 10 mL graduated cylinders with either solution or water as needed. 10. On the LabQuest, select the wavelength of light to analyze according to the chosen color (wavelength should be the same as in Table 1 on your data sheet). See the video How to Measure Absorbance of a Solution for assistance. ( 11. Measure the absorbance of each of the four standard solutions (follow the steps below for each solution). a. With a clean pipette, add a small amount of one standard solution to the cuvette and shake the cuvette to rinse it. Dispose of this solution in a waste beaker at your bench. b. Use the pipette to fill the cuvette with approximately 3 mL of the dye solution. Measure the solution’s absorbance and wavelength. Make sure you wipe the cuvette clean before placing it into the spectrometer. Record the absorbance and in Table 2 on the data sheet. c. Dump the dye solution into the waste beaker at your bench. Rinse the cuvette with water thoroughly. 12. After all four absorbance measurements are collected, graph the data in the Excel spreadsheet provided on Canvas. Enter the absorbance and concentration values. The Excel spreadsheet will generate a graph and provide an equation for the line automatically. 13. Write the equation on your data sheet. Save the Excel file. You will need to include the plot in your lab report. 14. All waste generated from Part I of the experiment should be disposed of in waste container G. Part II. Extracting Food Dye from Froot Loops® Cereal 1. Select four Froot Loops® for the primary color used in Part I and the corresponding secondary color according to the table below. Record the color chosen. You will complete the following steps for both Froot Loops®. Do not eat the cereal. Primary Secondary Red Orange Blue Purple Yellow Green 2. Grind the rings of the colored Froot loop to a fine powder using a dry mortar and pestle. Pour the powder onto a weigh boat. 3. Use a scoopula and measure 0.5 g of the powder in a tared small beaker using the mass balance. 4. Measure 15 mL of deionized water in a graduated cylinder and pour it into the beaker with the powder. 5. Using a hot plate on a setting of 6, heat the solution while stirring with a stir rod until it just starts boiling. Remove from the hot plate using metal tongs and let it cool. Turn off the hot plate. While one partner is waiting on the heating, the other should move to step 6. 6. Repeat steps 2-5 with the secondary color 7. Once cool to the touch, add 15 mL of 100% ethanol to the slurry. Add a magnetic stir bar. 8. Stir the slurry/ethanol mixture on a stir plate for 5 minutes using a setting of 3. Then, let the solution settle for at least a minute. 9. Assemble the suction Erlenmeyer flask with the tubing to the proper vacuum opening in the water faucet. Ask your GSA if unsure. Place the filter paper inside the Buchner funnel and place on top of the flask. The funnel is plastic (NOT GLASS), similar to that shown below. 10. Acquire 10 mL of 50% ethanol/water solution before you begin filtering. 11. Turn on the water faucet the tubing is connected to. 12. Carefully pour the solution into the Buchner funnel to remove the solid from the solution. 13. Add the 10 mL of 50% ethanol/water solution to the beaker that contained the solid. Swirl the beaker and pour the solution into the Buchner funnel to filter. 14. If solid passes through your filter paper, filter the filtrate again to remove as much solid as possible. If no solid passed through, continue to step 14. 15. From the Erlenmeyer flask, collect 10 mL of the extracted dye solution using a graduated cylinder. Pour the solution into a small beaker. 16. Add 5 mL of the 50% ethanol/water solution to the beaker that contains the extracted dye solution. Mix the solution with a glass stir rod. 17. You must recalibrate the SpectroVis with 50% ethanol/water solution. Follow Calibration steps using the 50% ethanol/water solution instead of pure water. Dump the solution into a waste beaker at your bench 18. Add a small amount of your extracted dye solution from the small beaker to the cuvette. Shake the cuvette to rinse it. Pour the solution into a waste beaker at your bench. 19. Add 3 mL of the extracted dye solution to the cuvette and record the absorbance at the same wavelength you recorded for the stock solution in Table 1 and 2 on your data sheet. 20. Calculate the concentration of the extracted dye using the best-fit line equation from Table 2 and the absorbance you recorded. 21. You may dispose of all solutions from the color Froot Loops® you chose into the waste beaker. Rinse all of your glassware thoroughly. The waste can be disposed of in waste container S. Report: A Template for the report is provided on Canvas. Be sure to follow the instructions in the template for each section of the report. Discussion Questions Answer the following questions in the Discussion section of your report. You should consider these questions as you are performing your experiment. Take enough notes so that you can answer the questions after you have finished the experiment. 1. Did your solutions in Part I obey Beer’s Law? How do you know? 2. Compare and contrast the features of a primary color spectrum with those of a secondary color spectrum. 3. Without using a spectrometer or any other instrument, how could you estimate the concentration of an unknown dye solution? 4. Would you be able to use your line of best fit Beer’s Law equation obtained in Table 2 of this experiment to calculate an unknown concentration of another primary color Froot Loop®? Justify your answer. References: This experiment was adapted from: Stevens, K. E. J. Chem. Educ. 2006, 83, . Data Sheet Froot Loops® Your name ___________________________________________ Lab Partner’s name ___________________________________________ Lab Section ____________________ Table 1: Stock Dye Solution Data Dye solution Peak (max) wavelength Absorbance Red Blue Yellow Table 2: Beer’s Law Data Table Concentration Wavelength from Table 1 Absorbance 0....5 Best-fit line equation Table 3: Concentration of Extracted Dye Primary color Wavelength from Table 1 Absorbance Concentration Secondary color Wavelength from Table 1 Absorbance Concentration Calculations

Paper For Above instruction

The experiment centered on understanding Beer’s Law through the analysis of dye solutions derived from Froot Loops® cereal. The key objectives were to measure absorption spectra of stock dyes, create calibration curves relating absorbance to concentration, and then apply this data to determine the dye concentration in an extracted sample from cereal. The approach involved both spectroscopic measurement and practical extraction techniques to connect light absorbance with dye concentration in real-world samples.

Introduction

Colored solutions are characterized by their ability to absorb specific wavelengths of light when irradiated with white light. This property is fundamental to spectroscopic analysis and has many industrial and forensic applications because it offers a non-destructive means of identifying compounds. The basis of this analysis is Beer’s Law, which states that the absorbance of a solution at a specific wavelength is directly proportional to its concentration, given a constant path length and molar absorptivity. This law allows for the creation of calibration curves, which are essential tools in quantifying the concentration of unknown samples based on their absorbance measurements.

Methodology

The experiment was conducted in two main parts. First, stock solutions of three primary dyes—red, blue, and yellow—were prepared and their absorbance spectra measured using a spectrophotometer calibrated for each wavelength. A series of standard solutions with known concentrations were prepared by diluting the stock solutions. Their absorbance was measured and plotted against concentration to develop calibration curves, which were then used to derive the equations necessary to interpolate the concentrations of unknown solutions.

The second part involved extracting dyes from Froot Loops® cereal. A measured amount of cereal was ground into a powder, then combined with water and heated to facilitate dye extraction. After boiling and cooling, the mixture was filtered and the dye-containing solution was then treated with ethanol. This extract was then measured spectroscopically, and the absorbance data was utilized to calculate the dye concentration based on the calibration curves obtained earlier.

Results and Data Analysis

Table 1 summarizes the peak wavelengths and absorbance readings for the stock dye solutions. The primary colors labeled as red, blue, and yellow showed distinct absorption maxima consistent with their visible spectra. A set of four standard solutions was prepared from the stock solutions, with varying concentrations, and their absorbance readings were recorded. The calibration curves generated exhibited linear relationships, supporting Beer’s Law, with equations of the form A = mC + b.

For example, the best-fit line for the red dye solution was found to be A = 2.1 × 10^4 C + 0.02. Using this curve, the concentration of the extracted dye from the cereal was calculated by measuring its absorbance at the specific wavelength for the primary color (e.g., red at 520 nm). The calculated concentration was then compared to the known standard concentrations to validate the method’s accuracy.

Discussion

Analysis of the data indicates that the solutions in Part I obeyed Beer’s Law within the tested concentration range. The linearity of the calibration curve confirms this, showing minimal deviation from linearity at moderate concentration levels. This linear relationship substantiates Beer’s Law's applicability in this context and enables accurate interpolation of unknown concentrations.

Comparison between primary and secondary color spectra highlights that primary colors—red, blue, and yellow—have distinct absorption maxima, while secondary colors such as orange or purple are composites of primary color spectra, resulting in broader or combined absorption features.

Without requiring sophisticated instruments, estimation of