Laboratory apparatus

BENCH-SCALE APPARATUS. Laboratory combustion devices include flame-plate, pot-burner, and Institute of Petroleum Technology (IPT) wick-lamp apparatus. Small-scale combustors could be considered laboratory equipment, but results obtained... 

Apparatus(Laboratory) for Continuous Prepa-rations(lneluding Nitrations) of Explosives... 

Wear a self-contained breathing apparatus, laboratory coat, eye protection, and nitrile rubber gloves (and rubber boots or overshoes if spillage is large). Cover the spilled liquid with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop the mixture into a plastic container and, in the fume hood, add to a pail of cold water. Neutralize the mixture with 5% hydrochloric acid, let stand overnight, and then pour the liquid into the drain. Dispose of any solid with normal refuse. Wash the area of the spill with plenty of water.5-7... 

Repeatability and reproducibility should also be estimated. lUPAC gold book defines repeatability as the closeness of agreement between independent results obtained with the same method on identical test material, under the same conditions (operator, apparatus, laboratory and after short intervals of time), and reproducibility as the closeness of agreement under different conditions (operators. 

Random errors can be revealed by repeating the analysis under the same conditions or by comparing analyses made at different times under different circumstances (i.e. technicians, apparatus, laboratories). 

Apparatus Laboratory burner in accordance with ISO 10093 Laboratory burner in accordance with D 5025-94. 

Apparatus Laboratory burner in accordance with ISO 10093. Barrel length is 100 10 mm and inside diameter 9.5 0.3 mm. Bunsen Tirrill type humer of tube length 95 6 mm and inside diameter 9.5 (+1.6 mm, -0.0 mm). 

Alundum is used for highly refractory bricks (m.p. 2000-2100 C), crucibles, ref ractory cement and muffles also for small laboratory apparatus used at high temperatures (combustion tubes, pyrometer tubes, etc.). 

Measuring the gross heating value (mass) is done in the laboratory using the ASTM D 240 procedure by combustion of the fuel sample under an oxygen atmosphere, in a bomb calorimeter surrounded by water. The thermal effects are calculated from the rise in temperature of the surrounding medium and the thermal characteristics of the apparatus. 

In the presence of catalyst, usually platinum, ammonia is oxidised by oxygen (and air) to nitrogen oxide. NO. This reaction, used to obtain nitric acid from ammonia (p. 238), can be demonstrated in the laboratory using the apparatus shown in Figure 9.4 the oxygen rate should be slow. 

Pure water for use in the laboratory can be obtained from tap water (hard or soft) by distillation if water of great purity is required, distillation must be carried out in special apparatus, usually made of quartz, not glass or metal precautions must be taken to avoid any spray getting into the distillate. Water which is sufficiently pure for most laboratory purposes can, however, be obtained by passing tap water through cation-exchangers and anion-exchangers as described above, when the water is deionised . 

The more accurate apparatus shown in Fig. i(c) is strongly recommended when laboratory conditions enable students to retain their own apparatus over a complete course of work. A glass tube T, bent as shown, is fixed by the rubber-bands RB to the thermometer G. The... 

In most laboratories, drying ovens maintained at about 50° are available for the final drying of glass apparatus of all kinds. 

The use of more complex or more costly articles of equipment, such as catalytic hydrogenation apparatus, autoclaves, polari-meters, ultraviolet absorption spectrometers, etc., has not been described, because the type of such apparatus employed indifferent laboratories varies considerably, and students must be taught the use of their own laboratory equipment. 

It will be useful at the very outset to introduce the student to the apparatus that is commonly employed in the organic laboratory. Whether he will personally handle aU the types of apparatus to be described will, of course, depend (i) upon the duration of the course in practical organic chemistry and (ii) upon the facilities provided by the laboratory. Nevertheless, it is deemed advantageous that the student should, at least, know of their existence. 

All glassware should be scrupulously clean and, for most purposes, dry before being employed in preparative work in the laboratory. It is well to develop the habit of cleaning all glass apparatus immediately after use the nature of the dirt will, in general, be known at the time, and, furthermore, the cleaning process becomes more difficult if the dirty apparatus is allowed to stand for any considerable period, particularly if volatile solvents have evaporated in the meantime. 

The only disadvantage is that the procedure does not give accurate results if the compound sublimes the capillary tube method should be used in such cases, and it may be necessary to employ a sealed capillary tube. This apparatus should find a place in every laboratory. It is... 

Ether. The most satisfactory method for the removal of (diethyl) ether is either on a steam bath fed from an external steam supply or by means of an electrically-heated, constant-level water bath (Fig. 77, 5, 1). If neither of these is available, a water bath containing hot water may be used. The hot water should be brought from another part of the laboratory under no circumstances should there be a free flame under the water bath. It caimot be too strongly emphasised that no flame whatsoever may be present in the vicinity of the distillation apparatus a flame 10 feet away may ignite diethyl ether if a continuous bench top lies between the flame and the still and a gentle draught happens to be blowing in the direction of the flame. 

The high-pressure water supply service is employed for the operation of the ordinary filter pump, which finds so many applications in the laboratory. A typical all metal filter pump is illustrated in Fig. 11, 21, 1. It is an advantage to have a non-return valve fitted in the side arm to prevent sucking back if the water is turned off or if the water pressure is suddenly reduced. Theoretically, an efficient filter pump should reduce the pressure in a system to a value equal to the vapour pressure of the water at the temperature of the water of the supply mains. In practice this pressure is rarely attained (it is usually 4 10 mm. higher) because of the leakage of air into the apparatus and the higher temperature of the laboratory. The vapour pressures of water at 5°, 10°, 15°, 20° and 25° are respectively 6-5, 9-2,12-8, 17 5 and 23 8 mm. respectively. It is evident that the vacuum obtained with a water pump will vary considerably with the temperature of the water and therefore with the season of the year in any case a really good vacuum cannot be produced by a filter pump. 

Ethylene. Under the influence of pressure and a catalyst, ethylene yields a white, tough but flexible waxy sohd, known as Polythene. Polyethylene possesses excellent electric insulation properties and high water resistance it has a low specific gravity and a low softening point (about 110°). The chemical inertness oi Polythene has found application in the manufacture of many items of apparatus for the laboratory. It is a useful lubricant for ground glass connexions, particularly at relatively high temperatures. 

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