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 … Read more
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 … Read more
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 … Read more
https://www.youtube.com/watch?v=VUeooyhD5Xk The chemistry of cyanide solutions is complicated because the cyanide ion forms compounds and complexes with many elements. Some cyanide species are highly toxic whereas others are relatively inert and harmless. Molecular hydrogen cyanide (HCN) is the most toxic form of cyanide. Under most conditions, HCN exists as a gas which readily dissipates or reacts … Read more
FIG. 35 gives an idea of the spectroscope and of its different parts. P is a flint glass prism, having a refracting angle of 60° and resting on a brass plate fixed on a brass support, S. The brass plate carries the collimator tube C, in the end of which nearest to the prism is fixed … Read more
PREPARATION OF SOLUTION FOR BASES 1. Boil the finely-divided substance in distilled water. 2. If insoluble, add ¼ its bulk of strong HCl and boil for two or three minutes. 3. If still insoluble, treat a fresh portion with strong HCl and boil for five minutes ; then add an equal volume of water and warm. The … Read more
Note 1. Do not boil with Na2CO3 unless necessary. If only alkalies are present it is unnecessary. Note 2. If organic acids and Groups I. and II. or H2CrO4 are present add HCl, and pass H2S before boiling with Na2CO3 to make solution (4). The following should be tested for separately:— HNO3.—Black ring test, with … Read more
Take a few crystals of potassium chlorate (KClO3), place them in a clean dry test-tube, and heat them gently over a small bunsen flame; the salt begins to split, then fuses. Insert into the test-tube a splint of wood, glowing at the point, but do not allow the wood to quite touch the fused salt. The splint, which … Read more
Our Hydrogen Gas experiment involves taking one or two grams of zinc, put them in a test-tube, and add a few drops of dilute sulphuric acid; an effervescence takes place, and bubbles of gas rise through the liquid. Put a lighted taper into the test-tube ; a slight explosion takes place, and you see a momentary flash. … Read more