Solubility of Calcium Carbonate in ppm: 114. 80 ppm Solubility of Calcium Carbonate calculated using Ksp: 7. 05 ppm There is a big difference between two numbers because of two possible reasons: _ The filtration process possibly went not as accurate as It should. _ I heated the water while dissolving CaCO3, and that made it more soluble. _ The errors came from the titration, due to the fact that the color change of the solution is not easy to define. (Purple to blue) I might have put too much titrant into the solution, and that would cause a difference. 2.
water hardness is a water quality that demonstrates the quantity of minerals in certain water sample. The bigger the amount of minerals present, the harder that water will be. Minerals responsible for making water hard are primarily: Calcium and Magnesium. These minerals usually exist in form of salts in the ground, which are soluble in water/acid. Therefore, the salts react with water or rain (slightly acidic), the salt dissolve and the ions are now present in the water. It’s to say the minerals are carried to the water from the ground. PPM is parts per million. 3.
Water is the most important molecule that exists on the Earth. Without water living beings would not be able to live. Water is used for an immeasurable number of things. There are many properties of water, which makes this molecule so unique. One which people overlook is hardness. Hardness is defined in the Chemistry: The Central Science by Prentice Hall's as being "water that contains a ...
As in this lab, the endpoint should also be the equivalent point, so when we reached the endpoint, it means the titration is finished. 4. Highest water hardness: Sample in titration 3 – Dr. Layson’s Untreated Well Water (190. 94 ppm) Lowest Water Hardness: Sample in titration 5 – Dr. Layson’s Raw Well Water treated with a Brita Water Filter (33. 03ppm).
These observations make sense because of course after using the Filter, the hardness should be decreased. For example, the Angola tap water is softer than the untreated well water, but both of them are harder than the SOFTENED well water.
Ion exchange is to take out the cations that harden the water, and replace that with other ions such as Na+ and K+. This method is really effective because as the water goes through the bed of ion exchange materials, the hardening ions are removed, leaving the water soft and more satisfactory for usage. As we can see in the calculation, the hardness is reduced greatly by using the Filter. In titration 4 and 5, the amount of EDTA required to reach the endpoints is really little, due to the fact that the water samples are already softened in preparation, so the results do make sense. III. Conclusion:
This lab gave me a better understanding of water hardness and titrating method. Now I know how much concentration of minerals in water would it take to be called hard water, and how different –hardness wise, are all the water samples. The calculations and results are fairly good and reasonable, as already discussed above. There are several things that could have been improved for better results: _ An easier to be defined indicator. _ More accurate glassware. _Human errors/ perspectives: For example, each person has his/ her own opinion on which is a blue or purple color, so the results would be different among everybody.