Absorbance at 453 nm 8393939 7 fl. oz./20 ml Beer-Lambert's Law (Spectrophotometry) #1 Fe (aq) + KSCN(s) FESCN "(aq) + K" (aq) 3+ To determine the moles of Fe (aq) in a 100. mL sample of an unknown solution, excess KSCN(s) is added to convert all the Fe (aq) into the dark red species FeSCN"(aq), as represented by the equation above. The absorbance of FESCN"(aq) at different concentrations is shown in the graph below. 2+ 0.50 目0.40 0.30 0.20 01 0. 0. 5 x 10-5 10 x 10-5 Concentration of FESCN2+ (M) If the absorbance of the mixture is 0.20 at 453 nm, haw many moles of Fe (aq) were present in the 100. mL sample? (Assume that any volume change due to adding the KSCN(s) Iis negligible.) 3+, 4x10-4 mol 3 x 104 mol (B) 4x 10-6 mol 3x 10-6 mol

(5) A sample of sodium phosphate is dissolved in water to give 100.00 mL of solution (Solution A). Then this solution is diluted 5 times to give the final solution (Solution B). Solution B is Known to contain 3.920 x 1022 number of PO43- ions, which has an absorption peak at 460 nm and absorbance value of 0.355 in a 1.000 cm cuvette. (i) Calculate the molar absorptivity of Solution B. (ii) What mass of sodium phosphate (MM 163.94 g/mol) dissolved in Solution A.

What would be a reasonable guess for the wavelength of maximum absorbance for FD&C Orange 2?

For the aqueous [HgI4]complex Ky = 6.76 × 1029 at 25 °C. Suppose equal volumes of 0.0062 M Hg (NO3)2 solution and 0.42M Nal solution are mixed. Calculate the equilibrium molarity of aqueous Hg** ion. Round your answer to 2 significant digits. ☐ M

Calculate the path length in centimetres which would give an absorbance of 0.134 of a colored dye with a molar absorptivity of 0.759 L mol-1 cm-1 at a wavelength of 645 nm if the concentration of the dye is 6.82x10-2 M. Report your answer to 3 significant figures.

What is the absorbance of a theoretical compound in a 5.26x10-5 M solution, a path length of 1.5cm, and a molar absorptivity of 37.4 mol / L cm?

A series of standard iron-phenanthroline [Fe(phen)3]2+ complex ion solutions were prepared. The absorbance of each solution was measured at a wavelength of 510 mm. A calibration curve of absorbance vs. concentration was then plotted to obtain a linear equation of y = 0.0018x+0.0749. The absorbance of an unknown [Felphenly solution was measured to be 0.326. Calculate the concentration of the complex ion. NOTE! Report your answer as a WHOLE #. Type your answer...

You want to determine the amount of iron(III) in acomplex salt. You make a 100.0 mL solution of the complex salt by dissolving 0.0670 g of complex salt with water to the mark on a 100.0 mL volumetric flask. You get an absorbance reading for the iron from the spectrometer of 0.334. The molar absorptivity is determined to be 17605 L/mole∙cm and the pathlength is 1.00 cm. Determine the molarity of iron(III) in solution. Determine the mass percentage of iron(III) in the complex salt.

The absorbance of 10 mL of 0.0005 M Co2+ solution is 0.35. 10 mL of this solution mixed with 10 mL of the sample solution produces an absorption of 0.52. Calculate the concentration of Co2+ in the sample

Absorbance measurements were taken on a series of Fe standards complexed with 1,10-phenanthroline. A plot of absorbance vs. concentration yielded a linear curve with the equation y=1.008e03x + 0.0395 (where y is the absorbance and x represents the Fe concentration in moles/L). Using this information calculate the Fe concentration (in ppm) in a 40.0-mL aliquot of ground water that produced an absorbance of 0.580.