Setting Point Apparatus

Setting Point — 69° to 70°. Use the apparatus shown in Fig. The bottle A is of 1 liter capacity, such as a Kerr Mason Jar No 12, and the Pyrex test tube B (1.5 x 7 inch) is held in place by means of tape (a) around the top. A cork stopper (b) serves for holding Pytex test tube C, (1 x 6 inch). Cork stopper (c), inserted in tube C, has three holes, of... 

Some thermometers have standard taper joints or ridges on the body of the glass to fit specific equipment such as distillation or melting point apparatus. These thermometers provide two types of position control. They set the bulb at just the right height within specialized equipment and ensure that the liquid column is sufficiently immersed in the heated sample. However, most thermometers do not have built-in controls and the user must not only select the right thermometer, but also adjust the thermometer to its proper level within the equipment. 

A. There is no point in using a large Buchner funnel for a srnall amount of solid since you will collect a layer of solid one molecule thick and be unable to scrape it from the filter paper cleanly. If there is too much solid for the size of the funnel, you will have to repeat the filtration with a second set of apparatus or the solid may not suck dry quickly. 

ShulfbArs apparatus for determining the titer test of fatty adds consists of a tube 3 cm. diam. surrounded by a Dewar vacuum mantle, ffie outer diameter of which is 5 cm. and the he ht 10 cm. The molten paraffin is poured into the inner tube, which a closed by a cork fitted with an accurate thermometer. The vessel is slo y cooled widi shaking and the point at wluch without further shaking the thermometer remains steady and then rises is noted. The highest pdnt is taken as the setting point. 

Azobenzene can be obtained upon further reduction of the azoxy compound by adding a paste consisting of 16 parts iron and 40 parts 60 per cent caustic soda and heating at 110 120 C. The setting point of the reduction mass first sinks to a minimum of 25 C and then it rises to about 63 C. The apparatus may be stopped at that point and the azobenzene discharged. 

Automatic devices cause required acts to be performed at given points in an operation without human intervention. For instance, an automatic titrator records a titration curve or simply stops a titration at an endpoint by mechanical or electrical means (such as a relay) instead of manually. Automated devices, on the other hand, replace human manipulative effort by mechanical and instrumental devices regulated by feedback of information, so, the apparatus is self-monitoring or selfbalancing. An automated titrator may be intended to maintain a sample at some preselected (set point) state— for example, at pH = 8. To do this, the pH of the solution is sensed and compared to a set point of pH = 8, and acid or base is added continuously so as to keep the sample pH at the set point. This type of automated titrator is called a pH-stat [2]. 

The following is a thermally rather isolated copper container, controlled by resistance thermometers and restorative electrical heating approximately proportional to the square of temperature displacement from the set point. Manual reset is required for signilicant change of conditions. Resistance thermometry avoids the necessity for a precisely controlled reference temperature. The apparatus was constructed for investigation of piezoelectric frequency standards. It may be useful for other electronic elements, ... 

The chief disadvantage of the simple vacuum distillation set up shown in Fig. 11,19, 1 is that, if more than one fraction is to be collected, the whole process must be stopped in order to change the receiver B. It is of value, however, for the distillation of solids of low melting point the distillate can easily be removed from the receiver by melting and pouring out. For routine work, involving the collection of several fractious under reduced pressure, the most convenient receiver is the so-called Perkin triangle the complete apparatus for vacuum distillation is depicted in F g. 11,20, 1. The Claisen fla.sk A is fitted to a. short water... 

This last solution should be prepared slowly as it is quite exothermic. Set all three aside in a freezer. Now prepare the mixing apparatus which will be a stainless steel "mixing bowl" suspended In the ice/salt bath made earlier. We use a stainless steel bowl here so that heat transfer will be maximal, while preventing any corrosive interaction. A glass bowl will not be sufficient for larger scale preparations as it will not conduct heat fast enough to prevent the reactants from going over IOC (at which point the Haloamide will decompose and you ll have to start over). Take the Sodium Hydroxide solution out of the freezer once it is cool, but not cold. 

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