In an analytical laboratory that analyzes BOD, the titrant solution of sodium thiosulphate must be standardized every 3 days. The standardized concentration can be determined with the help of a standard potassium dichromate solution. This is an oxidation and reduction reaction, as well as "lodometric reaction". The reactions of the process are: 6 KI + 14 HCI + K,Cr,0,→2 Crcl, + 3 1 + 7 H,0 + 8 KCI 2 Na,s,0, + l2 → Na,s,0,+2 Nal Given the standardization data in the table below, determine the missing values as indicated by the question mark. Number of Volume of 0.1065Volume of Na,S,0, used Standardized concentration to titrate K,Cr,07, mL observation M K,Cr,0,, mL of Na,s,0, M 01 10.0 6.65 ? 02 10.0 7.10 03 10.0 6.80 04 10.0 7.00 Mean: ? Standard deviation: ?

In an analytical laboratory that analyzes BOD, the titrant solution of sodium thiosulphate must be standardized every 3 days. The standardized concentration can be determined with the help of a standard potassium dichromate solution. This is an oxidation and reduction reaction, as well as "lodometric reaction". The reactions of the process are: 6 KI + 14 HCI + K,Cr,0,→2 Crcl, + 3 1 + 7 H,0 + 8 KCI 2 Na,s,0, + l2 → Na,s,0,+2 Nal Given the standardization data in the table below, determine the missing values as indicated by the question mark. Number of Volume of 0.1065Volume of Na,S,0, used Standardized concentration to titrate K,Cr,07, mL observation M K,Cr,0,, mL of Na,s,0, M 01 10.0 6.65 ? 02 10.0 7.10 03 10.0 6.80 04 10.0 7.00 Mean: ? Standard deviation: ?

Chemistry: Principles and Reactions

8th Edition

ISBN:9781305079373

Author:William L. Masterton, Cecile N. Hurley

Publisher:William L. Masterton, Cecile N. Hurley

Chapter4: Reactions In Aqueous Solution

Section: Chapter Questions

Problem 71QAP: Calcium in blood or urine can be determined by precipitation as calcium oxalate, CaC2O4. The...

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The iron content of hemoglobin is determined by destroying the hemoglobin molecule and producing small water-soluble ions and molecules. The iron in the aqueous solution is reduced to iron(II) ion and then titrated against potassium permanganate. In the titration, iron(ll) is oxidized to iron(III) and permanganate is reduced to manganese(II) ion. A 5.00-g sample of hemoglobin requires 32.3 mL of a 0.002100 M solution of potassium permanganate. The reaction with permanganate ion is MnO4(aq)+8H+(aq)+5Fe2+(aq)Mn2+(aq)+5Fe3+(aq)+4H2O What is the mass percent of iron in hemoglobin?
Triiodide ions are generated in solution by the following (unbalanced) reaction in acidic solution: IO3(aq) + I(aq) I3(aq) Triiodide ion concentration is determined by titration with a sodium thiosulfate (Na2S2O3) solution. The products are iodide ion and tetrathionate ion (S4O6). a. Balance the equation for the reaction of IO3 with I ions. b. A sample of 0.6013 g of potassium iodate was dissolved in water. Hydrochloric acid and solid potassium iodide were then added. What is the minimum mass of solid KI and the minimum volume of 3.00 M HQ required to convert all of the IO3 ions to I ions? c. Write and balance the equation for the reaction of S2O32 with I3 in acidic solution. d. A 25.00-mL sample of a 0.0100 M solution of KIO. is reacted with an excess of KI. It requires 32.04 mL of Na2S2O3 solution to titrate the I3 ions present. What is the molarity of the Na2S2O3 solution? e. How would you prepare 500.0 mL of the KIO3 solution in part d using solid KIO3?
Calcium in blood or urine can be determined by precipitation as calcium oxalate, CaC2O4. The precipitate is dissolved in strong acid and titrated with potassium permanganate. The equation for reaction is 2MnO4(aq)+6H+(aq)+5H2C2O4(aq)2Mn2+(aq)+10CO2(g)+8H2O A 24-hour urine sample is collected from an adult patient, reduced to a small volume, and titrated with 26.2 mL of 0.0946 M KMnO4. How many grams of calcium oxalate are in the sample? Normal range for Ca2+ output for an adult is 100 to 300 mg per 24 hour. Is the sample within the normal range?
The blood alcohol (C2H5OH) level can be determined by titrating a sample of blood plasma with an acidic potassium di-chromate solution, resulting in the production of Cr3+ (aq) and carbon dioxide. The reaction can be monitored because the dichromate ion (Cr2O72) is orange in solution, and the Cr3+ ion is green. The balanced equations is 16H+(aq) + 2Cr2O72(aq) + C2H5OH(aq) 4Cr4+(aq) + 2CO2(g) + 11H2O(l) This reaction is an oxidationreduction reaction. What species is reduced, and what species is oxidized? How many electrons are transferred in the balanced equation above?
4.112 A metallurgical firm wishes to dispose of 1300 gallons of waste sulfuric acid whose molarity is 1.37 M. Before disposal, it will be reacted with calcium hydroxide (slaked lime), which costs $0.23 per pound. (a) Write the balanced chemical equation for this process. (b) Determine the cost that the firm will incur from this use of slaked lime.
What volume of 0.0521 M Ba(OH)2 is required to neutralize exactly 14.20 mL of 0.141 M H3PO4? Phosphoric acid contains three acidic hydrogens.
One method for determining the purity of aspirin (C9H8O4) is to hydrolyze it with NaOH solution and then to titrate the remaining NaOH. The reaction of aspirin with NaOH is as follows: A sample of aspirin with a mass of 1.427 g was boiled in 50.00 mL of 0.500 M NaOH. After the solution was cooled, it took 31.92 mL of 0.289 M HCl to titrate the excess NaOH. Calculate the purity of the aspirin. What indicator should be used for this titration? Why?
Write the net ionic equation for the reaction, if any, that occurs on mixing (a) solutions of sodium hydroxide and magnesium chloride. (b) solutions of sodium nitrate and magnesium bromide. (c) magnesium metal and a solution of hydrochloric acid to produce magnesium chloride and hydrogen. Magnesium metal reacting with HCl.
The equivalence point for the titration of a 25.00-mL sample of CSOH solution with 0.1062 M HNO3 is at 35.27 mL. What is the concentration of the CsOH solution?
In order to determine the purity of ammonium sulfate, a sample with a mass of 0.850 g is dissolved in KOH. The equation for the reaction that takes place is NH4+(aq)+OH(aq)NH3(aq)+H2OThe ammonia liberated is distilled into a flask that contains 50.00 mL of 0.250 M HCI. Not all the HCI is consumed. The excess HCI reacts with 17.3 mL of 0.120 M NaOH. What is the mass percent of (NH4)2SO4 in the sample?
An aqueous sample is known to contain either Mg2+ or Ba2+ ions. Treatment of the sample with Na2CO3 produces a precipitate, but treatment with ammonium sulfate does not. Use the solubility rules (see Table 4.1) to determine which cation is present.
1. Sometimes a reaction can fall in more than one category. Into what category (or categories) does the reaction of Ba(OH)2(aq) + H+PO4(aq) fit? acid-base and oxidation-reduction oxidation-reduction acid-base and precipitation precipitation