A student performed an experiment on the determination of dissolved oxygen in a water sample using the Winkler Titration Method. What is the amount of (A) dissolved oxygen and (B) oxygen in the water sample? Use the data and results recorded by the student in the table below. Volume of Sodium Thiosulfate 20.84 mL used in Titration Volume of Water Sample 100 mL Established Relationship 10 ml of 0.0125 M Na,S,O3 = 1 mg/L O2 Concentration of Standardized Sodium Thiosulfate Amount of Dissolved Oxygen in (A) the Water Sample Amount of Oxygen in the Water (B) Sample 0.0245 N

A student performed an experiment on the determination of dissolved oxygen in a water sample using the Winkler Titration Method. What is the amount of (A) dissolved oxygen and (B) oxygen in the water sample? Use the data and results recorded by the student in the table below. Volume of Sodium Thiosulfate 20.84 mL used in Titration Volume of Water Sample 100 mL Established Relationship 10 ml of 0.0125 M Na,S,O3 = 1 mg/L O2 Concentration of Standardized Sodium Thiosulfate Amount of Dissolved Oxygen in (A) the Water Sample Amount of Oxygen in the Water (B) Sample 0.0245 N

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter31: Introduction To Analytical Separations

Section: Chapter Questions

Problem 31.21QAP

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A sample is analyzed for chloride by the Volhard method. From the following data, calculate the percentage of chloride present:Weight of sample = 6.0000 g dissolved and diluted to 200 mLAliquot used = 25.00 mL AgNO3 added = 40.00ml of 0.1234MKSCN for back titration = 13.20ml of 0.0930M
The SO2 present in air is mainly responsible for the phenomenon of acid rain. The concentration of SO2 can be determined by titrating against a standard permanganate solution as follows: 5SO2 + 2MnO4- + 2H2O ---> 5SO42- + 2Ms2 + 4H+ Calculate the number of grams of SO2 in a sample of air if 4.90mL of 0.00700M KMnO4 solution are required for the titration. Be sure your answer has the correct number of significant digits.
It is required to know the concentration of an aqueous solution of H2SO4 that appeared in the laboratoryChemistry III and it's unlabeled. To this end, a student of analytical chemistry carried out the followingProcedure: He took 5.00 mL of a fresh and standardized solution of 0.525M NaOH and brought them to a250.0 mL balloon to be completed with distilled water. Subsequently, he poured 15.00 mL of the solutionH2SO4 of unknown concentration in an Erlenmeyer flask and added 2 drops of phenolphthalein.Using a burette filled with the last NaOH solution, he noticed that when adding 39.40 mL of the hydroxidethe Erlenmeyer solution reached a faint but permanent pink. With the above dataDetermine the concentration and pH of the H2SO4 solution.
To determine the concentration of glucose in the packaged juice industry, 50 mL of sample is analyzed. Analysis of it (and other reducing sugars) was carried out there using triiodide back titration. An excess volume of 75.00 mL of 0.338 M triiodide standard solution in alkaline medium was added to the glucose solution. The resulting solution was acidified and the excess triiodide was titrated with 18.37 mL of standard 0.526 M thiosulfate solution. Calculate is the concentration in ppm in the sample. In alkaline medium: Glucose (C6H12O6) / Gluconate (C6H11O7-), Triiodide (I3- ) / Iodide (I-) In acid medium: Thiosulfate (S2O32-) / Tetrathionate (S4O62-), Triiodide (I3- ) / Iodide (I-)
00 mL of a diprotic acid primary standard solution was accurately prepared to a concentration of 0.1431 M. Three samples of this primary standard solution were used as samples in a titration to standardize an aqueous solution of sodium hydroxide, NaOH, which would be used as a titrant. Using the following table of data for the titration of the primary standard acid with NaOH, calculate the average concentration of NaOH. Trial # Volume of primary standard Initial titrant volume Final titrant volume 1 10.00 mL 8.21 mL 27.22 mL 2 10.00 mL 27.22 mL 46.23 mL 3 10.00 mL 30.28 mL 49.29 mL 0.1506 M 0.0753 M 0.0376 M 0.1431 M 0.0526 M
While working in a metal processing facility, Letlen had accidentally mixed two metal vatstogether creating an alloy. One vat was labeled for cadmium, while the other was not. It canbe assumed that these are of pure metal composition. To identify this metal, Letlen took 1.000 g of the homogenous alloy sample composed ofcadmium and the unknown metal, dissolved, and diluted it to exactly 100.0 mL in avolumetric flask. A 20.00-mL aliquot was taken and titrated this using 22.82 mL of 0.05000M EDTA. In a second 20.00-mL aliquot, the Cd was masked through the addition of HCN/NaCN buffer.The titration of the unknown metal in the aliquot required 15.13 mL of EDTA.MW: Cd (112.411 g/mol) a. Calculate the moles of Cd and the moles of unknown metal in the 20.00-mL aliquot.b. Calculate the moles of Cd and the moles of unknown metal in the sample.
One gram of sodium hydroxide (NaOH) is used to adjust the pH of an aqueous solution (200 gallons) thatcontains 10 lbs of finely ground rhodochrosite (MnCO3) ore. Does the NaOH raise or lower the solutionpH? What is the amount of NaOH added in lbs/ton? What is the molarity (mol/l) of the system? Assumingthe NaOH is completely soluble and the system is at room temperature, what is the solid-to-liquid ratio(wt%) of the system?
Calculate the gravimetric factor of the following. 2 Fe3O4 is sought(Analyte), 3 Fe2O3 is weighed (Precipitate)
1ml of 1mg/ml of diluted aspirin powder solution is titrated by 0.005M NaOH. Before titration, 5 ml ethanol, 14 ml CO2 free water, and 4 drops bromothymol blue indicator is added into diluted aspirin powder solution. Mass of 0.005M NaOH used is obtained by weight titration = 1.1384g . [Molar mass of aspirin =180.15]; for solution, 1g=1mL at 25 degree Celcius. Calculate the purity of the powder.
PS. Further values required for the solvings are give in the various situations below. (ANSWER) Situation: A community in a mountainous area of Bohol uses water collected from a nearby natural spring. A sample was submitted to a laboratory for the analysis of its total hardness. Required: SHOW YOUR COMPLETE CALCULATIONS. BASED ON THE IMAGE PROVIDED BELOW FOR THIS QUESTION: Calculate the amount of titrant used in each trial to reach endpoint. Report total hardness of the sample as mean ±sd. a. 250.0 mL of 500.0 ppm of CaCO3 solution from a primary standard (assume solvent is distilled water only). Answer : Mass of CaCO3 = 0.125 g b, The EDTA solution was standardized by titrating it with a 25.0 mL aliquot of the CaCO3 solution. How much of the titrant was consumed. Answer: Volume of EDTA consumed = 12.405 g c. Calculate the average titer (mg CaCO3/mL EDTA). Mass of CaCO3 in 25 mL CaCO3 solution: 0.0125 g Answer: 1.008 mg CaCO3/ mL EDTA
A piece of Gold weighing 12,359 Kg is suspected of being contaminated with Iron. To perform an instrumental analysis and To confirm whether or not it contains Fe, a portion of the sample (0.954 g) is taken from the piece and dissolved with 25 mL of aqua regia. Heats up For its complete dissolution, it is cooled and made up to 100 mL. A 10 mL aliquot is taken from this solution and made up to 50 mL. From This last solution is given the appropriate treatment to visualize Fe+2, for which the 1,10-phenanthroline reagent is added. (it forms a complex that is red in color) and is taken to a visible spectrophotometer and with a 12 mm cell a absorbance of 0.45. Previously, a calibration curve of Fe+2 was obtained under the same instrumental conditions obtaining the following data: (view table) Calculate the purity of the gold piece, assuming impurities only due to Fe.
A shipment of containing NaOH (40 g/mol) and Na2CO3 (106 g/mol) was declared to contain less than 10 % impurity. However, Noel is suspicious that the declared impurity is higher. Being the best and brightest employee of the year, Noel weighed 1.000 g sample, dissolved in 50.0 mL of distilled water and titrated with cold 0.5000 M HCl. With Phenolphthalein as indicator, the solution turns colorless after the addition of 30.00 mL of the acid. Methyl Orange is then added, and 5.00 mL more of the acid is required before this this indicator changes color. Calculate the following: a. Determine the volume of the acid to fully neutralize NaOH (final answer up to one decimal place) =