Ortho-phenanthroline reacts with ferrous ion to produce a deeply colored complex with a molar absorptivity (s) of 11,100 L/mol1 cm-1 at a max of 508 nm. You diluted the stock colored complex that you were provided using a 4 fold serial dilution. You measured the third dilution in the series in a plastic cuvette with a pathlength of 0.5 cm at 508 nm and obtained an absorbance of 0.73482. What was the concentration of the original stock solution in mM?

Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are εCo = 36400 and εNi = 5520 at 510 nm and εCo = 1240 and ε Ni = 17500 at 656 nm. A 0.361-g sample was dissolved and diluted to 150.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3-quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 1.037 at 510 nm and 0.422 at 656 nm in a 1.00-cm cell. Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample.

Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are εCo = 36400 and εNi = 5520 at 510 nm and εCo = 1240 and ε Ni = 17500 at 656 nm. A 0.361-g sample was dissolved and diluted to 150.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3-quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 1.037 at 510 nm and 0.422 at 656 nm in a 1.00-cm cell. Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample. Calculate the concentration of nickel (in ppm) in the initial solution prepared by dissolving the sample.

Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are εCo = 36400 and εNi = 5520 at 510 nm and εCo = 1240 and ε Ni = 17500 at 656 nm. A 0.361-g sample was dissolved and diluted to 150.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3-quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 1.037 at 510 nm and 0.422 at 656 nm in a 1.00-cm cell. Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample. Calculate the concentration of nickel (in ppm) in the initial solution prepared by dissolving the sample. I've asked this question multiple times and still have not gotten the right answer. This is my last question and I don't know what to do if this is also wrong.

13. A 9.50 μM standard solution of X yields an absorbance of 0.657 at 630 nm using a 1.00-cm cuvette. The molar absorptivity for X at 630 nm is a) 40,700 M-¹cm-1 b) 614,000 M-¹cm-¹ c) 1010 M-¹cm-1 d) 69,200 M¹¹cm ¹ e) 138,700 M¹¹cm¹ 14. The molar absorptivity for ferricyanide ion (FW = 211.95 g/mol) at 420 nm is 1010 M-¹cm¹. What is the concentration of ferricyanide in a solution that yields an absorbance of 0.354 in a 1.00-cm cuvette? a) 30 ppm b) 45 ppm c) 60 ppm d) 75 ppm e) 90 ppm 15. Deviations from Beer's law are observed when measurements are made a) with highly concentrated solutions b) using polychromatic light sources c) in the presence of stray light d) all of these e) none of these 16. Photometric assays typically involve measuring absorbance at an analyte's "Amax" in order to a) maximize sensitivity b) maximize selectivity c) maximize accuracy d) maximize precision e) maximize detection limit 17. The calibration curves shown at the right indicate the photometric…

Use the following information to answer the question. Molar absorptivity data for the cobalt and nickel complexes with 2,3-quinoxalinedithiol are ϵCo = 36400 and ϵNi = 5520 at 510 nm and ϵCo = 1240 and ϵ Ni = 17500 at 656 nm. A 0.457-g sample was dissolved and diluted to 200.0 mL. A 25.0-mL aliquot was treated to eliminate interferences; after addition of 2,3-quinoxalinedithiol, the volume was adjusted to 50.0 mL. This solution had an absorbance of 0.970 at 510 nm and 0.393 at 656 nm in a 1.00-cm cell. (a) Calculate the concentration of cobalt (in ppm) in the initial solution prepared by dissolving the sample. (b) Calculate the concentration of nickel (in ppm) in the initial solution prepared by dissolving the sample.

Unknown Analysis: Calculate the mass spec. of 88g per mole. (show calculations and formulas) Below is a picture of the IR scan.

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Solutions of cobalt (II) ions have a magenta color with a molar absorptivity constant (e) value at 511 nm of 5.87 M-1cm-1.   A 0.500 mL sample is transferred from a 50.0 mL stock solution of Co(NO3)2 and diluted with water to a final volume of 7.50 mL.  The dilution had an absorbance value at 511 nm in a standard cuvette (1.00 cm light path) of 0.382. Calculate the mass of Co(NO3)2 contained in the original 50.0 mL stock solution.

Chris wants to study an organometal complex that was synthesized as shown below. Cr3+ + 2salen) = Cr(salen),³ He first prepared the working standards by adding specific volumes of Cr3+ solution and added 5.00 ml of 0.500M salen and diluted the solutions to 32.0 ml. The absorbance of each standard was then measured at the Amax, 425 nm, using a UV-Vis spectrophotometer as shown in the table below. Table 1. Standardized solutions containing Cr(salen);". Concentration (M) Blank Absorbance 0.021 0.010 0.015 0.220 0.295 0.020 0.025 0.356 0.421 0.473 0.030 He then prepared an unknown solution by mixing 1.00-ml of 0.500 M Cr3+ with 2.00-ml of 0.500 M salen and diluting to 32.0 mL. The resulting mixture was found to have an absorbance of 0.285. A blank solution was run before analyzing the unknown and gave an absorbance of 0.015. A. Determine the best fit line (with r) of the calibration curve. B. Calculate the equilibrium concentration (mM) of Cr3+ in the sample. c. Calculate the equilibrium…