Essay on Water Hardness Titration

1052 Words Nov 11th, 2013 5 Pages
Title: Determination of Water Hardness Using a Titrator

Purpose: To become familiar with the concept of water hardness, practice a titration technique using a titrator, and determine the hardness of the local water supply.


1. Gather the test tube holder, small stopcock, 10-mL syringe (titrator), and 2 thick textbooks and the LabPaq box or 5-6 thick textbooks.
2. Remove the plunger from the titrator and place it back in your LabPaq box.
3. Attach the stopcock to the tip of the titrator by placing the larger, clear, plastic end of the stopcock into the tip of the titrator and then twisting the stopcock into place. The stopcock should fit tightly into the titrator, so that the liquid will not leak.
4. Stack the
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25. Determine the total volume of EDTA used by subtracting the final EDTA volume from the initial EDTA volume and record the volume in Data Table 1.
26. Leave the titrator assembly intact. You will need it for future titrations in this experiment.
27. Pour the contents of the beaker down the drain and flush the drain with water. Thoroughly wash the beaker with soap and water to remove all of the EDTA solution from the beaker. When the beaker is clean, rinse the beaker with distilled water and then thoroughly dry.
28. Place the clean and thoroughly dry beaker back in the titration set-up, under the titrator.
29. If necessary, add more EDTA solution to the titrator.
30. Repeat Steps #14 through Step #28 two additional times (Trial 2 and Trial 3), using water from the same source.

31. Average the results from the three trials and record in Data Table 1.

Data Table 1: EDTA Titration Volume Initial EDTA volume (mL) Final EDTA volume (mL) Total volume EDTA used (mL)
Trial 1 8.8 8.5 0.3
Trial 2 8.4 8.2 0.2
Trial 3 8.2 8.0 0.2
Average 0.23

32. Carefully pour any remaining EDTA solution down the drain and flush with water. Wash all equipment with soap and water and return to the LabPaq box.
33. Using the following equation, determine average the concentration (moles per liter) of Ca2+ ions present in your water. Record the concentration in

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