3) Consider the following spectroscopic data for the indicators thymol blue, semithymol blue, and methylthymol blue. A solution of these three species in a 1.00-cm cuvette had absorbances of 0.412 at 455 nm, 0.350 at 485 nm, and 0.632 at 545 nm. Use linear algebra in Excel to calculate the molarities of the three species. λ/nm 455 485 545 Thymol blue 4800 7350 36400 ε/ M¹¹ cm¹¹ Semithymol blue 11100 11200 13900 Methylthymol blue 18900 11800 4450

You have a 2.5 M aqueous sample of a metal ion, which has an absorbance of 0.75 at 660 nm. An unknown solution of the same metal ion, on the same day Review Beer's Law. and on the same spectrophotometer, has a measured absorbance of 0.59. What is the concentration of metal ion in the unknown solution? In vour notohookı

2. ] You make 150.0 mL of a copper(II) sulfate solution but forget to cover it before leaving for the day. The next class, you measure the volume and find that you only have 132.0 mL remaining. You didn’t record the initial concentration, but you measure the absorbance of the remaining solution at 620 nm and find that it is 0.386. You also construct the following calibration curve for CuSO4: Standard solution Abs620 0.50 M 0.424 0.40 M 0.336 0.30 M 0.247 0.20 M 0.159 (refer to image) a. What is the value for k (in Beer’s Law)? Provide a calculation or graph to support your answer. b. What is the concentration of the (remaining) solution? c. What was the concentration of the original solution from the first class? d. If you removed 7.5 mL from the 132.0 mL solution in the process of measuring the absorbance, how much water should you add to obtain the original concentration that you solved for in part (c)?

Find the concentration of benzene in hexane if the absorbance is 0.188 in a 1.000-cm cell.

At 350 nm, the absorbance of a solution of 60.06-ppm K2Cr207 in 0.0050 M H2SO, in 0.640 (b=1). What is the molar absorbitivity of K2Cr207 at this wavelength?

Blue Blue dye stock solution Absorbance at 630 nm Calibration curve Part 1: 0.1944 M 0.00697 y = 0.0682x A purple solution is prepared by mixing 5.00 mL of the blue dye solution with 6.75 mL of red dye solution. The calibration curve for each color is provided. Part 2 out of 3 (a) Determine the theoretical molar concentration of each dye in the mixture. [Blueltheoretical = 8.27 x 10-2 [Red] theoretical = 1.16 [Bluelexperimental [Redlexperimental " *10-1 M M x 10 (b) Using the absorbance and calibration curve for each dye, calculate the experimental molar concentration of each dye in the mixture. x 10 Red Red dye stock solution Absorbance at 500 nm Calibration curve 0.2015 M 0.00193 y = 0.0170x M M

.Q1. To determine the concentrations (mol/L) of Co(NO3)2 (A) and Cr(NO3)3(B) in an unknown sample, the following representative absorbance data wereobtained.A (mol/L) B (mol/L) 510nm 575nm5×10−1 0 0.714 0.0970 6×10−2  0.298 0.757Unknown Unknown 0.671 0.330Measurements were made in 1.0 cm glass cells.i. Calculate the four molar absorptivities: ∈A(510), ∈A(575), ∈B(510) and ∈B(575).ii. Calculate the molarities of the two salts A and B in the unknown.

A standard curve of absorbance vs. concentration has a linear trendline of y = 0.56x + 0.987. Use this trendline to calculate the concentration of an unknown sample that has an absorbance of 1.245.

Following is a table of data showing the absorbance of a solution of cobalt(II)  ion at different concentrations at a wavelength of 510 nm.  .      Absorbance          Concentration (M)         0.450                    0.044          0.691                      0.072          0.894                      0.096          1.210                      0.125          You are given a solution of  unknown concentration containing cobalt(II) ions, which gives you an  absorbance of 0.67.          Calculate the unknown conc., using data from  the table given  above.           (A = kC). Use the average ‘k’ value from the above set of data.

4. An ethanol solution of p-aminosalicylic acid has a molar absorptivity of 1.6 x 10ʻL mol"cm at a wavelength of 284 nm. Calculate the absorbance of a 4.8 x 10°M solution in a 1.000 cm cuvette at this wavelength.