Concept explainers
Interpretation:
The solution containing
Concept introduction:
The absorbance of the solution is the ability of the solution to absorb the monochromatic light passing through it. The absorbance of the solution is defined as the ratio of the intensity of light incident on the solution to the intensity of light absorbed by the solution.
The relation between the initial and final concentration of the solution after dilution can be given by.
The relation between the absorbance, path length, molar absorptivity and the concentration of the complex solution is:
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Chapter 13 Solutions
PRINCIPLES OF INSTRUMENTAL ANALYSIS
- Mixing the chelating reagent B with Ni(II) forms the highly colored NiB22+, whose solutions obey Beer’s lawat 395 nm overa wide range. Provided the analytical concentration of the chelating reagent exceeds that of Ni(II) by a factor of 5 (or more), the cation exists, within the limits of observation, entirely in the form of the complex. Use the accompanying data to evaluate the formation constant Kf for the process Ni2++2BNiB22+arrow_forwardAt 580 nm, which is the wavelength of its maximum absorption, the complex Fe(SCN)2+ has a molar absorptivity of 7.00 I03L cm-1 mol-1.Calculate (a) the absorbance of a 4.47 10-5 M solution of the complex at 580 nm in a 1.00-cm cell. (b) the absorbance of a solution in a 2.50-cm cell in which the concentration of the complex is one half that in(a). (c) the percent transmittance of the solutions described in (a) and (b). (d) the absorbance of a solution that has half the transmittance of that described in (a).arrow_forwardA FeSCN complex, whose maximum absorbance is at a λ of 580 nm, has a molar extinction coefficient of 5×103 M-1cm-1 . A solution is measured with a 25 mm cell at the same λ , obtaining 20.6% T. Calculate the concentration in [ppm] of the complex in the solution.arrow_forward
- A 2.50 mL aliquot of a solution that contains 3.85 ppm Fe(III) is treated with an appropriate excess of KSCN and diluted to 100.0 mL. What is the absorbance of the resulting solution at 580 nm in a 0.50 cm cell? (Molar absorptivity of Fe (SCN)2+is 7.0 x 105L mol-1cm-1).arrow_forward*13-7_ A solution containing the complex formed between Bi(III) and thiourea has a molar absorptivity of 9.32 X 10³ L mol¹ cm¹ at 470 nm. 00.5 701 X 00.A 1910 919 juloa wot What is the absorbance of a 4.25 × 10-5 M : I solution of the complex at 470 nm in a 1.00-cm cell? (a) W (b) (alios mo-00.1) What is the percent transmittance of the solution described in (a)? (c) 200 What is the molar concentration of the complex in a solution that has the absorbance described in Torito or tovo (a) when measured at 470 nm in a 2.50-cm cell? (non?+ 1rdarrow_forwardThe standard curve was made by spectrophotographic analysis of equilibrated iron(III) thiocyanate solutions of known concentration. You are asked to analyze a Fe(SCN)2+Fe(SCN)2+ solution with an unknown concentration and an absorbance value of 0.4150.415 . The slope-intercept form of the equation of the line is ?=4558.4?+0.0147y=4558.4x+0.0147 . The unknown was analyzed on the same instrument as the standard curve solutions at the same temperature. What is the Fe3+Fe3+ concentration of the unknown solution?arrow_forward
- A 2.50 mL aliquot of a solution that contains 3.85 ppm Fe(III) is treated with an appropriate excess of KSCN and diluted to 100.0 mL. What is the absorbance of the resulting solution at 580 nm in a 0.50 cm cell? (Molar absorptivity of Fe (SCN)2+is 7.0 x 105L mol-1cm-1). AW: K =39.098 S=32.08 C=12.011 N=14.007 Fe=55.845arrow_forwardA 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...arrow_forwardYou wish to measure the iron content of the well water on the new property you are about to buy. You prepare a reference standard Fe3+ solution with a concentration of 5.53×10−4 M. You treat 10.0 mL of this reference with HNO3 and excess KSCN to form a red complex and dilute the reference to 45.0 mL. The diluted reference is placed in a cell with a 1.00‑cm light path. You then take 20.0 mL of the well water, treat with HNO3 and excess KSCN, and dilute to 100.0 mL. This diluted sample is placed in a variable pathlength cell. The absorbance of the reference and the sample solutions match when the pathlength is 3.25cm. What is the concentration of iron in the well water? For each solution, the zero is set with a blank.arrow_forward
- 4. Calculate the expected absorbance of solution of a 5.50x10-6 M solution of Blue # measured at 629 nm in a 1.50cm cell. The molar absorptivity for Blue #1 is 1.30x105 M-1.cm-1 at 629 nm.arrow_forwardA solution in part C initially contains (4.0300x10^-4) molar SCN¯ and (2.880x10^-3) molar Fe3+. This solution was then measured using the colorimeter, and an absorbance of (4.8600x10^-1) was recorded.The constant determined in part A of the experiment was found to be (3.40x10^3). Using the data provided above, determine the equilibrium constant for the reaction. Note: Your answer is assumed to be reduced to the highest power possible. Your Answer: х10 Answerarrow_forwardYou are working with metal thiocyanate complex, M(SCN)+, with a molar absorptivity constant, ε, of 2700 cm−1M−1 at 500 nm. If you are is using a 1.00 cm cuvette for absorbance measurements at 500 nm, what concentration of M(SCN)+ will give an absorbance value of 0.280?arrow_forward
- Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage LearningPrinciples of Modern ChemistryChemistryISBN:9781305079113Author:David W. Oxtoby, H. Pat Gillis, Laurie J. ButlerPublisher:Cengage Learning