625 nm, which can be used for the spectrophotometric determination of ammonia. ocr -OH • NH, indophenol anion To determine 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 × 104 M ammonia solution, and diluted to 25.0 mlL. 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 0.374 B 0.621 0.045 What is the molar absorptivity (e) of the indophenol product? M'cm What is the concentration of ammonia in the lake water? [NH,Jhtc water M

625 nm, which can be used for the spectrophotometric determination of ammonia. ocr -OH • NH, indophenol anion To determine 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 × 104 M ammonia solution, and diluted to 25.0 mlL. 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 0.374 B 0.621 0.045 What is the molar absorptivity (e) of the indophenol product? M'cm What is the concentration of ammonia in the lake water? [NH,Jhtc water M

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

Chapter9: Atomic Absorption And Atomic Fluorescence Spectrometry

Section: Chapter Questions

Problem 9.1QAP

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what is the purpose and what is it for Spectrophotometric of a Cobalt Chloride Solution Analysis?
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Nitrite ion, NO2-, is a preservative for bacon and other foods, but it is potentially carcinogenic. A spectrophotometric determination of NO2- makes use of the following reactions: A 5.00 cm cell was used to measure absorbance. Here is an abbreviated procedure for the determination. 1. To 50.0 mL of unknown solution containing nitrite is added 1.00 mL of sulfanilic acid solution. 2. After 10 min, 2.00 mL of 1-aminonapthalene solution and 1.00 mL of buffer are added. 3. After 15 min, the absorbance is read at 520 nm in a 5.00-cm cell. The following solutions were annaylzed: A. 50.0 mL of food extract known to contain no nitrite(that is a neglible amount); final absorbance =0.153 B. 50.0 mL of food extract suspected of containg nitrite ; final absorbance= 0.622 C. Same as B, but with 10 microliters of 7.50x10^-3 M NaNO2 added to the 50.0 mL sample; final absorbance= 0.967 a) Calculate the molar absorptivity of the colored product. Remember that a 5.00 cm cell was used b) How many…
A mixture containing only KCl and NaBr is analyzed by the Mohr method. A 0.2125-g sample is dissolved in 25 mL of water and titrated to the Ag2CrO4 endpoint, requiring 25.63 mL of 0.1110 M AgNO3. A blank titration requires 1.15 mL of titrant to reach the same end point. Report the %w/w KCl and NaBr in the sample. KCl = 74.551 NaBr = 102.89