1. The quantity of organically bound nitrogen (org-N) released by acid digestion is referred to as...

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1. The quantity of organically bound nitrogen (org-N) released by acid digestion is referred to as Kjeldahl nitrogen. One method used to determine the Kjeldahl nitrogen content involves a back titration and is outlined below. a) A 10.00 mL sample is diluted to 100 mL with distilled water. b) A 25.00 mL aliquot of this diluted sample is pipetted into a digestion flask. Concentrated H₂SO4 and H₂O₂ are added and the solution is heated for 45 mins (digestion). Under these conditions, the organic molecules are broken down and all the organic nitrogen is converted to NH4*. c) Concentrated NaOH is added to neutralize the excess H₂SO4 and to convert the NH4 to NH3, which is distilled into a flask containing 50.00 mL of 0.1011 N H₂SO4. d) The excess H₂SO4 was determined by titration with 5.12 mL of 0.1266 N NaOH. What is the mass of Kjeldahl nitrogen in the orignal sample in mg/L? 1. The quantity of organically bound nitrogen (org-N) released by acid digestion is referred to as Kjeldahl nitrogen. One method used to determine the Kjeldahl nitrogen content involves a back titration and is outlined below. a) A 10.00 mL sample is diluted to 100 mL with distilled water. b) A 25.00 mL aliquot of this diluted sample is pipetted into a digestion flask. Concentrated H₂SO4 and H₂O₂ are added and the solution is heated for 45 mins (digestion). Under these conditions, the organic molecules are broken down and all the organic nitrogen is converted to NH4*. c) Concentrated NaOH is added to neutralize the excess H₂SO4 and to convert the NH4 to NH3, which is distilled into a flask containing 50.00 mL of 0.1011 N H₂SO4. d) The excess H₂SO4 was determined by titration with 5.12 mL of 0.1266 N NaOH. What is the mass of Kjeldahl nitrogen in the orignal sample in mg/L?

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