The protein in a 1.2846-g sample of an oat cereal is determined by the Kjeldahl procedure for organic nitrogen. The sample is digested with H2SO4, the resulting solution made basic with NaOH, and the NH3 distilled into 50.00 mL of 0.09552 M HCl. The excess HCl is then back titrated using 37.84 mL of 0.05992 M NaOH. Given that the protein in grains averages 17.54% w/w N, report the %w/w protein in the sample of cereal.

Excess solid Ni(OH)2 was added to water and the resulting solution was allowed to stand for several days. The solution was then filtered to remove excess solid Ni(OH)2. A 0.250 L aliquot of the solution was then titrated with 10.54 mL of a standardized 0.000500 M HCl solution. What is the Ksp of Ni(OH)2?

16. 25.0 mL of 1.074 M HCI is added to 1.13 g sample of eggshell. Calcium carbonate in the egg shells reacts with HCI according to the following equation. CaCO3 + 2HCl CaCl₂ + H₂O + CO₂ The excess HCl is titrated with 22.5 mL of 0.248 M NaOH to the end point. Calculate the percent of calcium carbonate in the egg shell

A 0.5145-g sample of a water-soluble fertilizer was dissolved and analyzed for nitrogen using the Kjeldahl method. After digestion, the distilled ammonia was collected in 100 mL of 0.1334 M boric acid. This solution required 29.38 mL of 0.202 M HCl for titration to the methyl red end point. Calculate the % N (AW =14 g/mol) in the fertilizer. Type the numerical answer only.

The protein in a 0.2976 -g sample of cheese is determined by the Kjeldahl method. The sample is digested with H2SO4, the resulting solution made basic with NaOH, and the ammonia distilled into 50.00 mL of 0.09756 M HCl. The excess HCl is then back titrated using 39.87 mL of 0.05345 M NaOH. Calculate the % N and % protein of the sample.

You are running an acid-base titration with hydrochloric acid and calcium hydroxide.  The calcium hydroxide is your titrant; it has a known concentration of 0.0891 M.  You have added 25.0 mL of the hydrochloric acid solution to an Erlenmeyer flask along with 2 drops of phenolphthalein (fee’-nol-thay-leen) indicator.  To begin your first trial, you fill a clean 50 mL buret with the calcium hydroxide solution.  Your starting volume is 0.25 mL. After the addition of solution from the buret, you see a color change in the flask, and the end point of the reaction is reached.  You note the final volume in the buret to be 18.75 mL. You begin again for your second titration trial.  You add 24.8 mL of the hydrochloric acid solution to a clean flask along with 2 drops of indicator.  You refill the buret to an initial volume of 1.42 mL.  When the reaction is complete, you note the final volume in the buret at 16.74 mL. Then you complete a third trial.  You add 25.6 mL of hydrochloric acid solution…

2. A 0.4912-g sample of a petroleum product was burned in a tube furnace, and the SO2 produced was collected in H2O2. SO2(g) + H2O2 → H2SO4 A 25.00-mL portion of 0.00873 M NaOH was introduced into the solution of H2SO4, following which the excess base was back-titrated with 15.17 mL of 0.01102 M HCl. Calculate the sulfur concentration in parts per million.

For breakfast, the nihilistic Rick Sanchez ate 100 g of cereal mixed with 20 g of milk. A 1.500 g sample of the same cereal was analyzed using the Kjeldahl method, and the liberated NH3 was distilled into 50 mL of a 0.0227 M HCl solution, and back-titrated with 2.85 mL of 0.0112 M NaOH solution. A 1.100 g sample of milk was also analyzed, and the liberated NH3 was distilled into 55 mL of a 0.0234 M HCl solution, and back-titrated with a 3.10 mL of 0.0121 M NaOH.   Use the values: MM N=14.07 g/mol. meat= 6.25 dairy= 6.38 cereal= 5.70   What is the % protein in the cereal sample? What is the % protein in the milk sample?

A sample weighing 10.91 g containing an unknown amount of H3PO4 was diluted with water and titrated with a standardized concentration of 0.7255 M NaOH. The endpoint was reached after 27.03 mL of the titrant was added. What is the % H3PO4 (97.994 g/mole) in the sample?   H3PO4  +  2 NaOH --> Na2HPO4 + 2H2O   ROUND OFF FINAL ANSWER TO FOUR (4) SIG FIGS

2. Using the procedure described in this module, a student determined the percent KHP in an impure sample of KHP. A 3.150-g sample of impure KHP required 41.50 mL of 0.1352M NaOH solution for titration. (a) Calculate the number of moles of NaOH required for the titration. (b) Calculate the number of moles of KHP present in the impure sample of KHP. (c) Calculate the number of grams of KHP present in the impure sample. (d) Calculate the percent of KHP in the impure sample, using Equation 8. Equation 8: percent KHP in the impure sample, % = ( mass of KHP in the sample,g/ mass of sample analyzed, g) (100%)