Flask sizes

Flask clamps are made to fit a wide range of sizes of flask. These are devices for holding flasks while the necks are being worked and enable the whole flask to be rotated easily. They usually consist of a handle with three or four sprung prongs which hold the body of the flask. Some clamps are made so that they can be adjusted to fit a range of flask sizes. 

For the analysis of ribosome loading in the cytosol or ER by velocity sedimentation, it is necessary to utilize a minimum of 1 to 2 X 107 cells. The techniques described here are optimized for a 75 cm2 culture flask and may be altered to accommodate other cell culture flask sizes. For time... 

The flask size will depend on the volume of eluate to be concentrated. 

The procedure for conducting the hydrogenation of 0.5 mol of a compound is described below. (Flask sizes and reagent quantities suitable for the hydrogenation of other molar amounts of substrate are listed in Table 2.6.)... 

Your delivery system is likely to be a steam pot (also called a steam bath) (see Fig. 6.3). Steam pots may be made out of copper, brass, or cast aluminum. One of the benefits of using steam for heating is that the steam bath is designed to accommodate a wide variety of flask sizes all that is necessary is to select a nested lid that is just smaller than the size of your flask. The lid should be selected before the steam valve is opened. Otherwise the container will become too hot to handle safely, and further setup will become more difficult and dangerous. If you need to change a nested lid after it has been heated, be sure to use tweezers or tongs. 

Kjeldahl digestion flask heaters, with flask supports (100 ml flask size). 

Electric heating Bmi ray electric bunsens suitable (minimum loading 375 watts) or Kjeldahl digestion flask heaters with flask supports (100 ml flask size). 

Experimental Determination of Boiling-point. Unless only minute quantities of the liquid are available cj. p. 60), the boiling-point is usually determined by simple distillation. For this purpose, the apparatus shown in Fig. 2 is assembled. A distillation flask A of suitable size is fitted to a water-condenser B, the water supply of which is arranged as show-n. An adaptor C is sometimes fitted in turn to the condenser, so that the distillate... 

Round-bottomed flasks (Fig. 22(A)) of various sizes and having necksof various lengths and widths. They can be closed with stoppers (Fig. 22(B)), or fitted with any of the following units reflux air-condensers (Fig. 22(C)) or water condensers (Fig. 22(D)) distillation heads, of the simple knee-tube type (Fig. 22(E)), or with a vertical joint (Fig. 22(F)) for thermometers, etc., or with... 

Fig. 23(E) shows a distillation assembly particularly useful for distilling ether from an ethereal extract. When all the ether has distilled over, the drop-ping-funnel may be replaced by a thermometer for distillation of the residual liquid the adaptor A and the receiver B can then be replaced by the simple adaptor shown in Fig. 23(D) and a flask or bottle of suitable size.

General Considerations. With liquids and solutions the most serious losses are due to (a) transference from spherical flasks and difficulties of drainage, (b) retention by filter-papers, (c) absorption by large corks. As containers for small quantities of liquids it is therefore often convenient to use pear-shaped flasks A and conical test-tubes or centrifuge-tubes B (Fig. 29). (In this and subsequent figures, approximate dimensions are given to indicate a convenient size.)... 

Flat-bottomed flask (the so-called Florence flask) with vial mouth. The sizes vary between 50 ml. and 40 litres. 

The size of the flask to be employed depends upon the quantity and nature of the liquid to be distilled it should be one half or at most two-thirds full. If too large a flask is used, superheating and, sometimes, decomposition may occur. 

Fig. II, 16, 1 illustrates a set-up for simple fractionation a Hempel column is shown, but it may be substituted by a modified Hempel, a Vigreux or an all-glass Dufiton column. The Hempel column may be filled with glass rings, h porcelain Lessing rings, or with porcelain rings. The mixture to be fractionated is placed in a bolt - head flask of convenient size (it should be one third to one half full), a few fragments of porous porcelain added, the column fixed in position, and a water condenserattacfied to the side arm. The distillate is collected in small flasks or in test tubes. The bulb of the thermometer should be just below the level of the side arm.

The technique of the filtration of hot solutions has already been described in Section 11,28. The filtration of cold solutions will now be considered this operation is usually carried out when it is desired to separate a crystalline solid from the mother liquor in which it is suspended. When substantial quantities of a solid are to be handled, a Buchner funnel of convenient size is employed. The ordinary Buchner fimnel (Fig. 11,1, 7, a) consists of a cylindrical porcelain funnel carrying a fixed, flat, perforated porcelain plate. It is fitted by means of a rubber stopper or a good cork into the neck of a thick-walled filtering flask (also termed filter flask, Buchner flask or suction flask) (Fig. 11,1, 7, c), which is connected by means of thick-walled rubber tubing (rubber pressure tubing) to a similar flask or safety bottle, and the latter is attached by rubber pressure tubing to a filter pump the safety bottle or trap is essential since a sudden fall in water pressure may result in the water sucking back. The use of suction renders rapid filtration possihle... 

The set-up of Fig. 11, 41, 3 ensures the complete condensation of the steam when a rapid flow of steam is necessary for satisfactory results, and is useful in the distillation of large volumes of liquids of low vapour pressure, such as nitrobenzene. Thus the flask A containing the mixture may be of 3-litre capacity and B may be a 1-litre flask the latter is cooled by a stream of water, which is collected in a funnel and conducted to the sink. The receiver C must be of proportionate size all stoppers... 

Attention is directed to the fact that ether is highly inflammable and also extremely volatile (b.p. 35°), and great care should be taken that there is no naked flame in the vicinity of the liquid (see Section 11,14). Under no circumstances should ether be distilled over a bare flame, but always from a steam bath or an electrically-heated water bath (Fig.//, 5,1), and with a highly efficient double surface condenser. In the author s laboratory a special lead-covered bench is set aside for distillations with ether and other inflammable solvents. The author s ether still consists of an electrically-heated water bath (Fig. 11, 5, 1), fitted with the usual concentric copper rings two 10-inch double surface condensers (Davies type) are suitably supported on stands with heavy iron bases, and a bent adaptor is fitted to the second condenser furthermost from the water bath. The flask containing the ethereal solution is supported on the water bath, a short fractionating column or a simple bent still head is fitted into the neck of the flask, and the stUl head is connected to the condensers by a cork the recovered ether is collected in a vessel of appropriate size. 

Flasks. Round-bottomed, flat-bottomed, conical (Erlenmeyer) and bolt-head flasks up to a capacity of 2-3 litres are generally fitted with a 524 socket f those from 5 to 100 ml. are available with a 514 or 519 (from 25 ml.) socket. Round- and flat-bottomed flasks exceeding 1 litre in capacity are supplied with 534 necks. Whilst all sizes of sockets can be obtained from the manufacturers, it is usually convenient to limit the socket sizes to a small number (say, 514, 519, 524 and 534), thus per mitting interchangeability with the minimum number of adapters. 

Reduction adapters. These may be employed to connect condensers, still-heads, etc. to flasks, extraction apparatus and the like. Numerous combinations (Fig. II, 56, 2) are, of course, possible, but the commonest sizes are socket 514 to cone 519 or 524 socket 519 to cone 524, 529... 

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