Qualitative Analysis of Zinc Sulfate

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Report of the Qualitative Analysis of Zinc Sulfate Introduction The analytical chemistry skills of determining the components of an unknown sample can be life saving, as when cats and dogs mysteriously died from eating tainted pet food. By identifying the lethal substance (melamine) using a similar process as the one performed in this laboratory, the lives of many animals were saved. In order to determine what elements an unknown ionic compound is composed of, several tests have to be conducted. By testing the sample for its cation and anion separately, an accurate result can be achieved utilizing logic trees. This experiment can only be carried out if the solubility rules are understood and a flame test result chart is available. Materials and Methods Part 1 To commence this part of the experiment, five labeled test tubes were filled with 10 drops of their corresponding cation solutions, K+, Fe3+, Zn2+, Cu2+ and Co2+. The colors of the solutions were recorded. Next, the metal hydroxide elimination test was carried out. No more than 20 drops of 6M NaOH were added dropwise to each solution until a precipitate was observed. Changes in the solution were recorded. An additional 10 drops of 6M NaOH were added to the solutions that formed a precipitate to test for amphoteric species. For the ammonia test, 10 drops of each metal cation solution were added to corresponding labeled tubes. Then, no more than 20 drops of 15M NH4OH were added dropwise until colored complex or a precipitate was formed. An additional 10 drops of 15M NH4OH were added to the solution. To conduct the confirmation flame test, 20 drops of each metal solution were added to the corresponding labeled centrifuge tubes. After setting up the Bunsen burner and adjusting the flame, the Nichrome loop was dipped in concentrated HCl and then placed above the inner blue cone in the flame until no

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