You took 25.00 mL of unknown water solution and titrated it with EDTA. The EDTA solution molarity was 0.01 M, and it took 16.50 mL to reach the end point. With the blank it took only 0.98 mL to reach end point. 15.52 mL of EDTA solution were used to titrate hardness that actually came from the unknown 1.552×10−4 moles of EDTA reacted with hardness-causing ions from the unknown sample 1.552×10−4 moles of hardness-causing ions were present in the unknown sample A) Assuming that the total hardness of water is due to CaCO3, how many grams CaCO3 does it correspond to? B) What is the total hardness of the unknown water in ppm CaCO3?

You took 25.00 mL of unknown water solution and titrated it with EDTA. The EDTA solution molarity was 0.01 M, and it took 16.50 mL to reach the end point. With the blank it took only 0.98 mL to reach end point. 15.52 mL of EDTA solution were used to titrate hardness that actually came from the unknown 1.552×10−4 moles of EDTA reacted with hardness-causing ions from the unknown sample 1.552×10−4 moles of hardness-causing ions were present in the unknown sample A) Assuming that the total hardness of water is due to CaCO3, how many grams CaCO3 does it correspond to? B) What is the total hardness of the unknown water in ppm CaCO3?

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter31: Introduction To Analytical Separations

Section: Chapter Questions

Problem 31.1QAP

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Five white, 500-mg uncoated ascorbic acid (AA) tablets with an average weight of 0.6100-g were pulverized in a mortar. A sample of the powdered ascorbic acid weighing 0.4610-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 46.73-mL of 0.0152 M 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 2.78-mL of 0.1047 M 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. None of the choices 349.7 mg 264.3 mg 462.7 mg
100 mL tap water is titrated with 20 mL of 0.02 M EDTA solution to determine the hardness of the water. The second 100 mL tap water is precipitated as CaC2O4 and removed by filtration and the filtrate is titrated with 8.0 mL of the same EDTA solution. What are the concentrations (as ppm) of Ca2+ (40.078 g/mol) and Mg2+ (24.305 g/mol) ions in the water? 2) 10 g of a solution, containing one or more of NaOH, Na3PO4, Na2HPO4, NaH2PO4, H3PO4 and HCl substances, is titrated with 1.0 M NaOH using the phenolphthalein indicator and 34.5 mL NaOH is used. Another 10 g mixture was titrated to reach the bromocresol green end point and 20.50 mL NaOH is used. What is the composition of the solution? What are the percentages of the species(H:1.0078, O:15.99, Na: 22.98, P:30.974, Cl:35.453)?
If you have a sample of 42.6 mg/L of calcium and 7.2 mg/L of magnesium, what concentration does the titrant have to have to spend 15.00 mL of EDTA and 25.00 mL of sample?
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
The solubility of borax, which is made up of sodium tetraborate (Na2B4O5(OH)4 8H2O), was analyzed. The dissolution of borax is: Na2B4O5(OH)4 • 8H2O(s) ⇌ 2 Na+(aq) + B4O5(OH)42–(aq) + 8 H2O(l) A 50 mL saturated solution was prepared. After filtration of solution, 5 mL aliquot was transferred to a flask and titrated using 0.432 M HCl. The endpoint was found to be 4.73 mL of the titrant. Tetraborate anion (B4O5(OH)42-) is a weak base which reacts with HCl like the following reaction: B4O5(OH)42–(aq) + 2 H+(aq) + 3 H2O(l) ⇌ 4 H3BO3(aq) What is Ksp expression for the dissolution? What is the tetraborate ions concentration in the filtrate? What is the molar solubility and Ksp of borax if the titration was done at room temperature (298 K)?
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Standardization of EDTA was done using MgSO4 standard wherein a 50-mL aliquot of solution obtained from 0.480 g MgSO4 in 500 mL needed 39.4 mL of the EDTA solution to reach the endpoint. Determine how many milligrams of CaCO3 will react per mL of this EDTA solution.
A sample of water from a river was analyzed by titrating a 125 mL aliquot with 0.0210 M EDTA, consuming 22.52 mL. Express the hardness of the water in ppm of CaCO3.
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An EDTA solution prepared from its disodium salt was standardized using 0.250-g primary standard CaCO3 (MW=100.087) and consumed 28.50 mL of the solution. The standard solution was used to determine the hardness of a 2.0 L sample of mineral water, which required 35.57 mL EDTA solution. Express the analysis in terms of ppm CaCO3
1. What is the MW of the analyte?2. What is the meq of the analyte?3. What will be the weight (in grams) of the analyte if the standardization is to be quartered?4. What will be Normality of the solution if 7.5ml of the titrant was consumed in the standardization?5. What is the average Normality if two or more trials were conducted with the values of 0.102N and 0.105N?
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