Determination of Water Hardness Using a Titrator
From seeing all of my results and conclusion I now see that I didn’t understand this lab very well and that its not easy when others try to help. Since I have hard water it tells me that my water flows over and through rocks and minerals, like limestone.
The purpose of this lab is to become familiar with the concept of water hardness. We learn that hard water contains high levels of dissolved minerals that are in the form of metallic ions. Most of Ohio which is the state I live in either has moderately hard water or hard water. For as my town the city is moderate and the country is hard.
1) Put safety things on
2) Place the stopcock in the closed position on the end of the titrator and fill with 10 mL of EDTA solution. 3) Put a crumpled up paper towel under the titrator and allow a few drops of the solution to fall into the towel. This way it fills the tip of the titrator then close and throw the towel away. Then place the 100 mL beaker under the setup. 4) Use the graduated cylinder to measure exactly 10 mL of tap water from your sink. 5) Pour the tap water into the beaker then add 5 drops of pH 10 buffer solution. Swirl carefully the mixture in the beaker. 6) Read the volume of EDTA in the titrator and record the initial volume. Then slowly open the stopcock and add 1 drop at a time while swirling the mixture. 7) Once the solution turns a pale blue-gray color turn the stopcock off then record the final volume in the titrator. 8) Repeat steps 4-7 and fill in Table 1.
9) Pour the rest of the contents down the drain
Data Table 1: EDTA titration volume
| Initial EDTA Volume (mL)
| Final EDTA Volume (mL)
| Total Volume of EDTA Used (mL)
| Trial 1
| 9 mL
| 7.4 mL
| 1.6 mL
| 8 mL
| 6.6 mL
| 1.4 mL
| 5.2 mL
| 1.8 mL
Average Volume of EDTA Used...
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