Identification and Recreation of Unknown White Compound #643p November 13, 2012
The identity of the unknown solid white compound is determined and verified through a series of tests which uncover physical and chemical properties necessary for identification. A new sample of the same compound is then created to further prove the accuracy of the identification. The compound must be identified in order to be used. For example, KCl is used in medicine, scientific applications, and food processing. It also tastes a lot like sodium chloride, and is the main ingredient in dietary salt substitutes.1 The other possible compounds substance 634p could be have very different properties and uses though they look similar. Almost all of the possible compounds have practical uses and are used by chemists and industries, but in order to be used, the identity of this compound must be determined. Because many compounds have the same physical properties, chemical properties must also be tested to prove the identification. Potassium chloride has been studied extensively by chemists and much is known about it. It is a useful component of liquid fertilizers, an effective salt substitute, and treatment for hypokalemia among other things.1 This report will provide the repeatable methods- including measurements- used to identify and recreate unknown compound 643p as well as a discussion of measurement and procedure limitations and possible further experimentation. This sample of compound 643p can now be used to create a dietary salt substitute.
MATERIALS AND METHODS:
Materials. Chemicals used for precipitation tests include AgNO3, NaCO3, and BaCl2. Chemicals used for comparison include CaCO3, CaCl2, Ca(NO3)2, MgCl2, MgSO4, KCl, KNO3, K2SO4, NaC2H3O2, Na2CO3, NaCl, Na2SO4, NH4Cl, (NH4)2SO4, and K2CO3. Distilled H2O was used to dissolve compounds for testing. KOH and HCl were used for synthesis of the compound. Measuring tools and other devices are referenced below. Solubility. Five grams of the unknown solid white compound 643p were attained. To determine a basic physical property of the compound, a solubility test was performed in a test tube by mixing a 0.1g sample (massed on weigh paper on a scale) of the compound with a 1 mL of distilled water (measured and poured from 10 mL graduated cylinder). Reactivity. To determine some chemical properties of the compound, precipitate tests were performed. Aqueous solutions of the compound, each made with 1 mL distilled water and 0.1 g 643p, were mixed in test tubes with aqueous solutions of AgNO3(1 mL of 0.1 M), NaCO3(1 g in 1 mL H2O) and BaCl2 (1mL of 0.2 M)to determine the reactivity of the compound 643p with each compound. These tests were also performed on solutions of possible compounds that the 643p could be, in the same way, to determine which possible compound reacted and did not react with the compounds 643p did and did not react with respectively. Flame Color. Next, flame tests were conducted with a solution of 0.1 g 643p in l mL distilled H2O and samples of the remaining possible compounds with the same concentration. A wire loop was cleaned and dipped into the solution and held over the hottest part of the flame of a Bunsen burner. This procedure was completed for the each solution, cleaning the wire loop between each test to avoid contamination and recording and photographing each flame color and brightness. Verification. The tests above provide identification of the 643p as KCl. To verify this identification, a precipitate test with AgNO3 (1mL of 0.1 M solution) was done with both a known sample of KCl (0.1 g in 1 mL DI water) and a sample of the 643p (0.1 g in 1 mL DI water) side by side for easy comparison. These tests were done in test tubes. A conductivity test was also performed on both a solution of KCl and a solution of 643p (both 0.5 g in 20 mL DI water) using a laptop and conductivity probe. We were careful to make the concentrations precise...
References: 1 "The Nutrition Source." Harvard School of Public Health. N.p., n.d. Web. 05 Nov. 2012.
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