MasteringChemistry: Post Lecture Ho Chapter 04 Secure https// session masteringc
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MasteringChemistry: Post Lecture Ho Chapter 04 Secure https// session masteringchemistry.com/myct/itemview?assignmentProblemiD-9788653 Post Lecture Homework Chapter 04 Redox Titration of Bleach K 11 of 19 Constants Periodic Table Analysis of bleach involves two reactions: First, bleach is reacted in acid solution with excess iodide anion to produce yellow-colored A sample of a new cleaning product, "Joe's Famous Bleach Cleaner," with a mass of 46.0 g was diluted with an acetic acid solution containing excess I.A small amount of starch indicator solution was then added, turning the solution a deep bluish-purple. The solution was then titrated with 0.390 M sodium thiosulfate, Na2S203, containing the ion S20s.A volume of 38.0 mL of sodium thiosulfate, the titrant, was needed to tun the solution colorless redox CIO- +2H++21I2+Cl +H20 Then, to determine how much of the iodine was formed, the solution is titrated with sodium thiosulfate solution PartA 12 + 2S2032-21-+84062- s the percentage composition by mass of NaCIO in the bleach product? A bit of starch is added to the titration reaction Starch is intensely blue in the presence of I2. The solution thus turns from deep blue to colorless at the Express your answer to three significant figures and include the appropriate units. View Available Hint(s) e point Value UnitsExplanation / Answer
calculate the moles of S2O3 :
moles = molarity * volume
moles = 0.39 M * 0.038 L = 0.01482 moles
You require 2 moles of S2O3 for every mole of I2
moles of I2 = 0.01482 / 2 = 0.00741 moles of I2
this amount is equal to the moles of ClO-
moles of ClO- = 0.00741
from this point we can calculate the masses, molar mass of naclo = 74.44
mass of NaClO = 0.00741 * 74.44 = 0.5516 grams
the mass of the ssample is 46 grams so
% = 0.5516 * 100 / 46 = 1.2 %
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