Water Testing Laboratory

Today, the atoms, and the rest of our summer chemistry class conducted a series of tests in order to find certain ions in various water samples. Iron, Calcium, Chloride, and Sulfate were found in at least one sample. Through a confirming test method we were able to seek out the precipitate in each water sample and therefore find the presence of each ion. We used qualitative tests instead of quantitative tests to find the ions by looking at the presence or absence of a particular substance instead of the amount. One of the water samples was a reference solution that was known in order to see what the reaction should look like when the ion is present. Our lab was very successful and we were able to deduce very good information from the four tests we conducted.

Procedure
There are not too many steps to this lab; however, the key is the repetition and not getting lazy when repeating the same steps for each different ion. You prepare your 24-well by labeling it with tape and writing the different water samples so you do not get mixed up, ie. control, reference, distilled, tap, and natural. After labeling each well, pour 20 drops of each sample water into a separate well using a Berel pipet or just the top to the sample container. Next, put 3 drops of the reactant (which varies for each element) to watch the reaction. The wells that have cloudiness should once stirred with a glass stirrer to see if some precipitants come up. If the reaction causes precipitants then the water sample must contain the element being tested for. If you are unsure, look at the reference to see the type of reaction you should expect. The reference obviously has that atom you are looking for. Continue these steps until you have found Iron, Calcium, Chloride, and Sulfate.

Questions

1. A reference solution allowed us to see what the reaction should look like knowing that the element we were looking for was definitely there.
2. Qualitative tests can test for items that you know you are looking for and want to see. However, if you would like to measure the amount of something in a substance a qualitative test is pointless.
3. Although these tests can tell you if the ion is present, it cannot officially say it is not there.
4. Residue from the control or reference could defile the tap water or any of the other samples and change the results!