(a)
Interpretation:
The absorbance of the solution containing the complex formed between
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 absorbance, path length, molar absorptivity and the concentration of the solution is given as.
(b)
Interpretation:
The percent transmittance of the solution formed from the complex between
Concept introduction:
The percent transmittance of a solution is the ability of the solution to allow the monochromatic light to pass through it. The percent transmittance of a solution is the ratio of the intensity of monochromatic light incident on the solution to the intensity transmitted through the solution.
The relation between the absorbance and transmittance is established by the Beer’s law.
(c)
Interpretation:
The concentration of the solution is to be determined for the change in the path length of the cell containing the solution.
Concept introduction:
The concentration of the solution, path length of the cell and the molar absorptivity of the solution plays an important role in determining the absorbance of the solution. If any of the parameter is affected, it leads to change in the absorbance of the solution.
The relation between the absorbance, path length, molar absorptivity and the concentration of the solution is given as.
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Chapter 13 Solutions
Principles of Instrumental Analysis, 6th Edition
- A standard solution was put through appropriate dilu tions to give the concentrations of iron shown in the ac companying table. The iron(II)-1,10,phenanthroline complex was then formed in 25.0-ml aliquots of these solutions, following which each was diluted to 50.0 mL (see color plate 15). The absorbances in the table (1.00-cm cells) were recorded at 510 nm Fe(II) Concentration in Original Solution, ppm Aşie 4.00 0.160 0.390 10.0 16.0 0.630 24.0 0.950 32.0 1.260 40.0 1.580 (a) Plot a calibration curve from these data. (b) Use the method of least squares to find an equa tion relatin g absorbance and the concentration of iron(II). (c) Calculate the standard deviation of the slope and intercept.arrow_forwardA solution containing the complex formed between Bi(III) and thiourea has a molar absorptivity of 9.32 x 103 M-1 cm-1 at 470 nm. (a) Calculate the absorption of a 4.25x10-5 M solution of the complex at 470 nm in a 1-cm cell. (b) What is the molar concentration of the complex in a solution that has the calculated absorption in (a) when measured at 470 nm in a 2.50 cm cell?arrow_forwardA standard solution was put through appropriate dilutions to give the concentrations of iron shown in the table that follows. The iron(II)-1,10-phenanthroline complex was then formed in 25.0-mL aliquots of these solutions, following which each was diluted to 50.0 mL. The following absorbances (1.00-cm cells) were recorded at 510 nm: Calculate the concentration, in ppm, of a sample with an abosrbance of 0.829. Fe(II) concentration (ppm) A510 4.00 0.160 10.0 0.390 16.0 0.630 24.0 0.950 32.0 1.260 40.0 1.580arrow_forward
- A 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_forwardAt 590 nm, crystal violet (a biological stain) has a molar absorptivity (ε) of 8.7×104 M-1cm-1. Using Beer's Law, calculate the concentration of crystal violet in a solution with a measured absorbance (A) of 1.254. The path length (b) is 1.00 cm.arrow_forward7. A solution containing the complex formed between Bi(III) and thiourea has a molar absorptivity of 9.32 x 10° L·cm-1-mol-1 at 470 nm. (a) What is the absorbance of a 6.24 x 10-5 M solution of the complex in a 1.00-cm cell? (b) What is the percent transmittance of the solution described in Part (a)? (c) What is the molarity of the complex in a solution that has the same absorbance as the solution in Part (a), but was measured in a 5.00-cm cell?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_forwardThe transmittance of a solution measured at 590 nm in a 1.5-cm cuvette was 76.2%. (a) What is the corresponding absorbance?(b) If the concentration is 0.0802 M, what is the absorptivity of this species at this wavelength? (c) If the absorptivity is 10,000 L mol-1 cm-1, what is the concentration?arrow_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
- A 2.78 ✕ 10−4 M solution of a compound has an absorbance of 0.417 at 520 nm in a 1.00 cm cell. The solvent's absorbance under the same conditions is 0.020. (a) What is the molar absorptivity of the unknown compound? M -1cm-1(b) What is the concentration of the compound in a solution, if the absorbance of the solution in a 1.00 cm cell at 520 nm is 0.391? Marrow_forwardThe absorption coefficient of a glycogen-iodine complex is 0.20 at light of 450 nm. What is the concentration when the transmission is 40 % in a cuvette of 2 cm?arrow_forward3.) The accuracy of a spectrophotometer is evaluated by preparing a solution of 60.06 ppm K2Cr2O7 and measuring its absorbance at a wavelength of 350 nm in a cell with a pathlength of 1.00 cm. The expected absorbance is 0.640. What is the expected molar absorptivity of K2Cr2O7 at this wavelength?arrow_forward
- Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning