1. What ppm values (and standard deviations) did you determine for each type of water?

Buxton hall’s water had 42 ppm of CaCO3 present in all three trials conducted. The standard deviation from this test was 0. Kroger water had a 46.2 ppm of CaCO3 in the first trial, 50 ppm in the second trial, and 43.2 ppm in the third trial. The standard deviation for the second water sample was 3.41. Crystal Geyser water had a 16.42 ppm of CaCO3 in the first trial, 21 ppm in the second trial, and 22 ppm in the third trial. The standard deviation for the third sample was 2.97.

2. According to the table provided in the Introduction section, what is the water hardness of each of your samples?

According to the table provided, 0-50 CaCO3 ppm is considered …show more content…
We then proceeded to create a control with 50 mL of DI water with 2 drops of eriochrome black T for comparison which turned a blue. Next, we added 50 mL of water from Buxton Hall into a volumetric flask and added 3 mL of pH 10 buffer. We then added 2 drops of eriochrome black T to the water and placed a stirring bar inside. We placed the flask on the stirring plate underneath the burette that contained EDTA. We turned the stirring plate onto a low setting that would aid in mixing the EDTA in with the water. From that point, we titrated 10 mL and the color of the water sample changed from pink to blue. This same test was conducted two more times with the same water sample. In each trial, we titrated 10 mL of EDTA and witnessed the water change color from pink to blue. Next, we performed three trials with Kroger water. We added 50 mL of the water into a volumetric flask along with 3 mL of pH 10 buffer, 2 drops of eriochrome black T, and a stirring bar for each trial. The first trial required 11 mL of EDTA to change color, the second trial required 12 mL of EDTA, and the third trial required 10.3 mL of EDTA. We then conducted three more trials with Crystal Geyser water following the same procedure used for the first and second water sample tests. In the first trial, 3.9 mL of EDTA was titrated to change …show more content…
We conducted three trials that each included 50 mL of water, 3 mL of pH buffer, and 2 drops of eriochrome black T. The first trial we filled the burette to 40 mL mark with EDTA and titrated until the EDTA was at the 50 mL mark. The first trial had a total of 10 mL of EDTA in it which allowed it to change from a pink color to the same hue of blue present in the control. Based off of calculations, there was 42 ppm of CaCO3 present in the first trial. When we conducted the second trial, we filled the burette to the 0 mL mark and titrated 10 mL. In the third trial, we started with 12 mL of EDTA and titrated 10 mL. All of the trials conducted took 10 mL of EDTA to promote the correct color change. Considering all trials required the titration of 10 mL, there were 42 ppm of CaCO3 present in all