A simultaneous determination for cobalt (Co) and nickel (Ni) can be based upon absorption by their respective 8-hydroxyquinolinol complexes. Molar absorptivities corresponding to their absorption maxima are as follows: Molar Absorptivity, 8 365 nm 700 nm Co 3600 430 Ni 3200 10 The absorbances of a sample at 365 nm and 700 nm with a 1.00-cm cell are 0.600 and 0.040, respectively. Calculate the molar concentration of nickel (cN:) and cobalt (cco) in the sample. A. CN = 3.20 x 10$ M, ccs = 3.60 x 10$ M B. CNi = 3.60 x 10$ M, cco =3.20 x 10$ M C. CNi = 1.00 x 10° M, ccs = 4.13 × 105 M D. CN = 8.70 x 10$ M, cco = 9.10 x 10$ M E. CNi = 9.10 x 105 M, cco = 8.70 x 105 M

Iron(III) forms a complex with thiocyanate ion that has the formula Fe(SCN)+2. The complex has an absorption maximum at 580nm. A sample of well water was assayed according to the following scheme: Sample Sample Vol (mL) Oxidizer Fe(ii) (mL) added 2.75ppm KSCN (0.050 M) H20 (mL) Abs @ 580 nm 1 50.00 5.00 5.00 20.00 20.00 .549 2 50.00 5.00 0 20.00 25.00 .231 What is the concentration of Fe in the well water sample?

A 0.0138 gram sample of brass was dissolved in a approximately 1 ml of nitric acid and then diluted to 250.0 ml using a volumetric flask. The 20% dilution of the unknown gave an average absorbance of 0.3514 at 213.9 nm. A zinc calibration curve is shown below. Calculate the percentage of zinc in the brass sample. Show your work in the space below. Zn Calibration Curve 1.2 y-0.8339x + 0.0452 R 0.99788 08 06 04 04 Concentration (ppm) Absorbance @ 213.9 nm

A student prepared an equilibrium system using Fe(NO3)3 and KSCN, which reacted to produce iron(III) thiocyanate by the balanced reaction shown below. Fe3+ + SCN' + FESCN2+ Previously the student prepared a Beer's Law calibration plot of absorbance (y-axis) versus FESCN2+ (x-axis) and calculated a trendline with the equation of y = 3229x. The student then prepared another equilibrium mixture using the following amounts. 0.00200 M Fe(NOa)a (mL) 0.00200 M KSCN (mL) 0.1 M HNO3 (mL) Absorbance 6.00 3.00 16.00 0.258 Use the above data to find initial and equilibrium concentrations of each species and use an ICE table to calculate Keg. [ Fe+ ] initial: [ SCN' ] initial: [ FESCN2+ ] initial: [Fe3+ ] at equilibrium: [ SCN' ] at equilibrium: [ FESCN2+ ] at equilibrium: Keg =