# Experiment 9: Determination Of Water Hardness Using A Titrator

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Glen Mings CHEMISTRY 1 SUMMER 1 Experiment 9 Report Submitted: June 28, 2015 Title: Determination of Water Hardness Using a Titrator Purpose: To find out how “hard” my tap water is; specifically the concentration of calcium carbonate in ppm, and compare it to the four classifications. Procedure: Using a titrator, I measured how much EDTA solution it took to bond all of the Ca2+ ions, which was determined when the EBT turned from purple to blue. And since the reaction is 1:1 stoichiometric, we can assume that the moles of EDTA used equal the moles of calcium ions. Data Collected: | Initial EDTA volume | Final EDTA volume | Total volume of EDTA used | Trial 1 | 7.0 ml | 6.6 ml | 0.4 ml | Trial 2 | 6.6 ml | 6.3 ml | 0.3 ml |…show more content…
Based on the analysis of your local water, would you classify its hardness as soft, moderate, hard, or very hard? Explain your answer. Answer: 33 ppm falls within the Soft Classification (0-60 ppm). B. Approximately how much calcium would you ingest by drinking eight 8-oz glasses of your local water? Hint: 1 oz (fluid ounce) = 29.57 ml. Answer: 8 oz x 29.57 ml/oz = 236.6 ml per 8-oz glass 236.6 ml is equal to 0.2366 L (in one 8-oz glass) 0.2366 L x 0.00033 mol/L = 0.00007808 moles of Calcium 0.00007808 moles x 40.078 molar mass of Ca = 0.003129 grams 0.003129 grams of Ca = 3.129 mg of Calcium per 8-oz