A salt sample was analyzed for its purity. A 0.5000 g sample was dissolved in water and diluted to 250 mL. From this solution, 25.00 mL was taken for analysis. To this aliquot, 20.00 mL of a 0.08735 M AgNO3 solution was added to precipitate the chloride. The excess AgNO3 required 12.45 mL of a 0.09473 M KSCN solution for back-titration. Calculate the purity of the salt sample as percent by mass of KCl (74.55 g/mol)

A salt sample was analyzed for its purity. A 0.5000 g sample was dissolved in water and diluted to 250 mL. From this solution, 25.00 mL was taken for analysis. To this aliquot, 20.00 mL of a 0.08735 M AgNO3 solution was added to precipitate the chloride. The excess AgNO3 required 12.45 mL of a 0.09473 M KSCN solution for back-titration. Calculate the purity of the salt sample as percent by mass of KCl (74.55 g/mol)

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.33QAP

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A solution containing chloride ion was analyzed by the Volhard method. A 50.00 mL sample containing chloride ion was treated with 25.00 mL of 0.2500 M silver nitrate. The precipitated AgCl was removed from the solution by filtration, and 1.00 mL of 0.1000 M Fe3+ was added to the filtrate. This new solution was then titrated with 10.67 mL of 0.2380 M KSCN. What is the concentration of chloride ion in the original solution?
A 0.1093-g sample of impure Na2CO3 was analyzed by the Volhard Method. After adding 50.00 mL of 0.06911 M AgNO3, the sample was back titrated with 0.05781 M KSCN, requiring 27.36 mL to reach the end point. Report the purity of Na2CO3sample.
A salt sample was analyzed for its purity. A 0.5000g sample was dissolved in water and diluted to 250.0mL. From this solution, 25.00mL was taken for analysis. To this aliquot, 20.00mL of a 0.08735M AgNOg solution was added to precipitate the chloride. The excess AgNO, required 12.45mL of a 0.09473M KSCN solution for back-titration. Calculate the purity of the salt sample as percent by mass of KCI (74.55 g/mol). (Answer: 84.63% KCI)
A 1.250 g sample of cheese was subjected to a Kjeldahl analysis to determine the amount of protein. The sample was digested, the nitrogen is oxidized to NH₄⁺, and was then converted to NH₃ with NaOH, and distilled into a collection flask containing 50.00 mL of 0.1050 M HCl. The excess HCl is back titrated with 0.1175 M NaOH, this required 21.65 mL to reach the bromothymol blue end point. A. How many moles of N is present in the cheese sample? B. Report the %N of the cheese sample. C. Report the %protein of the cheese sample, assuming that there are 6.4 grams of protein for every gram of nitrogen
A 1.250 g sample of cheese was subjected to a Kjeldahl analysis to determine the amount of protein. The sample was digested, the nitrogen is oxidized to NH₄⁺, and was then converted to NH₃ with NaOH, and distilled into a collection flask containing 50.00 mL of 0.1050 M HCl. The excess HCl is back titrated with 0.1175 M NaOH, this required 21.65 mL to reach the bromothymol blue end point. What is the reaction for the digestion of the limestone sample A. 2 NaOH + CaCO₃ ⇌ Na₂CO₃ + Ca(OH)₂ B. 2 HCl + CaCO₃ ⇌ CaCl₂ + H₂O + CO₂ C. CaCO₃ ⇌ CaO + CO₂ D. NaOH + HCl ⇌ NaCl + H₂O
A 1.250 g sample of cheese was subjected to a Kjeldahl analysis to determine the amount of protein. The sample was digested, the nitrogen is oxidized to NH₄⁺, and was then converted to NH₃ with NaOH, and distilled into a collection flask containing 50.00 mL of 0.1050 M HCl. The excess HCl is back titrated with 0.1175 M NaOH, this required 21.65 mL to reach the bromothymol blue end point. What is the reaction for the back titration for this analysis? a. NH₄⁺ + NaOH ⇌ NH₃ + H₂O + Na⁺ b. NaOH + HCl ⇌ NaCl + H₂O c. NH₃ + HCl ⇌ NH₄⁺ + Cl⁻ d. N₂ + 3 H₂ ⇌ 2 NH₃ How many moles of N is present in the cheese sample? a. 544 x 10⁻³ b. 706 x 10⁻³ c. 250 x 10⁻³ d. 794 x 10⁻³ Report the %N of the cheese sample. a. 851% b. 884% c. 033% d. 736%
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A 1.250 g sample of cheese was subjected to KKjeldahl analysis to determine the amount of protein. the sample was digested and the nitrogen is oxidized to NH4+ and was then converted to NH3 with NaOH., and distilled into a collection flask containing 50.00 mL of .1050 M HCl. The excess HCl is back titrated with .1175M NaOH, this required 21.65 mL to reach the bromothymol blue endpoint. What is the reaction for the back titration for this analysis and the %N of cheese sample.
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