PROCEDURE A. ABSORBANCE SPECTRA 1. Obtain three cuvettes. Add-2mL of the following samples to them: red dye, blue dye, yellow dye. 2. Obtain a spectrum for each dye according to the provided directions (water is the blank). 3. For each of the three dyes (red, yellow, and blue) record the wavelength for the largest peak in the visible range (380 nm to 750 nm), Record this in the data table below. Save the red dye for part B. 4. Identify the color of light absorbed using Amas and the table on page 2 DATA TABLE A: ABSORBANCE SPECTRA Sample A for main peak (nm) Color of light absorbed Green Rurer Red 5250nm 4270 629.0 nm Yellow Blue B. BEER'S LAW 1. Sample B1 is the red dve from part A Prepare samples B2-84 according to Table 2. Mix each sample well. 2. Measure the absorbance of each standard at Ame: fill the cuvette about halfway and record the absorbance in Data Table B. Bring a clean, dry test tube or cuvette to your instructor for a sample of an unknown red dye concentration. Measure the absorbance of the unknown red solution at the appropriate Amax and record this in Data Table B. DATA TABLE B: BEER'S LAW RED DYE STANDARDS AND RED UNKNOWN 4 S1.0 Amax Unknown # standard red stock (mL) DI water (mL) total mL prepare in a Abs Conc (ppm) B1 2.00 2.00 143 M.b, , 150.0 50.0 B2 1.00 2.00 3.00 test tube . 24 B3 1.00 250 15.0 5.00 6.00 test tube B4 1.00 9.00 10.00 small beaker .068 UNKNOWN "calculate the concentrations using C,V, C2V2, where C, is 150.0ppm, V, 1.00 mL, and V2 total mL DATA ANALYSIS 1. Obtain a sheet of graph paper from your instructor and plot absorbance (y) versus concentration (x, in ppm). These data should fit a linear relationship, so draw a best-fit line with a ruler. You should follow the graphing guidelines provided with Expt. 1. The graph is worth 5 pts. Staple the graph to your report 2. Use the best-fit line on your graph to determine the concentraion of your unknown. Show your work on your giaph, and indicate your conclusior here: unknown # concentration (ppm) main color of light absorbed by the following solutions: 3. Predict the orange solution green solution: Use your graph to predict the absorbance of a 42 ppm red dye solution. Show your work on your graph, and indicate your conclusion here: 4. absorbance