General laboratory apparatus

In the following sections, a brief account of general laboratory apparatus relevant to quantitative analysis will be given. The commonest materials of construction of such apparatus are glass, porcelain, fused silica, and various plastics the merits and disadvantages of these are considered below. 

The tubing glass is suitable for general laboratory use and chemical apparatus construction, though neutral or hard borosilicate are preferred for more severe conditions, these representing the most resistant glasses available in bulk form. 

The industrial experimenter, on the other hand, often cannot obtain complete control of all his variables, for frequently the scale of the experiment b so vast that an army of supervisors would be required to keep them under control. The attainment of good control may also be a difficult technical matter thus it in generally easy in a well-equipped laboratory to control temperatures within very fine limits with the usual thermostatic equipment. For a plant scale experiment this is generally quite impracticable.. Again, it is easy enough to provide excellent lagging for any laboratory apparatus to hg an absorption column 50 feet high, on the other hand, may be absurdly expensive. 

Variations in ki and with the respective phase stirring rates are determined first. Determination of as a function of liquid-side stirrer speed is carried out by physical absorption, absorption with slow chemical reaction, or absorption with an instantaneous chemical reaction of a pure gas for a well-known geometric interfacial area (generally the cross-sectional area of the stirred cell minus that of the blade-type stirrer). To determine ka as a function of gas-side stirrer speed Nq, absorption with instantaneous chemical reaction of a dilute solute is carried out. These values of L and k are specific to the geometry of the laboratory apparatus and to the solute gas. For other gases, k under the same conditions can be estimated by assuming it to vary as the square root of the diffusivity Dq of the solute gas. In the same way, for other liquids under the same conditions may be assumed to vary as the square root of the diffusivity of the dissolved gas. 

In investigating the action of carbon as a catalyst, Ipatiew employed a form of graphite mixed with clay which was in general use at the time for the manufacture of crucibles and other forms of laboratory apparatus. This substance, heated in a glass tube at 500° to 600° C., catalyzed the decomposition of alcohol almost completely according to the equation ... 

The use of dry heat as a method of disinfection has been largely confined to the sterilization of laboratory apparatus. It is used when steam heat would in some way damage the material being sterilized. Hot-air ovens are used in dry heat sterilization. The temperature most generally employed is 180° C. It is found that by slowly raising the temperature much glassware which would break if submitted to steam, can be satisfactorily sterilized. 

Previously, decaborane(14) was synthesized by pyrolysis of hazardous di-borane(6) in elaborate apparatus which precluded the use of the method for general laboratory work.1 The procedure given here is performed in standard glassware employing relatively safe materials and thus makes decaborane(14) generally available for the first time. 

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