water testing lab

Livia and Adam

Abstract:

The purpose of the water testing lab was to find the presence of an ion in different solutions. In order to complete this procedure, we placed different test solutions, including distilled water, reference solution, control water, tap water, and ocean water, into the wells of a chemplate. Then, for the test of the Calcium ion, we added drops of sodium carbonate into each of the wells, to test whether the ion was present or not. If it was, the solution often turned into a milkier consistency, instead of a clear solution. For the test of the Iron Ion, we placed two drops of potassium thiocynate into the well. In the Chloride Ion test, we placed drops of silver nitrate into the well, and lastly, in the Sulfate Ion test, we added drops of barium chloride to the well. As we completed each of these tests, we discovered the presence of certain ions within these solutions.

Procedure:

Starting with the Calcium Ion test, we placed 20 drops of solution into 5 of the wells on the chemplate. Next, we added four drops of sodium carbonate to each of the 5 wells. Then we recorded our observations. The reference solution, which was calcium chloride, turned out to be the only solution in which the ion was completely present.

  

Then we rinsed out our chemplate and began the Iron (III) Ion test. We started the procedure by adding 20 drops of solution into a well of the chemplate. Then we added two drops of potassium thiocyanate test reagent to each of the wells. The reference, which was the Ferric Nitrate, solution turned out to be the only solution in which the ion was completely present.

  

After rinsing out our chemplate after the Iron test, we started the Chloride Ion test by adding 20 drops of solution into the chemplate. Then we added three drops of silver nitrate test reagent to each of the wells. After recording our observations, we found that the reference solution, calcium chloride, was somewhat milky, but still slightly clear. We also found that the tap water solution became unclear within a few minutes, and the ocean water was extremely unclear and contained the ion.

  

Then we rinsed our chemplate out are started the Sulfate Ion test. We added 20 drops of solution into the chemplate, and then added three drops of barium chloride test reagent into each of the wells. After recording our observations, we found that the reference solution, ferrous sulfate, had a yellowish composition, the control solution was slightly milky and more dense towards the center, and the ocean solution was whiteish and slightly milky.

CALCIUM

Solution	Observations	Result
Distilled	Remained clear	Ion is not present
Reference (Calcium Chloride)	Milky solution, somewhat unclear	Ion is present
Unknown/Control	Remained the same, slightly more foggy	Ion is slightly present
Tap water	Remained clear	Ion is not present
Ocean	Remained clear	Ion is not present

IRON

Solution	Observations	Result
Distilled	Remained clear	Ion is not present
Reference (Ferric Nitrate)	Dark, reddish solution, looks almost like red wine	Ion is present
Unknown/Control	Remained clear	Ion is not present
Tap water	Remained clear	Ion is not present
Ocean	Remained clear	Ion is not present

CHLORIDE

Solution	Observations	Result
Distilled	Remained clear	Ion not present
Reference (Calcium Chloride)	Milky consistency, however still clear	Ion somewhat present
Unknown/Control	Remained clear	Ion not present
Tap water	Became slightly unclear and milky after waiting a few minutes	Ion slightly present
Ocean	Very unclear and milky	Ion present

SULFATE

Solution	Observations	Result
Distilled	Remained the same	Ion is not present
Reference (Ferrous Sulfate)	Yellowish, slightly milky	Ion is present
Unknown/Control	Whiteish, slightly milky and more dense	Ion is present
Tap water	Remained clear	Ion not present
Ocean	Whiteish, slightly milky, cloudy	Ion is present

Lab Questions:


1. A reference solution was a solution of known composition that was used as a comparison, in which contained the sought ion, and the water blank was known not to contain any ions of interest.

2. Qualitative tests identify the presence or absence of a substance in a sample, but the test does not determine the specific amount of a substance in a sample, which is important in certain tests.

3. These tests cannot absolutely confirm the absence of an ion because sometimes the amount of a substance is so little that it cannot be detected.

4. Our observations may have altered if we had not cleaned our chemplate between the tests, because of the possibility of certain chemicals from each solution contaminating the remaining tests.