Determination of Hardness of Water

2. To titrate a hydrochloric acid solution of “known” concentration with standardized 0.5M sodium hydroxide.

8 test tubes were then labelled A-H, 1ml of DCPIP was added to each of the test tubes. 2ml of NaHCO3 was added tubes A through G.

The purpose of this experiment was to determine the percent by mass in a hydrated salt, as well as to learn to handle laboratory apparatus without touching it. The hydrated salt, calcium carbonate, was heated with high temperature to release water molecules. Gravimetric analysis was used in this experiment to determine the percent by mass of water in a hydrated salt. The hypothesis of this experiment was accepted on the basis that the percent by mass of volatile water in the hydrated salt would be fewer than 30%. The percent by mass was determined by the mass of water loss devised by the mass of hydrated salt multiplied by total capacity

Having a hard water with Ca2+ and Mg2+ ions at home could be an annoying thing for many people. When hard water is heated the minerals in it precipitate out including the Ca+ and Mg+2 ions, these mineral start to form a coat on shower doors, bath tops, soap scums which result of addition of soap to hard water and people will find difficulty cleans with soap since hard water lose some affections in dissolving soaps as soaps get mixing with ions and less soap will be dissolving. As a response of this hard water problems water softener came to the market. Water softener works by exchange the hard water ions Ca2+ and Mg2+ with slats such as Na+ and k+ this way the hard water ions will be reduced or eliminated leading to better water quality [2].

In the Chemistry of Natural Waters Lab we were to collect a sample of water, ranging from a fountain, stream, bottle, or tap water. After we collected the samples we all did many tests to see what the hardness was for each one. Water hardness is determined by the amount of Calcium and Magnesium in the water.(2) Water that has more Calcium or Magnesium is considered to be harder than water with less of those two elements. When you use soap and detergent, this is where you see water hardness coming into play in everyday life when you are washing things.

The first question in the problem read: In caring for a patient after delivery, you are to give 0.2 mg Ergotrate Maleate. The ampule is labeled 1/300 grain/ml. How much would you draw and give? (60 mg = 1 grain). In reading this problem, the information that I need is given: I need to draw and give 0.2 mg of a certain medication. Also given is that 60 mg is equal to 1 grain. Another important piece of information is that there is 1/300 grain per 1 ml of solution, without this information, the problem would be unsolvable. The process that I

In this experiment, the precision of percent by mass of sodium carbonate was decent. It seemed to be consistent, although we seemed to have an outlier in our fifth trial. I believe this was due to human error of adding too much vinegar to this graduated cylinder. The accuracy of our results was decent in comparison to the rest of the class’s data, but our results were on the higher end compared to the averages of the class data, though not too high to be considered

But the result met the expectation because the color of the solution was reached the end point by changing from red to blue. The primary errors may occur because of misreading the buret while measuring the volume of EDTA. Another error can affect the result of the experiment was that letting the volume of EDTA excess the ending point; so that the volume of EDTA was overapply that lead error. The last source of error was that our unknown sample had high percentage in mass of Mg2+, so that we need more than 50 ml of EDTA( which was the capability of the buret) to reach the end point. We had to refill the buret while measuring; and also the large volume of solution made the color harder to recognize the end point. That also led to error.

Throughout the course of the experiment, the weight of the beaker and liquid, the weight of the Alka-Seltzer tablet, the weight of the beaker with liquid plus the weight of the tablet, and the weight of the beaker with all of the contents after the bubbling ceased remained roughly constant and did not vary widely. However, a trend is able to be seen in Figure 1. It is clear that as the mL of vinegar used in each experiment run increased, the mass percent of NaHCO3 increased as well. During the construction of Figure 1, experiment runs four and six were deleted to create the expected graph which consists of a gradual increase and eventually leveling off into a plateau.

The Results from ETDA (table 7) show that tap water Mifflin Hall (400 ppm) is hardest than the four other water samples. It is followed by tap water Harleysville (340 ppm), well Water Wyckoff (320 ppm), Stream Water Raleigh (110 ppm) and Tap water Yosemite (80 ppm). This order supports my hypothesis. Tap water Yosemite is relatively soft compared to the other water samples. I have predicted my sample to be the hardness and tap water Yosemite to be the softest. Also, these results support my hypothesis in the assumption that they show that stream water Raleigh is moderately hard as expected. Nevertheless, I expected tap water Yosemite to be relatively soft but the data show that it is moderately hard. In fact, I assumed that tap water Yosemite would be slightly hard because in California ground water is stored in alluvium. They are made up of loose gravel, sands, and silts and they contain a very low concentration of divalent cations. Maybe the fact that rocks vary from the state of California due to the difference in geology might

This showed that there was a limiting reactant in the Alka-Seltzer tablet that forced the production of product to end. When the volume of vinegar reached 10 mL, the average mass of NaHCO3 plateaued equating to an average of 45% by mass of NaHCO3. Due to the high amount of trials, the accuracy in the determination of percent by mass of NaHCO3 increased. However, the standard deviation showed that the precision was low. This brings The percent by mass of NaHCO3 in each tablet in this experiment increased as the amount of vinegar used in solution increased.

The retained solution from the NaHCO3 extraction was used to precipitate the P-toulic acid. Drop wise 3M HCl was added to the extracted solution carefully until no more precipitate was formed and the solution tested acidic, with a pH reading less than 3 as indicated by pH paper testing. A piece of clean filter paper was then weighed and the mass recorded in a lab notebook. A vacuum filtration system was constructed with a Buchner funnel

In this experiment, a saturated calcium sulfate was already made and ready to use. 25.00 mL of this solution was then mixed with 10 mL of an ammonia buffer and 1 drop of

The purpose of this lab is to determine whether a liquid is hard water or not.

For this experiment, a pH meter was used so this part of the experiment began with the calibration of the pH meter with specified buffers. The buret was then filled with the standard HCl solution and a set-up for titration was prepared. 200g of the carbonate-bicarbonate solid sample was weighed and dissolved in 100 mL of distilled water. The sample solution was then transferred into a 250-ml volumetric flask and was diluted to the 250-mL mark. The flask was inverted several times for uniform mixing. A 50-mL aliquot of the sample solution was measured and placed unto a beaker. 3 drops of the phenolphthalein indicator was added to the solution in the beaker. The electrode of the pH meter was then immersed in the beaker and the solution containing the carbonate-bicarbonate mixture was titrated with the standard HCl solution to the phenolphthalein endpoint. Readings of the pH were taken at an interval of 0.5 mL addition of the titrant. After the first endpoint is obtained, 3 drops of the methyl orange was added to the same solution and was titrated with the standard acid until the formation of an orange-colored solution. Readings of the pH were also taken at 0.5 mL addition of the titrant.