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Experiment 10: Naturals Waters Formal ReportChem 113 Section 002Mercy UrenaName of Partners:Rachel Weis, Amy Vasquez, Julia WebsterOctober 23, 2020
1IntroductionWater hardness is a measurement used to assess the amount of dissolved polyvalentcations in a particular water sample. The presence of these cations, primarilyand,aC2+gM2+tends to occur when water comes into contact with natural minerals such as limestone, dolomite,or gypsum¹. Water that contains a large amount of these polyvalent cations amongst variousothers are said to be hard or harder in contrast to water with a combined low amount.Today, the importance of water hardness can be seen in how it affects manufacturers andindustrial corporations. When hard water is heated, solid deposits can form². Should this occurinside equipment like industrial boilers for example, it can lead to a serious reduction in life ofthe equipment as well as interferences with heat transfer. This can oftentimes lower theefficiency of said product and be very costly to fix³. Due to this, companies utilizing water mustbe very conscious of its hardness and actively try to manage it.This is typically done through various methods of hardness analysis. Hard water can betreated by boiling the water, utilizing an ion exchange process or precipitating the cations asinsoluble salts. Boiling the water is not the greatest method when dealing with large quantities,so it isn’t very efficient. Ion exchange is a very useful technique whereandareaC2+gM2+exchanged for sodium ions that do not form solid precipitates and therefore can not causescaling⁴. Precipitation of these ions is also very useful. There are a variety of chemicaltreatments, for example, the addition of lime, that are effective in precipitating the ions asinsoluble salts which can then be removed through filtration or settling¹.In this experiment, we utilized EDTA as a complexing agent forandalongaC2+gM2+with proper indicators, EBT, that allowed us to have a thorough analysis of the hardness of oursamples. My group chose not to collect samples from natural sources, instead opting to pick
2commercial brands. The four brands we chose to sample are Fiji, Aquafina, Perrier and PolandSpring. These were all bottled samples commercially sold around the world and advertised asoriginating from natural sources. My sample in particular, Poland Spring, seemed to originatefrom a groundwater or spring source. This particular source can suffer from a highermeasurement of calcium and magnesium ions because it is likely the water will flow past andreact with natural minerals³. The main goal of this project was to determine the water hardness inour samples to be able to compare them to one another. I expected all of our samples to berelatively soft, with only small amounts of dissolved polyvalent cations because they are bottledsamples and are legally required to meet certain guidelines⁵. I hypothesized that my sample