A 0. 750 g sample of flour was subjected to a Kjeldahl analysis. The ammonia formed after digestion was distilled into 30. 00 mL of 0. 0500 M HCI. The excess HCI was back titrated with 6. 50 mL of 0.0400 M NaOH. Calculate the following parameters in the flour: a. percent N b. percent protein (factor = 5. 70) This problem involves back titration. Solve for the mole of acid reacted with the ammonia. Use the mole of acid to solve the grams of N and protein, use those values to solve the % w/w.

A 0. 750 g sample of flour was subjected to a Kjeldahl analysis. The ammonia formed after digestion was distilled into 30. 00 mL of 0. 0500 M HCI. The excess HCI was back titrated with 6. 50 mL of 0.0400 M NaOH. Calculate the following parameters in the flour: a. percent N b. percent protein (factor = 5. 70) This problem involves back titration. Solve for the mole of acid reacted with the ammonia. Use the mole of acid to solve the grams of N and protein, use those values to solve the % w/w.

Chemical Principles in the Laboratory

11th Edition

ISBN:9781305264434

Author:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Publisher:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Chapter24: The Standardization Of A Basic Solution And The Determination Of The Molar Mass Of An Acid

Section: Chapter Questions

Problem 3ASA: A 0.3012g sample of an unknown monoprotic acid requires 24.13mL of 0.0944MNaOH for neutralization to...

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A 0.3012g sample of an unknown monoprotic acid requires 24.13mL of 0.0944MNaOH for neutralization to a phenolphthalein end point. There are 0.32mL of 0.0997MHCl used for back titration. a. How many moles of OH are used? How many moles of H+ from HCl? _______moles OH ________moles H+ b. How many moles of H+ are there in the solid acid? Use Eq.5. ____________ moles H+ in solid c. What is the molar mass of the unknown acid? Use Eq.4. ____________ g/mol
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A 0.5131-g sample containing KBr is dissolved in 50 mL of distilled water. Titrating with 0.04614 M AgNO3 requires 25.13 mL to reach the Mohr end point. A blank titration requires 0.65 mL to reach the same end point. Report the %w/w KBr in the sample.
A multivitamin sample has a label claim of 500 mg ascorbic acid (176.12 g/mol). According to quality assurance guidelines for stability, it has an acceptable range of 90.0%-110.0% of the label claim. After production, the multivitamin was analyzed through acid-base titration, and the sample needed 25.40 mL of a 0.1101 M NaOH titrant to reach the end point. After 3 months, the same multivitamin was analyzed again, and this time 23.34 mL of the same 0.1101 M titrant was used. After 6 months, the same multivitamin was analyzed again, and this time, 22.48 mL of the same 0.1101 M NaOH titrant was needed to reach the end point. If the multivitamin was manufactured on March 2021, when is its most likely expiration date? June 2021 September 2021 December 2021 March 2022
A multivitamin sample has a label claim of 500 mg ascorbic acid (176.12 g/mol). According to quality assurance guidelines for stability, it has an acceptable range of 90.0%-110.0% of the label claim. After production, the multivitamin was analyzed through acid-base titration, and the sample needed 25.40 mL of a 0.1101 M NaOH titrant to reach the end point. After 3 months, the same multivitamin was analyzed again, and this time 23.34 mL of the same 0.1101 M titrant was used. After 6 months, the same multivitamin was analyzed again, and this time, 22.48 mL of the same 0.1101 M NaOH titrant was needed to reach the end point. 1. How many mg of ascorbic acid is present in the sample after production? 2. How many mg of ascorbic acid are present in the 3 month old sample? 3. How many mg of ascorbic acid are present in the 6 month old sample? 4. If the multivitamin was manufactured on March 2021, when is its most likely expiration date? a. June 2021 b. September 2021 c. December 2021…
A multivitamin sample has a label claim of 500 mg ascorbic acid (176.12 g/mol). According to quality assurance guidelines for stability, it has an acceptable range of 90.0%-110.0% of the label claim. After production, the multivitamin was analyzed through acid-base titration, and the sample needed 25.40 mL of a 0.1101 M NaOH titrant to reach the end point. After 3 months, the same multivitamin was analyzed again, and this time 23.34 mL of the same 0.1101 M titrant was used. After 6 months, the same multivitamin was analyzed again, and this time, 22.48 mL of the same 0.1101 M NaOH titrant was needed to reach the end point.
A multivitamin sample has a label claim of 500 mg ascorbic acid (176.12 g/mol). According to quality assurance guidelines for stability, it has an acceptable range of 90.0%-110.0% of the label claim. After production, the multivitamin was analyzed through acid-base titration, and the sample needed 25.40 mL of a 0.1101 M NaOH titrant to reach the end point. After 3 months, the same multivitamin was analyzed again, and this time 23.34 mL of the same 0.1101 M titrant was used. After 6 months, the same multivitamin was analyzed again, and this time, 22.48 mL of the same 0.1101 M NaOH titrant was needed to reach the end point. A. How many mg of ascorbic acid is present in the sample after production? 521.0 mg 506.7 mg 492.53 mg 488.12 m B. How many mg of ascorbic acid are present in the 3 month old sample? 492.53 mg 488.12 mg 452.58 mg 435.91 mg C. How many mg of ascorbic acid are present in the…
Chemistry A 1.899 g of an oat cereal is determined by Kjeldahl analysis. The sample is digested with H2SO4, the resulting solution made basic with NaOH, and the NH3 distilled into 45.00 mL of 0.4325 M HCl. The excess HCl is back titrated with 27.00 mL of 0.670 M NaOH using mixed indicator. What is the %w/w protein in the sample if the protein grains averages 12.90% w/w N?
An unknown sample containing mixed alkali (NaOH / NaHCO3 / Na2CO3) was analyzed using the double titration method. A 250-mg sample was dissolved in 250-mL CO2 free water. A 20.0-mL aliquot of this sample required 11.3-mL of 0.009125M HCl solution to reach the phenolphthalein endpoint. Another 20.0-mL aliquot of the sample was titrated to the bromocresol green endpoint using 31.1-mL of the standard acid. What is/are the component(s) of the sample? How many mmol of the components are there in the original solid sample?
A neutralization titration was performed to determine the benzoic acid (C6H5COOH) in a 500 mL sample. In order to prepare the titrant, 5 grams of NaOH was weighed and dissolved in 1 L of distilled water. 10 mL of the sample was titrated with the NaOH solution after adding an appropriate indicator to the erlenmeyer. Four trials were done and 2.5 mL, 2.7 mL, 2.6 mL and 2.4 mL of NaOH were consumed. What is the mass of benzoic acid as gram in the sample. (C:12 g/mol, H:1 g/mol, O:16 g/mol, Na: 23 g/mol)
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