Plunger Jig & Accelerated Jig
In the discussion of my paper on “ Close Sizing Before Jigging,” Mr. Louis remarks: “ What we really need to know as the basis of any consistent theory (of jigging) is what occurs during each hundredth of a second.” It is clear that for the further study of the laws involved, a jig-tester is […]
Gravimetric Analysis Precipitation Reactions Examples
The conditions essential to accurate gravimetric analysis have been given. As a rule such estimations come under one of four classes: Direct Estimations These are the most usual and accurate methods of gravimetric analysis. The element sought is precipitated and weighed generally as a compound, definite in composition. Direct Estimation by Loss Here the element […]
Quantitative Chemistry Gravimetric Analysis: PRECIPITATE
WASHING THE PRECIPITATE: A precipitate may be washed directly on the filter, or it may be washed partly by decantation and partly on the filter. If by decantation, the precipitate is allowed to settle, and the supernatant liquid is poured on the filter. Wash water is added to the precipitate, and after settling, the decantation is […]
Muffle Furnace
The accuracy of the silver-assay depends in great measure upon a careful regulation of the heat of the muffle furnace during the process of cupellation. At the beginning of the operation, a relatively high temperature is required to ” open ” the lead buttons, that is, to clear off the black film of oxide that […]
Gravimetric Analysis: Substance into Solution
Material of Vessels for Solution The student must consider the effect of the solvent used on the vessel. In most cases the solvent used is an acid or mixture of acids, and for such solvents glass and porcelain are generally used. Platinum may be used, provided no chlorine or other attacking agent be present. (See […]
Gravimetric Analysis: Precipitation
After solution, certain minor operations may or may not be necessary, but as a rule the next essential operation is that of precipitation. In his qualitative work the student has already come across many cases of precipitation, and he will find that many of the methods there used are again applied for quantitative purposes. Silver, […]
Gravimetric Analysis: Precipitate Filtration
When precipitation is complete the precipitate must be separated from the solution. The means of bringing about this separation will be described under this head. Under the next head (Washing) the completeness of this separation will be considered. Filtering Medium In quantitative gravimetric analysis the two materials generally used are paper and asbestos, and the […]
Quantitative Analysis Chemistry: GRAVIMETRIC METHODS
In the course of work completed, the problem so far met with has been the determination of the various elements (or compounds) present in a substance. In an ore, for instance, there may be present silica, iron, copper, arsenic, and sulphur, and it is the province of qualitative analysis to determine the presence or absence […]
Analytical Balance
Analytical Balance Principle In this place it will be sufficient to describe the usual chemical balance, designed to carry in each pan a load up to 100 gms. This balance can be obtained at a reasonable figure, and sensitive to 1/10 of a milligram (0.0001 gm.). In the section on Assaying the student will find […]
Homemade DIY Laboratory Still
In the use of the apparatus purchased for the new chemical laboratories of the university, no piece has given us more satisfaction, or has been a greater success, than a new still which is the subject of this paper. In the designing of this still I had two definite objects in view ; one, the […]