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The Purpose of This Lab Is to Determine Whether a Liquid Is Hard Water or Not

Autor:   •  November 6, 2011  •  Lab Report  •  980 Words (4 Pages)  •  1,879 Views

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Lab Report: Hard Water


The purpose of this lab is to determine whether a liquid is hard water or not.


Hard water is the water that has a high amount of mineral in it, usually Ca2+ and Mg+. These cations enter the source of water by leaching from minerals within a wet underground layer of water- bearing rock, or an aquifer. According to the WHO, hard water is not harmful to human's health but it's a serious problem in the water industry. Household plumbing and appliances are also greatly affected by hard water conditions. Some of the effects include clogged pipes, water heater inefficiency and hard scaling. Hard water is also linked to decreased water flow or water pressure and seized (frozen) valves in faucets, water heaters, and fixtures. However, some researches prove that drinking too much hard water caused heart diseases in men or eczema in children. As the result, WHO set a standardize amount of how much calcium and magnesium can exist in drinking water to prevent damages.

Analyzing skill and an experiment are needed to test whether a liquid is hard water or not. First, add a buffer solution to keep the solution basic. Next, put a small amount of Eriochrom Black T so that the color of the water would change based on the amount of Ca2+ ¬ or Mg+. Observe the change of color. Then, a solution named EDTA should be added to determine how much Ca2+ there is in the water. Add EDTA until the water turns blue. Then use analyzing skill to figure out whether the water is hard or soft.


All Type Plumbing Company. "All Types Plumbing - Water Softener." All Types Plumbing - Plumbing, Heating Tooele, UT Salt Lake City, UT. Web. 03 Oct. 2011. <>.

Wikimedia Foundation, Inc. "Hard Water." Wikipedia, the Free Encyclopedia. Wikimedia Foundation, Inc. Web. 03 Oct. 2011. <>.

Laurison, Arlene; Fendall, Bob. "Chemistry Workbook", page 52-53.


If the amount of input EDTA increases in order to make the well water turns blue, then it's harder than the tap water from Elk Grove


Laurison, Arlene; Fendall, Bob. "Chemistry Workbook", page 52-53.

Data Table:

Tap water from Elk Grove Well water from Wilton

# of drops EDTA 1st time 16 28

# of drops EDTA 2nd time 16 29

# of drops EDTA 3rd time



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