Chem 112 Technical Abstract

2529 WordsApr 30, 201311 Pages
Determination of Cations and Anions through Elimination and Confirmation Tests By: Symantha Resendiz Introduction A topic of great importance to all scientists is the identification of compounds, which is relevant in all aspects of their work in some way shape or form. Weather it may be determining what is causing sickness or what is polluting the air, it is very prevalent in the science world. In project 2, identification of cations and anions was preformed through a series of confirmation and elimination tests that ultimately led to identifying an unknown ionic compound made of cations and anions. Materials and Methods Part 1- Cation Tests To begin, 5 centrifuge tubes were added 10 drops of one cation and labeled…show more content…
The mixture was then transferred to a clean centrifuge tube via pipet, carefully not wetting the upper walls of the tube. Zinc granules were then added and the tube was immediately plugged with cotton 1/3 of the way into the tube. The tube was then warmed in a hot water bath for about 5 minutes, the folded red litmus paper was inserted at the top of the tube with a wet crease. After a few minutes, nitrate is indicated on the wet crease of the litmus paper, turning it blue. For the Carbonate test, 25 mg of carbonate sample was added to a centrifuge tube and 3 drops of 6 M H2SO4 was added. A disposable pipet was used to transfer a drop of Ba(OH)2, that hung directly from the pipet over the carbonate solution, and the observations of the drop were recorded. Part 3-Cation and Anion Analysis For the cation analysis, 0.566 g of an unknown compound was dissolved completely in 5mL of distilled water in a centrifuge tube, thus confirming this solution as a stock solution. A flame test was performed on the stock solution to give a general idea of what test was to e preformed on the stock solution deriving the information from our logic trees in part 1. The logic tree from part 1 and the flame test confirmed that we needed to conduct an ammonia test on the stock solution. To being the ammonia test, 15 M NH4OH was added drop wise (about 20 drops) to the stock and the color of the solution and the color of the solution was recorded. 10 more drops of 15 M NH4OH
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