Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Question
Chapter 13, Problem 13.24QAP
Interpretation Introduction
Interpretation:
As several absorbance values have been given under 375 nm, the most accurate way is to construct a graph between absorbance & the concentration of CrO42- solution. After using the value of slope & considering the chemical equation of Beer-Lambert law, absorptivity and the molar absorptivity of CrO42- should be calculated.
Concept introduction:
The absorbance of light can be determined by the Beer-Lambert law. The chemical equation relevant to the law is,
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
The absorbance of a 1.05x10-5 M Fe+3 determined at 580 nm using a 2.50-cm cell was said to be 0.200. What is the molar absorptivity of this solution in liters/mole cm?
The 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+ solution with an unknown concentration and an absorbance value of
0.392. The slope-intercept form of the equation of the line is y = 4538.1x +0.0077. The unknown was analyzed on the same
instrument as the standard curve solutions at the same temperature.
What is the Fe³+ concentration of the unknown solution?
[Fe³+] =
mol/L
Absorbance
Iron(III) thiocynate standard curve
1.0
V
0.5
0.0001
Fe³+ concentration (M)
0
0.0002
Suppose that a solution has an absorbance of 0.250 at a wavelength of 450 nm. If the concentration of the solution is 22 μM, what is the value of the molar absorptivity? The data were taken with a standard 1-cm cuvette.
molar absorptivity in (L cm^−1 mol^-1):
Chapter 13 Solutions
Principles of Instrumental Analysis
Ch. 13 - Prob. 13.1QAPCh. 13 - Prob. 13.2QAPCh. 13 - Prob. 13.3QAPCh. 13 - Prob. 13.4QAPCh. 13 - Prob. 13.5QAPCh. 13 - Prob. 13.6QAPCh. 13 - Prob. 13.7QAPCh. 13 - At 580 nm, which is the wavelength of its maximum...Ch. 13 - Prob. 13.9QAPCh. 13 - Zinc(II) and the ligand L form a 1:1 complex that...
Ch. 13 - The equilibrium constant for the conjugate...Ch. 13 - The equilibrium constant for the reaction...Ch. 13 - Prob. 13.13QAPCh. 13 - Prob. 13.14QAPCh. 13 - Prob. 13.15QAPCh. 13 - Prob. 13.16QAPCh. 13 - Prob. 13.17QAPCh. 13 - Prob. 13.18QAPCh. 13 - Prob. 13.19QAPCh. 13 - Prob. 13.20QAPCh. 13 - Prob. 13.21QAPCh. 13 - Prob. 13.22QAPCh. 13 - Prob. 13.23QAPCh. 13 - Prob. 13.24QAPCh. 13 - Prob. 13.25QAPCh. 13 - Prob. 13.26QAPCh. 13 - Prob. 13.27QAP
Knowledge Booster
Similar questions
- The molar absorptivity of a compound at 500 nm wavelength is 252 M-1cm-1. Suppose one prepares a solution by dissolving 0.00140 moles of a solute in enough water to make a 500.0 mL solution. What would be the absorbance in a 4 .00 mm pathlength cell?arrow_forwardCalculate the molar absorptivity of a solute when its measured absorbance is 1.050 with a concentration of 1.45 x 10-3 M. Assume the path length of the cell is 1.0 cm.arrow_forwardIf the apparent molar absorptivity of cefuroxime sodium is 2.046 × 103 L mol−1 cm−1 in a 1-cm cuvette, at what concentration should the standard and sample solutions be prepared to result to an ideal absorbance value of 0.500? Show your solution.arrow_forward
- Fe+3 (aq) + SCN – (aq) FeSCN +2 (aq) She mixes 4.00 mL of 2.00 mM SCN– and 5.00 mL of 2.00 mM Fe+3 ions, then diluting with 1.00mL of water to give a total volume of 10.00mL. She measures the absorbance of the solution asbeing 0.210. If she has previously calculated the molar absorbtivity constant (ε) of the product tobe 2583 cm–1 M–1, what is her best estimate for the K value for this reaction?arrow_forwardWhat is the absorbance of a 2.33×10−4M2.33×10−4M solution of a compound with a molar absorptivity of 1.05×103M−1cm−11.05×103M−1cm−1 in a 1.00 cm cell?arrow_forwardTreatment of ammonia with phenol in the presence of hypochlorite yields indophenol, a blue product that absrobs light at 625 nm, which çan be used for the spectrophotometric determination of ammonia. gan OCF OH + NH3 indophenol anion To determinè the ammonia concentration in a sample of lake water, three samples are prepared. In sample A, 10.0 mL of lake water is mixed with 5 mL of phenol solution and 2 mL of sodium hypochlorite solution, and diluted to 25.0 mL in a volumetric flask. In sample B, 10.0 mL of lake water is mixed with 5 mL of phenol solution, 2 mL of sodium hypochlorite solution, and 2.50 mL of a 5.50 x 10-4 M ammonia solution, and diluted to 25.0 mL. Sample C is a reagent blank. It contains 10.0 mL of distilled water, 5 mL of phenol solution, and 2 mL of sodium hypochlorite solution, diluted to 25.0 mL. The absorbance of the three samples is then measured at 625 nm in a 1.00 cm cuvette. The results are shown in the table. Sample Absorbance (625 nm) A 0.361 B 0.608 C…arrow_forward
- The 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_forwardThe absorbance value for the Standard was 0.625 and [FeSCN^ 2+ ] std is 2.00E 4M Calculate the [FeSCN^ 2+ ] in the equilibrium mixture, report the answer to the correct significant figures. The absorbance of the equilibrium solution was 0.451arrow_forwardA 5.00×10−4 M solution of analyte is placed in a sample cell that has a pathlength of 1.00 cm. At a wavelength of 490 nm, the solution’s absorbance is 0.338. What is the analyte’s molar absorptivity at this wavelength?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_forwardA student measures k for a certain blue dye to be 400.4 M-1 at 560 nm. What is the molarity of the dye in a solution with an absorbance of 0.118 at this wavelength?arrow_forwardThe un-ionized form of the weak acid HA does not absorb in the visible region. When it ionizes, its conjugate base (A-) absorbs light strongly at 510 nm. The following data were obtained by measuring the absorbance at 510 nm of solutions with a concen- tration of 1.0 x 104 M HA in different pH buffers. pH Absorbance 2.0 0.00 3.0 0.00 4.0 0.00 5.0 0.025 6.0 0.180 7.0 0.480 8.0 0.570 9.0 0.595 10.0 0.595 11.0 0.595 12.0 0.595 What is the approximate pK of HA?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning