Re: Chem 2 Poster Project

[nadya musayev]

Unfurtunately, I cant figure out how to open up the whole poster, so that I can see it. Bellow, I filled in the blanks for the discussion. Also, maybe we can add a few more points (if they were not added yet) about what water hardness means for humans and for fish species as well.

Based on the tables shown in the results, there seems to be a direct positive correlation between hardness and conductivity. The average hardness of the pre, post and reference samples were found to be 200 (ppm), 400 (ppm) and zero (ppm) respectively. Their conductivity was averaged to be 2011(µS), 9067.5(µS) and 92 (µS), respectively. This indicates that hardness measures the amount of ions, such as calcium, magnesium, iron and zinc present in water and a higher conductivity indicates that there is a greater concentration of metals present in the samples.
These results can be understood based on the theories of electrical conductivity. The electrical conductivity of water measures the total amount of dissolved solids present in water. These solids mainly include calcium and magnesium, which are almost completely dissolved in the presence of water. When dissolved in water, these elements dissociate into positive and negative ions, making them excellent conductors of electricity. These minerals seep into the water from dirt, rocks, irrigation systems etc.

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It is believed that water hardness does not endanger human life. Infact, calcium or magnesium found in drinking water may be used as a supplement. Water hardness, however, may affect pipes by increasing residue build-up and thus decreasing the pressure of the water throughout a facility. Hard water also may require use of more soap or detergent during laundry. hard water may also leave residue on shower doors and tubs.
Different fish have different requirements for water hardness. Overall, however, fish function via osmoregulation, where osmosis takes place and minarals such as calcium, magnesium, potasium and zinc enter the fish organs to support factors such as heart and bone health.

souces:
http://www.cichlid-forum.com/articles/hardness.php
http://www.watersystemscouncil.org/VAiWebDocs/WSCDocs/1683274HARDNESS.PDF