Determination of Water Hardness
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Texas A&M University *
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Course
1411
Subject
Chemistry
Date
Apr 3, 2024
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Pages
2
Uploaded by UltraMorning901
Determination of Water Hardness
Purpose:
Define soft and hard water in order to determine how CaCO3 affects water
hardness and how to measure it.
Procedure:
I was able to measure the water hardness by performing an EDTA/EBT
titration on a local water supply. The concentration of Ca2+ ions in the local water
supply sample was then estimated.
Data table 1: EDTA Titration Volume
Initial EDTA
Volume (mL)
Final EDTA
Volume (mL)
Total volume of
EDTA use (mL)
Trial 1
10 mL
7.5mL
2.5mL
Trial 2
11 mL
6.5mL
4.5mL
Trial 3
13mL
10mL
3mL
Average Volume
of EDTA Used
(mL):3.33m
Data Table 2: Water Hardness
Average Volume of EDTA
used (mL)
Concentration of CA2+
ions per liter of water
(mol/L)
Water Hardness (ppm
CaCO3)
3.33mL
0.00333 mol/L
333.2 ppm
Observation:
I observed that each water had a different volume. Different waters were soft and hard
Questions:
A. Because our calculations came out to 333.2ppm for the water hardness I would
classify the water as very hard. Anything above 180 ppm is very hard water.
B. 8oz x 8 oz =64 oz x 29.57mL= 1892mL=1.9Lx333.2mg/L=632.7mg
C. 1Lx333mg/L=333mgCa/1150mgCa=.289 x 100=28.9%
Conclusion:
can now recognize the difference between soft and hard water and
understand that the minerals in a water supply determine whether it is hard or soft. I'm
also more acquainted with titrator and EDTA/EBT solutions.
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