Erlenmeyer flask

“ Immediately pipet 1.0 mL of acetaldehyde into the cold flask, reseal the flask and allow it to warm to room temperature. e. Reweigh the flask and subtract the tare weight from the weight of the reweighed flask to determine the weight of acetaldehyde added. f. Dilute the contents of the flask to the mark with toluene. g. Store the stock standards in a freezer. Prepare fresh stock standards every 10 days. APPENDIX B: PREPARATION OF XAD-2 SORBENT COATED WITH 2-HMP Weigh 125 g of crude XAD-2 adsorbent into a 1-L Erlenmeyer flask. ”

“ Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.05 and 0.2 L/min for a total sample size of 3 to 16 L. Cap the samplers with plastic (not rubber) caps and pack securely for shipment.
SAMPLE PREPARATION: 5. 6. 7.
Transfer the glass wool plug and front section of silica gel to a 50-mL Erlenmeyer flask. Transfer the backup sorbent section to another flask. Pipet 25 mL 50% aqueous methanol into each flask. Shake each flask occasionally over a 30-min period. Analyze samples within 1 day.
CALIBRATION AND QUALITY CONTROL: 8. ”

“ Erlenmeyer flasks, cover them with watch-glasses, and bring the acid just to boiling. Remove them from the flame and drop in the portions of wire, taking great care to avoid loss of liquid during solution. Boil for two or three minutes, keeping the flasks covered (Note 1) , then wash the sides of the flasks and the watch-glass with a little water and add stannous chloride solution to the hot liquid !from a dropper! until the solution is colorless, but avoid more than a drop or two in excess (Note 2) . Dilute with 150 cc. of water and cool !completely!. When cold, add rapidly about 30 cc. ”

“ The conditions necessary for success are— (1) that the apparatus should be in total darkness; [314] and (2) that there should be no substance present, such as alcohol or ammonia, [315] which, distilling over with the phosphorus-vapour, could destroy its luminosity. A convenient apparatus, and one certain to be in all laboratories, is an ordinary Florence flask, containing the liquid to be tested, fitted to a glass Liebig’s condenser, supported on an iron sand-bath (which may, or may not, have a thin layer of sand) , and heated by a Fletcher’s low temperature burner. ”

“ It rattles away like a valve chattering, because the steam rising from the boiling water sends the valve up and down, and forces itself out, and so makes it clatter. You can very easily perceive that the flask is quite full of steam, or else it would not force its way out. You see, also, that the flask contains a substance very much larger than the water, for it fills the whole of the flask over and over again, and there it is blowing away into the air ”

“ DETERMINATION OF CALCIUM PROCEDURE.—To the combined filtrates from the double precipitation of the hydroxides just described, add 5 cc. of dilute ammonium hydroxide (sp. gr. 0.96) , and transfer the liquid to a 500 cc. graduated flask, washing out the beaker carefully. Cool to laboratory temperature, and fill the flask with distilled water until the lowest point of the meniscus is exactly level with the mark on the neck of the flask. ”

“ Care must be taken that no particle of the sugar or solution is lost. To determine if all the sugar is dissolved, the flask is held above the level of the eye, in which position any undissolved crystals can be easily seen at the bottom. The character of the solution is now observed. If it be colorless or of a very light straw color, and not opalescent, so that it will give a clear transparent liquid on filtration through paper, the volume is made up directly with water to the 100 c.c. ”

“ The mixture first assumes a milky appearance, but after a little while, the salt dissolves, forming a coffee-colored solution, and gases are disengaged in abundance. When the salt is completely dissolved, the solution is found to contain ferrocyanide (red prussiate) of potassium, mixed with nitroprusside and nitrate of the same base. It is then immediately decanted into a large flask, and heated over the water-bath. It continues to evolve gas, and after awhile, no longer yields a dark blue precipitate with ferrous salts, but a dark green or slate-colored precipitate. ”

“ Pipet a sample aliquot estimated to contain 0.5 to 2.5 μg CN - into a 25-mL volumetric flask. Alternately, to cover an unknown sample concentration range, pipet 0.5-, 1.00-, and 3.00-mL aliquots into separate 25-mL vol. flasks for each field sample. Larger or smaller aliquots may be taken, based on prior knowledge of expected analyte level. Pipet 0.5 mL 0.1 N NaOH into a 25-mL volumetric flask for reagent blank. Add one drop phenolphthalein solution to each standard or sample. NOTE: Add a little deionized-distilled water to increase volume for easier mixing. ”

“ It permits the air to pass through and arrests all floating particles and, therefore, does not allow dust or germs to pass through with the air. A flask, or test-tube, is partly filled with an organic infusion; the latter is boiled and, while boiling, a plug of cotton-wool is pushed into the mouth of the vessel. On cooling, the air passes through this plug, but the smallest solid particles are caught in the meshes of the cotton-wool. Organic fluids treated in this way have been known for years to show no sign of microscopic life. ”

“ Some manufacturers who prepare their own pulp carry the concentration between 1.030 and 1.033. The method of obtaining this density is to use flasks graduated to hold 500 or 1000 grams of water at 200 degrees F., fill them with the hot pulp and weigh at once. For each flask there should be a proper counterpoise, and the balance be sensitive and weigh in grams. If the 1000-gram flask be used, the specific gravity will be the same as the weight of the pulp. With a valve funnel the flask may be filled level full and the weight taken in less than thirty seconds. ”

“ When the exhaustion « 106 » is complete (when a drop of petroleum-ether from the leather leaves no grease when allowed to evaporate on a clean glass) , the upper part of the apparatus is removed, and the ether is distilled off. If the flask has been previously weighed, it is maintained in an air-bath at 212°-248° F. (100°-120° C.) for some hours, allowed to cool, and weighed, when the gain of weight is the grease and oil. Paraffin would also be extracted and reckoned, and probably traces of resin if present. ”

“ Flamborough noticed a conical flask containing some limpid liquid, and a stoppered bottle. Markfield clamped a dropping funnel, also containing a clear liquid, so that its spout entered the conical flask; and by turning the tap of the funnel slightly, he allowed a little of the contents to flow down into the flask.
“I hope the smell doesn't trouble you,” he said, in a tone of sour apology. “It's the triethylamine I'm mixing with the tetranitromethane in the flask. Rather a fishy stink it has.” ”

“ Obtain an olive-oil flask, the glass of which must be colorless. In default of an oil-flask, a large test-tube may be employed. Put into it a small quantity of solid iodine (procurable at the chemist's and very cheap) , then lightly stop the mouth of the flask or test-tube with some cotton-wool, but not hermetically, and hold it slantwise over the flame of a spirit-lamp. The heat will soon dissolve the iodine, which will next turn into a most beautiful violet-colored vapor, completely filling the glass, and disappearing again as the glass gets cold. ”

“ In this way hydrogen gas is produced and escapes by the bent tube. When all the air has been expelled the gas should be ignited as it escapes, and a piece of cool porcelain held over the flame. If there be no deposit it is plain that neither the zinc nor the sulphuric acid, contains arsenic. A portion of the suspected fluid is next introduced into the flask by the funnel, and the issuing gas again tested. Should a stain giving the characters alluded to above be produced, the fluid contains arsenic in some form or other. ”

“ A mixture consisting of one part of manganese dioxide and four parts of potassium chlorate is placed in the flask A and gently heated. The oxygen is evolved and escapes through the tube B. It is collected by bringing over the end of the tube the mouth of a bottle completely filled with water and inverted in a vessel of water, as shown in the figure. The gas rises in the bottle and displaces the water. In the preparation of large quantities of oxygen, a copper retort (Fig. 5) is often substituted for the glass flask. ”

“ It is slightly soluble in water, but dissolves freely in alcohol, ether, and chloroform. When a one per cent. solution of it is treated with648 potash or soda it rapidly acquires a characteristic rose colour. Heated in a flask with a water-bath in contact with excess of ammonia, it gives upon evaporation of the liquor in the open air, a magnificent blue colour, very soluble in the water. This solution treated with acids, produces a very fine dichroic liquor, violet and transparent by transmission, and carmine red and turbid by refraction. ”

“ A large flask, provided with a bent glass tube for conveying the gas, and a tube-funnel for introducing the acid, is the most convenient form of apparatus. A tubulated retort may be used, but the generating flask or bottle is to be preferred.
Carbonic acid is rapidly evolved, and may be collected, with some loss, over water in the pneumatic trough. If required dry, the gas must be passed over fragments of fused chloride of calcium, placed in a large tube, or through a small quantity of concentrated sulphuric acid, and collected by displacement or over mercury. ”

“ A strong solution of potassium hydroxide together with several small bits of phosphorus are placed in the flask A, and a current of coal gas is passed into the flask through the tube B until [Pg 243] all the air has been displaced. ”

“ Use forceps to fold and transfer the filter to a 10-mL volumetric flask. Add 10.0 mL 99:1 benzene:methanol. Stopper and shake the flask vigorously for 1 min. Allow the flask to stand at least 2 h. Transfer the solution in the impinger to a separatory funnel. Wash the impinger with two 15-mL portions of 0.1 M NaOH, and add the washings to the separatory funnel. Add 0.05 M H2SO 4 until the pH is less than 7. Extract the Kepone with two 5-mL portions of benzene. Shake vigorously for 2 min and allow 5 min for the phases to separate. Combine the benzene layers in a 10-mL volumetric flask. ”

“ The flask is then well cooled with an ice-and-salt mixture, until the temperature of the acetone is between 0'0 and 5'0. Stirring is started, and 4160 cc. of commercial concentrated sulfuric acid is run in at such a rate that the temperature of the mixture never rises above about 10'0. This addition is accomplished in about five to ten hours. The stirring is continued for three to four hours longer, while the flask still remains immersed in the original freezing mixture to which no further amount of ice is added. ”

“ SAMPLE PREPARATION: 5. Transfer the sorbent from Tube A and Tube C to separate 50-mL volumetric flasks. Discard glass wool plugs and oxidizer (Tube B) . 6. Add absorbing solution to sample in 50-mL volumetric and bring to the mark. 7. Stopper flask and shake vigorously for 30 sec. Allow solids to settle. 8. Pipet 10 mL of extracted sample into a 50-mL volumetric flask. NOTE: Start reagent blanks at this step. 9. Add 1.0 mL hydrogen peroxide solution, 10.0 mL sulfanilamide solution, and 1.4 mL NEDA solution. Mix thoroughly after each addition. 10. Allow 10 min for complete color development. ”

“ Erlenmeyer's Flasks (Fig. 3) .—Erlenmeyer's flasks of 75, 100, and 250 c.c. capacity are extremely useful. For use as culture flasks care should be taken to select only such as have a narrow neck of about 2 cm. in length.
Kolle's Culture Flasks (Fig. 4) .—These thin, flat flasks (to contain agar or gelatine, which is allowed to solidify in a layer on one side) are extremely useful [Pg 5] on account of the large nutrient surface available for growth. A surface cultivation in one of these will yield as much growth as ten or twelve "oblique" tube cultures. ”

“ Having weighed the U-tube and got the apparatus in order, weigh up 1, 2, or 5 grams of the substance and place in the flask. Fill the pipette with dilute acid, close the clamp, and cork the flask. Then see that the apparatus is tight. Open the clamp [Pg 426] and allow from 10 to 20 c.c. of the acid to run on to the assay. Carbonic acid will be evolved and will be driven through the tubes. The gas should bubble through the sulphuric acid in a moderate and regular stream. When the effervescence slackens the clamp is opened and the greater part of the remaining acid run in. ”

“ When no more carbonic acid is evolved, another tube from this last flask is connected with the aspirator, the pinch-cock of the pipette open, and air drawn through the apparatus for about half a minute, and thus all the carbonic acid evolved absorbed, or the flasks may be slightly heated. ”

“ Failing in this way to separate the acids in the form of their esters, the mixture of esters and alcohol was examined qualitatively; 75 c.c. was taken and saponified with 80 c.c. N/1 NaOH in a distilling flask, with inverted condenser, for half an hour, until all the fragrant smell of the esters had disappeared. 71 c.c. N/1 HCl was then added, and the apparatus connected with a condenser in the usual way. ”