3. A 100.0 mL sample of ground water was treated to convert the iron present to Fe2+. Addition of 25.00 mL of 0.002412 M K2Cr2O7 resulted in the reaction below. 6Fe2+ + Cr2O72 - + 14H+ → 6Fe3+ + 2Cr3+ + 7H2O The excess K2Cr2O7 was back-titrated with 8.12 mL of 0.00859 M Fe2+ solution. What is the concentration of Fe in the sample in parts per million?

3. A 100.0 mL sample of ground water was treated to convert the iron present to Fe2+. Addition of 25.00 mL of 0.002412 M K2Cr2O7 resulted in the reaction below. 6Fe2+ + Cr2O72 - + 14H+ → 6Fe3+ + 2Cr3+ + 7H2O The excess K2Cr2O7 was back-titrated with 8.12 mL of 0.00859 M Fe2+ solution. What is the concentration of Fe in the sample in parts per million?

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.34QAP

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2. 100.0-mL sample of spring water was treated to convert any iron present to Fe2*. Addition of 25.00 mL of 0.002107 M K2Cr207 resulted in the reaction 6FE2+ + Cr20,2- + 14H* ® 6F€³+ + 2Cr3+ + 7H2O The excess K2C1207 was back-titrated with 7.47 mL of a 0.00979 M Fe2+ solution. Calculate iron concentration (molarity) in the sample.
A 100.0-mL sample of spring water was treated to convert any iron present to Fe21. Addition of25.00-mL of 0.002517 M K2Cr2O7 resulted in the reaction6Fe2+ + Cr2O7 2- + 14H+ → 6Fe3+ + 2Cr3+ + 7H2OThe excess K2Cr2O7 was back-titrated with 8.53 mL of 0.00949 M Fe2+ solution. Calculate the concentration of iron in the sample in parts per million.
To analyze the amount of iron (Fe; Mw = 55.85 g/mol) contained in an ore sample, the sample was digested with acid and diluted to 50 mL with water. This solution was then treated with 25.00 mL of 0.2922 M EDTA. The excess EDTA was back titrated with 6.47 mL of 0.0843 M Zn2+ to reach the equivalence point. How many grams of Fe contained in the ore sample?
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A Chemist collected a 0.4891-g sample of an ore for Fe determination by a redox titration with K2Cr2O7.The ore was carefully crushed prior to weighing and dissolved in HCl and using a Jones reductor the ironin the sample was brought into the +2 oxidation state. After titration with diphenylamine sulfonic acid,itrequired 36.92 mL of 0.02153 M K2Cr2O7 to reach the end point. Calculate the iron content of the ore as%w/w Fe2O3
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