Determining The Soluble Ion In Part III

To determine which ions are present in the two unknown solutions. This will be accomplished by mixing three known solutions with three testing solutions. You will use this information to determine which ions are present in the unknown solutions.

The Copper Chloride displayed and used to complete this lab had led us to the following observations;

to the unknown solution in order to completely precipitate the cations in part A. 2 A compound

In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor

When the red Co(NO3)2*6H2O crystal was added to the white NH4 crystal, and water was added to dissolve, the solution turned blue in color. As the solution was nixed, the color changed to that of a blue-purple and a blue precipitate formed. When the 6 M NH3 began to be added, the color shifted to dark purple color after 15 mL of ammonia and the amount of the precipitate was less. After 20 mL of ammonia, the solution became a red brown with very little of the blue precipitate. After 30 mL of ammonia, the solution was similar in color to an iodine solution, a dark brown-red, almost black in color. At this point there was no visible precipitate on the surface of the solution. After 40 mL of the ammonia had been added, the solution was the same iodine like color as before. When closely examined, there was a black precipitate that had settled on the bottom of the beaker. At this point, hydrogen peroxide, 3% H2O2, was added to solution. After 4 mL of the H2O2 was added, the solution was the same color and the precipitate had not changes. After 8 mL of the H2O2, there was not noticeable change. After 12 mL of the H2O2, the solution was slightly redder in color but the precipitate had not changed. After 15 mL of H2O2, the solution was the same color and no changes had occurred to the precipitate. At 17 mL, the solution began to effervesce slightly, though there

Wash your hands and all of the equipment with mild soap and water. As a final rinse on the equipment, use deionized water. Dry all equipment thoroughly.

1. Gather appropriate lab equipment and secure a safe workspace with open ventilation, away from children and pets. All chemicals will be combined in the 96 well plate. Don’t contaminate end of pipet with other chemicals.

The materials needed for this experiment included test tubes, a test tube holder, the unknown compound #202, 35mL beakers, gloves, safety goggles, ethanol (to clean equipment), stirrer (to mix solutions), the 15 possible compounds that are provided, pH strips, distilled water, wooden splints, spatula to get out unknown compound #202, waste bucket, Bunsen burner, graduated cylinder, 500mL beaker for the waste, plastic dishes to measure out compound and the scale.

HCl (Hydrochloric acid) Procedure: Take a chemplate and put one or two pieces of zinc, copper and magnesium as shown in the figure. Then add 5 to 10 drops of given solutions into each well. Observe the reactions for 10 minutes and record. Data/Observations: Reaction 1 Zn + CuSO4 → ZnSo4 + Cu Hypothesis: There is going to be a reaction because zinc is more active than copper

we didn't expect. Step by step, we were able to determined what the reactant was. According to our observations, we can conclude the

We then let the solutions sit awhile before recording our observations. In wells A2, A3, A4, B2, B3, C2, C3, D2, and D3, precipitates formed. Also, in well B1 had a color change but no precipitate.

The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1.

To begin the experiment and start the process of narrowing down the list of twenty-five compounds, a Tollens’ test was performed on the chosen unknown (Unknown #6). In a test tube, 1 mL of 0.3 M AgNO3 was added along with 0.5 mL of 3 M NaOH. To that, 2 M NH4OH was added dropwise until the brown silver oxide precipitate dissolved. After, one drop of the unknown was introduced to the mixture, the tube was shaken and left to sit at room temperature for ten minutes. The predicted silver mirror coloration did not appear indicating a negative test result.

The cations in both the known and unknown samples were identified by using qualitative analysis, of which were determined to be acidic, basic, or neutral by using litmus paper. Acid-base reactions, oxidation-reduction reactions, and the formation of complex ions are often used in a systematic way for either separating ions or for determining the presence of specific ions. When white precipitate formed after adding hydroxide, aluminum ion was determined to be present in the solution. However, nickel was determined to test positive when the solution changed to a hot pink color after adding a few drops of dimethylglyoxime reagent and iron was present when the solution was a reddish brown color when sodium hydroxide was added to the mixture at the very beginning of the experiment. Qualitative analysis determines that ions will undergo specific chemical reactions with certain reagents to yield observable products to detect the presence of specific ions in an aqueous solution where precipitation reactions play a major role. The qualitative analysis of ions in a mixture must add reagents that exploit the more general properties of ions to separate major groups of ions, separate major groups into subgroups with reactions that will distinguish less general properties, and add reagents that will specifically confirm the presence of individual

Two samples of unknown #8 were taken and weighed at 0.4004g (Sample 1) and 0.3985g (Sample 2). The two samples were placed into separate 400 mL beakers along with 200 mL of DI water containing 4 mL of 6M HCl. Two samples of the BaCl2.2H2O weighing 1.51g each were placed into separate 250 mL beakers and dissolved using 100 mL of DI water. 95 mL of each of the BaCl2.2H2O solutions were added to the earlier mentioned 400 mL beakers containing the unknown #8 solutions, leaving roughly 5 mL to later test completeness of precipitation of the sulfate ion. The newly added mixtures were heated for 3 minutes and then were allowed to cool and settle for 10 minutes. The remaining 5 mL of BaCl2.2H2O solution was added to their respective unknown solutions to ensure precipitation completeness of sulfate ions. Upon completeness, the two solutions were heated for 90 minutes at near boiling temperatures. After the 90 minutes, the solutions were removed from the heat, cooled, covered with parafilm and stored until the following week.