Bulletin - Bureau of Chemistry, Edicions 153-166

U.S. Government Printing Office, 1912

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Pàgina 31 - Gradually raise the temperature and when danger (if any) from frothing has ceased, distil until 95 cc. of distillate is obtained, and titrate as usual. In cases where a tendency to froth is noticed, lengthen the digestion period and no trouble will be experienced when the distillation is begun. During the digestion, gently rotate the flask occasionally, particularly if the material shows a tendency to adhere to the sides (it is recommended that as nearly as possible 90 minutes be taken for the digestion...
Pàgina 162 - That the collector shall designate on the invoice at least one package of every invoice, and one package at least of every ten packages of goods, wares, or merchandise, and a greater number, should he or either of the appraisers deem it necessary, imported into such port, to be opened, examined, and appraised...
Pàgina 158 - Weigh 10 grams of the sample into a shaking bottle, add 200 cc of distilled water, and shake for 15 minutes. Filter the extract through a folded filter and take an aliquot of 20 cc (equal to 1 gram of the sample) for the titration.
Pàgina 187 - Filter and keep in a glass-stoppered bottle. Standard solution of sodium nitrite: To a cold solution of about 2 grams of sodium or potassium nitrite in 50 cc of water add a solution of silver nitrate as long as a precipitate appears. Decant the liquid and thoroughly wash the precipitate with cold water. Dissolve in boiling water. On cooling the silver nitrite is precipitated.
Pàgina 21 - If it consists in whole or in part of a filthy, decomposed, or putrid animal or vegetable substance, or any portion of an animal unfit for food, whether manufactured or not, or if it is the product of a diseased animal, or one that has died otherwise than by slaughter. Sec. 8. That the term
Pàgina 9 - Introduce 10 cubic centimeters of a 50% honey solution into a test tube and add 5 cubic centimeters of ether. Shake gently and let stand for some time until the ether layer is clear. Transfer 2...
Pàgina 70 - ... acid, allow to cool to room temperature, and make up to mark with distilled water. Filter through a starch-free filter paper and after neutralizing determine the dextrose present in a 50 cc portion of the filtrate with Fehling's solution, using Low's method, Bulletin 107, Revised, page 241, for the determination of the copper in the cuprous oxid precipitate. Dextrose times 0.9 equals starch.
Pàgina 15 - Evaporate the filtrate to dryness in porcelain ; when cold add 2 cc of phenol disulphonic acid reagent,1 rubbing with a glass rod to insure intimate contact. Dilute with distilled water and add slowly ammonium hydroxid until the maximum color is developed. Transfer to a colorimetric cylinder, filtering if necessary, and compare with a standard potassium nitrate solution ! (containing 0.01 mg of nitrogen as nitrate in 1 cc) which has been treated in like manner with phenol disulphonic acid reagent....

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