Item 1: Question Solution A is analyzed for iron content using colorimetry. A calibration curve (absorbance vs ppm) is prepared and the equation of the best-fit line is A = 0.0252 C (ppm) - 0.0162. A 5.00-mL aliquout of Solution A is diluted to 100.0 mL and yields an absorbance of 0.314. Calculate the concentration of iron in solution A. 0.65 ppm 2.62 ppm O 13.1 ppm 262 ppm

Item 1: Question Solution A is analyzed for iron content using colorimetry. A calibration curve (absorbance vs ppm) is prepared and the equation of the best-fit line is A = 0.0252 C (ppm) - 0.0162. A 5.00-mL aliquout of Solution A is diluted to 100.0 mL and yields an absorbance of 0.314. Calculate the concentration of iron in solution A. 0.65 ppm 2.62 ppm O 13.1 ppm 262 ppm

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter14: Applications Of Ultraviolet-visible Molecular Absorption Spectrometry

Section: Chapter Questions

Problem 14.2QAP: A 0.4740-g pesticide sample was decomposed by wet ashing and then diluted to 200.0 mL in a...

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The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 μL�L of the sample and injecting it into a cuvette already containing 2.00 mLmL of water (total volume is 2.00 mLmL + 100.0 μL�L). The absorbance value of the diluted solution corresponded to a concentration of 6.22×10−6 M � . What was the concentration of the original solution?
From the following data calculate the potassium content per tablet in effervescent KCl bicarbonate tablets. Weight of 20 tablets = 35.6751 g Weight of tablet powder taken for assay = 0.1338 g The sample is dissolved in 500 ml of water and then 5 ml of the sample solution is taken and diluted to 100 ml. Weight of KCl used to prepare standard = 0.1912 g The standard was dissolved in 100 ml of water and 5 ml of the standard solution was diluted to 250 ml. The diluted standard solution was used to prepare a calibration series by transferring 0, 5, 10, 15, 20 and 25 ml to 100 ml volumetric flasks and making up to volume. The following readings were obtained for the calibration series: 0, 20.3, 40.1, 60.3, 80.1 and 100. Reading obtained for potassium in the diluted sample solution = 73.9. The answer in the book is 496.2 mg of K, however, I can't get to that answer. Can anyone please help with the step-by-step solution? Thanks!
Five white, 500-mg uncoated ascorbic acid (AA) tablets with an average weight of 0.6152-g were pulverized in a mortar. A sample of the powdered ascorbic acid weighing 0.4700-g was placed in an iodine flask and was dissolved in 50-mL H2SO4 then 5-g of KBr was added to the resulting solution. The solution was titrated with 47.81-mL of 0.09640 N STD. KBrO3 to reach a faint yellow endpoint then 3-g KI and 5-mL Starch TS. The blue color solution is then titrated with 2.73-mL of 0.09123 N STD. Na2S2O3 to reach the disappearance of the blue iodostarch complex. MW: KBrO3 = 167.0 ; KIO3 = 214.0 ; Na2S2O3 = 158.11 ; C6H8O6 = 176.12 Compute the milligrams of pure AA per tablet from the assay. 293.3 mg 502.5 mg None of the choices 383.9 mg
A chemist needs to create a series of standard Cu2+(aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 25.0025.00 mL of a 2.552.55 M Cu2+(aq) stock solution to a 500.0 volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu2+(aq) solution in the 100.0 mL volumetric flask.
In the determination of iron in fortified cereals by atomic absorption, 0.9133 g of sample was weighed. After a previous treatment, it was dissolved and diluted to 100 mL, an aliquot of 25.0 mL was taken, this was diluted to 100 mL and this solution presented an absorbance reading of 0.251. A series of iron standards of the following concentrations were prepared: 0.0; 1.0; 2.0; 2.5 and 3.0 ppm. Whose absorbances were 0.0; 0.241; 0.405; 0.520 and 0.640. Determine the iron concentration in mg/100 g of sample.
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An unknown food-dye is analyzed by the method used in this experiment. The absorbance of 5 standard solutions is plotted vs. their concentration (molarity) and a straight line is obtained with the formula: Abs = 3.350x +0.08 An unknown food-dye soluton is diluted and it's absorbance is found to be 0.50. What is the molarity of the diluted unknown, to two significant figures?
What weight of sample must be taken so that each 50 mg BaCl2 obtained in a gravimetric silver determination shall correspond to 10% of the Cl in the original sample? BaCl2 (208.23) Cl (35.45)
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A 10.0-mL aliquot of a standard manganese solution containing 62.5 mg/L of Mn is oxidized to MnO4- and diluted to 50.0 mL in a volumetric flask. The absorbance is measured in a 1.00-cm cell at 525 nm is 0.343. Next, a 850-mg steel sample containing manganese in dissolved in acid and diluted to 250 mL. A 50.0-mL aliquot is treated with KIO4 to oxidize Mn to MnO4- and diluted to 100.0 mL. If the absorbance at 525 nm is 0.468 in a 1.00-cm cell, calculate the weight percent of Mn in the steel.
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If a second brass washer of 0.6003 grams had been dissolved in nitric acid, diluted to 50.00 mL and then its absorbance measured at 0.450, what would be the concentration of Cu(NO3)2 in the solution? What would be the mass percent of copper in the second brass washer? Use equation of the line as y = 3.1295 x + 0.0055.