Water Hardness Essay

733 Words 3 Pages
Introduction
The definition of water hardness, in its simplest form, can be explained as, “the amount of dissolved calcium and magnesium in water.” Water hardness can be attributed to groundwater systems naturally flowing through soil and rock. While doing so, divalent amounts of cations from mineral sources dissolve into the water supply (USGS).

Water hardness is not harmful to people’s health. In fact, these minerals can be beneficial, as humans need minerals to survive. However, water hardness begins to cause problems when it comes its constant use in the home and in appliances. For instance, when the water is heated, it forms solid deposits of calcium carbonate. This type of mineral build-up can decrease the lifespan and efficiency of
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Atomic Absorption is a technique that determines the metals that are dissolved in a given solution by looking at light absorbance. The amount of absorbance in a sample is proportional to the concentration of the metal atoms in a sample. While testing is occurring, an aspirator is placed into the sample of water. A voltage is sent across the electrodes and excites either Mg or Ca inside the lamp of the spectrometer. When these excited atoms relax, monochromatic light is produced and passed through the water sample. While passing through the sample, some of the atoms will absorb this light. Different spectrometers will be used for each of the metals being tested. This is due to the fact the monochromatic light has a unique energy level for the various metals. The spectrometer will relay the absorbance value, which can be converted to determine the concentration of divalent cations in a sample (PSU …show more content…
EDTA titration tests the amount of divalent cations in a givens solution. In this titration, a known volume of a natural water sample is taken and the pH is adjusted to 10 by the use of an NH3/NH4 buffer. An EBT indicator is added to the solution, which should appear blue. If present in the solution Mg2+ will react turning the solution to a wine color. Thus why the start of the titration begins with the red color. EDTA solution is next added. EDTA reacts with Ca2+ forming a colorless chelate. As soon as enough EDTA has been added to chelate all of the Ca2+, the EDTA will react with the magnesium indicator, to turn the solution back to its original blue color. The end point of the titration corresponds to the amount of drops added, to where the solution definitively changes from the wine to the blue color (PSU

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