Bottles

Beside all technical reasons the big advantage of a pneumatic test is, that the steam drums can remain within the line because first we have no additional load for the bearing and only small adjustments (for the connection with the pressurisation unit and the tightening of the man ways for the applied low temperature gas test) have to be done to make the drum ready for a pneumatic loading. The pressurised air is available in every paper mill and even if the maximum pressure does not fit, the use of a compressor or pressure bottles produce no problems. 

Interestingly, a general thermodynamic relationship allows the surface area of a porous system (without ink bottles) to be calculated from porosimetry data, note Section XVII-16B. The equation is [45]... 

Handschuh H, Gantefor G and Eberhardt W 1995 Vibrational spectroscopy of clusters using a magnetic bottle electron spectrometer Rev. Sci. Instnim. 66 3838... 

Iodine is a dark-coloured solid which has a glittering crystalline appearance. It is easily sublimed to form a bluish vapour in vacuo. but in air, the vapour is brownish-violet. Since it has a small vapour pressure at ordinary temperatures, iodine slowly sublimes if left in an open vessel for the same reason, iodine is best weighed in a stoppered bottle containing some potassium iodide solution, in which the iodine dissolves to form potassium tri-iodide. The vapour of iodine is composed of I2 molecules up to about 1000 K above this temperature, dissociation into iodine atoms becomes appreciable. 

Aqueous hydrogen fluoride is a weak acid (see above) and dissolves silica and silicates to form hexafluorosilicic acid hence glass is etched by the acid, which must be kept in polythene bottles. 

This reaction proceeds very slowly in absence of light, and aqueous solutions of potassium manganate(VII) are effectively stable for long periods if kept in dark bottles. 

All the silver halides are sensitive to light, decomposing eventually to silver. In sunlight, silver chloride turns first violet and finally black. The use of these compounds in photography depends on this (see below). (All silver salts are, in fact, photosensitive—the neck of a silver nitrate bottle is black owing to a deposit of silver.)... 

Storage of Specimens. Solid compounds after purification should be stored in bottles or in corked specimen tubes, according... 

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.

Pure Ether. Pure ether (entirely free in particular from water) is frequently required in the laboratory, and especially for the preparation and use of Grignard reagents. It is best prepared in quantity for classes by adding an ample quantity of granular calcium chloride to a Winchester bottle of technical ether, and allowing the mixture to stand for at least 24 hours, preferably with occasional shaking. The greater part of the water and... 

Assemble the apparatus shown in Fig. 56. F is a 200 ml. flat-bottomed flask supported on a sand-bath and connected by a glass delivery-tube to the wash-bottle B, which is about two-thirds full of 10% aqueous sodium hydroxide solution. A second delivery-tube leads from B into a beehive stand (or between two earthenware tiles placed side by side) in a pneumatic trough T containing water. 

The preparation of absolute ethanol in moderate quantity for classes may be carried out as follows. Pour 3 Winchester bottles (i.e., 7-8 litres) of rectified spirit into a 3-gallon (14-15 litre) can C (Fig. 58), add about 600 g. of the... 

The absolute ethanol obtained in this way should have d., o 794, It is very hygroscopic, and the bottle in which it is stored should preferably have a well fitting ground-glass stopper alternatively, the bottle can be closed with a tightly fitting rubber stopper but not with a cork, as corks contain appreciable quantities of water. 

For this preparation, it is particularly necessary that the sodium acetate should be free from traces of water. The anhydrous material can be prepared by gently heating the hydrated salt (CHsCOONa,3HjO) in an esaporating-basin over a small Bunsen flame. The salt dissolves in its water of ciystallisation and resolidifies as this water is driven off further heating then causes the anhydrous material to melt. Stir the molten anhydrous material to avoid charring, and then allow it to cool in a desiccator. Powder the cold material rapidly in a mortar, and bottle without delay. 

Add about 60 ml. of petroleum (b.p, 60-80°) with stirring to the fraction of b,p, 150-180°, thus precipitating the pure anhydrous pinacol (2 5-3 8 ) Filter this off, and then shake the filtrate with ca. 4 ml, of water the remaining pinacol now separates as the hexahydrate (5 g.). The two crops may be united and recrystallised from ca. 10 ml, of water (total yield of hexahydrate, 8-9 g,). Dry and bottle the product rapidly as described in (a). 

Aluminium isopropoxide can be obtained as a fine powder from technical sources. When the bottle has once been opened however, the stopper should be firmly replaced and covered with wax more conveniently, the stoppered bottle can be kept in an atmospheric desiccator over calcium chloride or sodium hydroxide, preferably in the dark. 

The crystalline sodium sulphide (NajS,9H20) used to prepare the disulphide is very deliquescent, and only a sample which has been kept in a well-stoppered bottle and therefore reasonably dry should be used. A sample from a badly-stoppered bottle may contain, in addition to the crystals, a certain amount of aqueous solution, in which hydrolysis and partial decomposition will have occurred such a sample should therefore be rejected. Add 4 2 g. of finely powdered sulphur to a solution of 16 g. of the crystalline sodium sulphide in 60 ml. of water, and boil the mixture gently for a few minutes until a clear solution of the disulphide is obtained. 

Picric acid if stored in bulk should, for safety, first be damped. Smaller quantities may be safely kept whilst dry, but should be stored in bottles having cork or rubber stoppers glass stoppers should never be used for potentially explosive substances, because on replacing the stopper some of the material may be ground between the neck of the flask and the stopper, and so caused to explode. 

Place about i g. of the base in a test-tube, and cover with concentrated (about 20%) sodium hydroxide solution. Bring the mixture gently to the boil, keeping the test-tube lightly closed with the finger meanwhile to prevent undue escape of vapour.. A.s the solution boils a strong fishy odour of dimethylamine is detected, and white fumes form when the test-tube is held near an open bottle of concentrated... 

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