(a)
Interpretation:
The ligand-to-metal ratio in the product should be determined.
Concept introduction:
In the method of continuous variation, cation and ligand solutions which have same concentration are mixed in such a way that total number of moles of reactants and the total volume of each mixture are constant. But the mole ratio varies. Then the absorbance of the mixture is measured and absorbance is corrected. The corrected absorbance is plotted against volume fraction of one reactant. A maximum or a minimum occur at metal to ligand volume ratio equals to the combined ratio of metal to ligand.
(b)
Interpretation:
Average molar absorptivity of the complex and its uncertainty should be calculated.
Concept introduction:
In the method of continuous variation, cation and ligand solutions which have same concentration are mixed in such a way that total number of moles of reactants and the total volume of each mixture are constant. But the mole ratio varies. Then the absorbance of the mixture is measured and absorbance is corrected. The corrected absorbance is plotted against volume fraction of one reactant. A maximum or a minimum occur at metal to ligand volume ratio equals to the combined ratio of metal to ligand.
(c)
Interpretation:
Kf for the complex should be determined
Concept introduction:
In the method of continuous variation, cation and ligand solutions which have same concentration are mixed in such a way that total number of moles of reactants and the total volume of each mixture are constant. But the mole ratio varies. Then the absorbance of the mixture is measured and absorbance is corrected. The corrected absorbance is plotted against volume fraction of one reactant. A maximum or a minimum occur at metal to ligand volume ratio equals to the combined ratio of metal to ligand.
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Chapter 14 Solutions
Principles of Instrumental Analysis
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- 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?arrow_forwardLooking at a d6 Tanabe-Sugano diagram needed to assign the electronic transistion that corresponds to (lambda)max off 550 nm. Give that the Racah parameter for the iron complex in this complex is 848 cm^-1, determine the lighand field parameter in cm^-1 for the complex in the spin-state associated with lambda max. complex: [Fe(NH2trz)3]Cl2·2H2Oarrow_forwardThe absorbance values observed during the determination of the complex stoichiometry with the Job method using the spectroscopic method were plotted and the following correct equations were obtained. What is the n value of the compound formed by Fe + 3 and SCN- ions? 1. Line equation: y = 2.6188x + 0.16082. Line equation: y = -2.5963x + 2.7203arrow_forward
- Vanadium forms a complex with peroxide which absorbs at 460 nm. A 3.96 x 10-4M solution of vanadium peroxide (Solution A) exhibited an absorbance of 0.624 at 460 nm in a 1.000-cm quartz cuvette; a blank solution containing only solvent had an absorbance of 0.029 at the same wavelength. a) Find the molar absorptivity of vanadium peroxide complex. b) An unknown solution of vanadium peroxide complex in the same solvent and cuvette had an absorbance of 0.375 at 460 nm. Find the concentration of vanadium peroxide in the unknown solution. c) A concentrated solution vanadium peroxide in the same solvent was diluted from an initial volume of 5.00 mL to a final volume of 25.00 mL (Solution C) had an absorbance of 0.733 in the same cuvette. What is the concentration of vanadium peroxide in the concentrated solution (Solution B)? Answer the following questions: 1. Molar Absorptivity (M1 cm) of vanadium peroxide complex from Solution A at 460 nm 2. Concentration of vanadium peroxide in unknown…arrow_forwardThe molar absorptivity (ε) of the FeSCN2+ complex ion is 4700 M-1 · cm-1 at a wavelength of 450 nm. Using a 1-cm sample tube, you measure the absorbance as (2.0x10-1). What is the concentration of FeSCN2+?arrow_forwardThe Racah parameter B for [Co(CN)6]3−=460cm−1, and [Co(NH3)6]3+= 615cm−1. Explain the difference in nephelauxetic effect. Thank you!arrow_forward
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