Michelle Chai
Block 6
Water Quality Thesis
How does one know if a liquid is safe to drink? In some places around the world that I’ve been to, I notice children drinking water that is foggy looking. If you see water that’s foggy, I don’t think you’d drink it either. In the labs we did, we tested to see which substances was the unknown, and we also tested for pH levels. These labs can help test whether the liquid is safe to drink.
In the Revisiting Zinc/Iodine Lab, we took 2 grams of zinc and 2 grams of iodine and mixed them together in 10 mL of water in a flask. We weighed the contents of the flask then swirled the flask. During the process of swirling, the temperature changes as well as the color of the water. After minutes of swirling, the flask became clear with zinc left over at the bottom of the flask. We then weighed the leftover zinc and found that it had lost mass. From this, we can tell that even though the liquid is clear, but there still may be something in it.
In the precipitation challenge, we were given an unknown liquid which contains two of the 8 known solutions. We had to determine which 2 solutions were combined to make the unknown. In this lab, we used a well plate and put a drop or two of two different known substances and mixed it together in a well. We tested for a reaction by mixing two known substances. Overall, we found 4 liquids that could be a possibility of one of the substances in the unknown.
On Day 2 of the lab, we took the 4 possible liquids and combined each liquid in a well with another drop of one of the other possible known substances. We tested for a

reaction but the substances were still clear. We then took a drop of the unknown in 4 wells and added a drop each of the 4 substances into the unknown wells. In the wells that included the unknown with a drop of the known substances, we saw a reaction in 2 of the wells with the combination of the known and unknown. We then took the two known liquids that did not react with the unknown and mixed them into our last well. We found that it did not make a reaction, but to test that it did not make another reaction, we added a drop of the unknown and it did not cause a reaction. From this, we can use