Using Confirmation and Elimination Tests to Find Cations and Anions

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Using Confirmation and Elimination Tests to find Cations and Anions Project 2, 111-521 Jessica Vargas *, Brittany Donald, Callie Cheatham Introduction: It’s important to understand how to identify compounds and which ones have negative effects towards humans and animals. Through the use of elimination and confirmation tests, certain anions and cations can be removed from consideration when attempting to discover the identity of a compound. This can be applied to the real world when trying to understand what drugs and ingredients cause negative effects on the health of humans and animals. A common knowledge of solubility rules, recognition of amphoteric metal hydroxides and element color when flame tests are performed, and the reason for the formation of precipitates are needed to understand the results of the experiment. With this knowledge at hand, it is possible to identify and unknown compound through qualitative analysis. Materials and Methods: Part 1 Cation Tests: To begin the experiment, 6M NaOH was added to centrifuge tubes containing potassium, iron (III), zinc (II), copper (II), and cobalt (II) in the metal hydroxide test. Drops were added until a precipitate was observed and separating the cations into two groups, those that did and those that didn’t form precipitates, eliminating certain cations. Additional drops of NaOH were then added to test for any amphoteric cations. For those that tested negative, 15 M NH4OH was added in the ammonium hydroxide test to observe for the precipitate color which further separated the cations. The final step was the flame tests which confirmed the cations’ identity. After a Bunsen burner was setup, a Nichrome loop was dipped in HCl and placed above the flame until no color was observed in order to more accurately observe the color of the cation when placed in the flame. Each cation was added into centrifuge

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