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Hard water analysis, and lab report...

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Hard Water Analysis

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Hard Water Analysis in San Antonio Priscilla Rangel CHEM-1412-008

Hard Water Analysis

2 Abstract

San Antonio is notoriously known for its extremely high levels of hard water. This is due to the large amount of minerals, and contaminants dissolved into the tap water that is used throughout the city. Although water hardness is not extremely harmful to people, it does have a vast amount of negative effects. The level of hardness in water can be measured by titration with an EDTA solution, which will change the color of the water solution depending on the amount of metal ions present. Through the collection of data on several hard water analysis trials the average level of hardness of water in San Antonio was estimated to be 257-343 ppm.

Hard Water Analysis

3 Introduction

There are many instances in everyday life that apply the analytical chemistry method of testing for water hardness, such as swimming pools, and any type of water system both public and private. Water hardness is defined as the measure of dissolved minerals, most commonly being calcium and magnesium, in water. Hard water has an exceptionally high content of dissolved minerals. A few common examples of water hardness in day-to-day life can be seen in the water that comes from the sink or shower, and can be recognized as a cloudy, white coat. This is due to hard water leaving high amounts of mineral deposits behind after the water evaporates. Hard water is not beneficial because it causes deposits that will reduce the effectiveness of the water flow through pipes. Other problems can occur such as a washing machine wearing out clothes or damaging equipment that uses water from pipelines. Hard water also has physically negative effects on humans. The minerals in hard water can change the pH balance in human skin, which leaves the barrier against harmful bacteria and infections vulnerable. Which is why it is very important to test the hardness, mineral concentration, of water and soften it if necessary. This can be tested through the use of an acid base titration, which measures the concentration of minerals in water using gpg, and ppm.

Hard Water Analysis

4 Research

An acid-base titration is a method of quantitative chemical analysis that involves dropping a titrant of a standard concentration, and volume through a burette into an analyte solution that has an unknown concentration. The two solutions must be acidic and basic. In this experiment, a metallochromic indicator was used in the analyte, which is used to identify the metal ions in a solution, in this case calcium and magnesium in the water sample. The indicator binds to the metal ions and makes a reddish-pink color which indicates an acidic substance with a pH lower than 7. However, if the pH is higher than 7, the indicator turns blue, which means there are no metal ions bound to it. This is where the metal chelator, Ethylenediaminetetraacetic acid (EDTA), becomes useful. EDTA has a chemical compound that allows there to be a stronger bond with metal ions. When it is applied to the titration, the titrant EDTA is dripped into the analyte water solution that contains the indicator. The EDTA will bind with the metal ions and pull them away from the indicator. Once all of the metal ions are bonded to the EDTA, the indicator will have no ions to bind to, resulting in a change of color from reddish-pink to blue. The immediate color change allows the volume of EDTA to bind with all of the metal ions. The volume that is consumed by the EDTA can be used to calculate the amount of metal ions present in the analyte. The measurement of water hardness is most commonly calculated using parts per million (ppm). Ppm is a weight to weight ratio, where one ppm of calcium is synonymous with one gram of calcium in one million grams of water. When the volume of EDTA consumed, the ppm of calcium can be calculated by some conversions of units and the final result can be compared with

Hard Water Analysis

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the water hardness chart below, with ‘soft’ containing low amounts of calcium and ‘very hard’ containing high amounts of calcium.

Hard Water in San Antonio The average amount of water hardness in Texas is over 200 ppm, which ranks Texas as the state with the sixth highest hardest water levels in the United States (). Cities all over Texas have all struggled with hard water, and San Antonio is notoriously known for its mineral concentrated water with certain zip codes having a water hardness level that is more than 350 ppm (). One of the primary reasons for the water hardness levels in San Antonio is the build up of rock formations is bodies of water being mixed into aquifers when rain falls (). These rock formations are dissolved into the water, which contain minerals that are then recycled into the San Antonio Water System. Although there is no way to fix the water hardness level from its direct source, the San Antonio Water System, there are a few solutions that can soften water in San Antonio households. One of the most popular solutions is the use of a water filtration system. A water filtration system removes contaminants from water through a filter that is connected to a water

Hard Water Analysis

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line. The system traps sediments, and then activated carbon acts like a magnet to remove other compounds that cannot be filtered out as easily. There have been issues with older filtration systems exchanging minerals like magnesium and calcium for salts and sodium, which are just as if not more harmful than regular minerals that are dissolved in water. This has evoked a series of new age filtration systems that ensure that no new contaminants are added to the water once it has been filtered. However, before any solutions can be put into action it’s important to test the level of hardness in water first through a series of experiments.

Data Collection Hard Water Levels in San Antonio Zip Codes

PPM

78230

357.32

78242

355.76

78249

245.85

78257

254.87

78261

232.68

77064

306.46

78251

348.92

Hard Water Analysis

7 Conclusion/Discussion

The level of hardness in San Antonio has become a serious problem, and will have a series of long term effects on the citizens living there. The average amount of ppm in water is between 257 and 343, which means that it is very hard and contains an excessive amount of minerals. In order to fix this there needs to be water softeners that are effective, and do not replace these minerals with sodium. Another way this issue can be solved is by obtaining water from a source that has less sediment, and rocks to avoid minerals dissolving into the water in the first place. The data collected speaks for itself, and there are a multitude of ways to fix the water hardness levels in San Antonio.

Hard Water Analysis

8 References

Hardness of Water, www.usgs.gov/special-topic/water-science-school/science/hardness-water?qt-science_cen ter_objects=0#qt-science_center_objects. “Texas.” Water Hardness in Texas and City Hard Water Information | HydroFLOW USA , www.hydroflow-usa.com/texas-water-hardness. “Water Quality FAQs.” San Antonio Water System , 8 Aug. 2019, www.saws.org/your-water/water-quality/saws-water-quality-concerns/faqs/. Water Quality Report . 6 July 2020, www.saws.org/your-water/water-quality/water-quality-report/.

“Water Softeners San Antonio, Texas: Chambliss Plumbing Company.” Chambliss Plumbing San Antonio, 28 Sept. 2020, chamblissplumbing.com/water-softeners/#:~:text=The%20water%20hardness%20in%20 San,without%20a%20water%20softener.?adlt=strict....