Discussion E3

Discussion E3 - After perfecting our testing method with a...

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Robert Collins Experiment 3 Josh Kurzman November 1, 2007 Discussion The analysis of water by means of physical and chemical change conceptualized the fact that the chemical composition of a liquid is not an observation that can be made by simply looking at it. Also, it emphasized the power of water as an aqueous solution. The purpose of analysis via changing the solution physically was to test for solutes in the solution, specifically salt in water in this experiment. By evaporating the water with a bunson burner, we were able to isolate any solute that was in the water. In the experiment, we were able to get a white solid that clung to the edges of the beaker after evaporating the water. It had a mass of 2.12g and through our calculations we found our initial sample of water to contain 3.25X10 -5 ppm. Next, we used chemical means of testing to determine exactly what elements formed the white solid in the first part of our experiment.
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Unformatted text preview: After perfecting our testing method with a known solution, we tested water samples from the same source as before for several elements. Although we did not find any nitrates present, we observed reactions when testing for Cl-and SO 4 2-. When testing for lead, we might have ‘over-reacted’ the solution and dissolved the precipitate. Our tests generated conclusive evidence of sulfates and chlorine in our samples of water. The lab was useful for the reason that I drink water daily, unaware of any solute in what I am drinking. Admittedly, I drink more carbonated substances than water, but I was glad to be informed of what is going into my body. The most obvious error we experienced was when we were testing for lead. Our results were that it didn’t exist but I suspect that we may have added too much reactant to the water. In the physical change, I see no sources of substantial error....
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This note was uploaded on 04/08/2008 for the course CHEM Chem 1A taught by Professor Van koppen during the Winter '08 term at UCSB.

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