Discussion and Scientific Explanations In this experiment, we were given three main goals to accomplish. We were to identify the compound through a series of organized experiments and analyze as many physical chemical properties as possible. During this experiment, we carefully examined the unknown compound and followed specific tests and steps to determine the identity of the compound. Our first week of testing, we began our experiment by observing the unknown compounds physical properties, which included state and color. The compound was clear/white with a granulated texture and crystallized state. There was no scent, as seen in Table 1. The second test we performed was the solubility test. Our group followed the directions of …show more content…
The fourth test we performed was the chloride anion test. To perform this test, we followed the directions in the lab manual to determine if our unknown compound would form a precipitate in a chloride substance. As seen in Table 5, it was found that our unknown compound did in fact form a precipitate when placed in the presence of chloride. This occurred because we placed our unknown compound in 1 mL of water, added 1 mL of HNO3 and 1 mL of AgNO3. This mixture formed a precipitate of AgCl (silver chloride) because the ions the two compounds are both ionic, therefore creating an ionic bond between the Ag and Cl. Due to the opposite bonds, the mixture creates a precipitate of AgCl, confirming our compound to consist of chloride. The fifth test we performed was the flame test, which is another way to identify cations in a substance. We used the nichrome wire to gather our sample and placed it over the Bunsen burner. We saw that the fire was a bright orange/yellowish color. We then tested the first substance on our list: Sodium and its burning color matched our unknown substance – bright orange/yellow. We then held up a blue cobalt glass to see if there was a change in color. When the unknown compound and NaCl both had blue flames and the yellowish orange was removed, we could determine that they were the same compound. We consulted our lab assistant to determine if our
The white color implies that chlorine is within the mineral oil, thus did not react. Since chlorine did not react, it means that bromide isn’t a possible anion, leaving chlorine as the anion. In procedure 5, the unknown compound produced water on the watch glass indicating it could be a hydrate. The hydrate test was inconclusive because the number of waters of hydration shown in Table 5 was half way between being lithium chloride monohydrate and lithium chloride 2. The percent error, shown in Table 5, between the expected percent of water in lithium monohydrate and the accepted value, was high at 40% which meant that the unknown could not be properly identified as a hydrate. Repeating the hydrate test produced a similar percent which is shown in Table 7. The reason for these high percent errors is because lithium chloride and lithium monohydrate are both hygroscopic. In addition, Table 6 shows an increase in mass when unknown #42 was left outside, which suggest that the unknown compound is
In this Chemistry Lab the main objective is to perform accurate chemical analysis for the quantity of elements and compounds in a sample. There will be a compound made then synthesized. The methods used were acid-base titrations, redox titrations, gravity filtration, and distillation. General conclusions included
The flame test had a variety of results. Most of the known compounds did not match our unknown except for Ca(NO3)2. Both Ca(NO3)2 and the unknown compound had a deep red/orange color flame. While Ca(NO3)2 had the closest results two other compounds had slightly different results but not different enough to rule them out. Those other two compounds were CaCl2 with a yellow/ orange color and CaCO3 with a reddish color.
Similarly, the sugar, baking soda, Epsom salt, and washing soda are all dissolved in water. Next, we observed the color after adding the universal indicator. The unknown substance came out a greenish yellow and almost perfectly matched, the Urocit-K had the same. Then, we tested the reactions the solids had with heat. The unknown substance did not react.
The compound was tested for the presence of ammonium, carbonate, sulfate, chloride, and nitrate, as seen in Table 2. The nitrate test produced a precipitate, indicating the presence of the nitrate ion in the compound. At this point it was hypothesized that our unknown compound was calcium nitrate.
Procedure: In this experiment, various chemicals were mixed together, to determine a reaction. Using two drops from chemical 1 and two drops of chemical two, unless otherwise stated, then recording the type of physical reaction or color changes that occurred.
The goal of the experiment was to identify Unknown 33A and 33B. Unknown 33A was a white, crystalline solid that had a sweet cherry smell and Unknown 33B was a beige, yellowish color liquid that was translucent and had a viscosity similar to water. Also, the liquid was homogenous and smelled sour, similar to mildew.
3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.
The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.
Our objective for the Sherlock Holmes Experiment was to illustrate that some chemicals can be identified or differentiated by simple chemical tests, such as solubility, pH, or color tests. In our group we had to test come common powders such as Alka-Seltzer, baking soda, flour, Vitamin C (ascorbic acid), and salt. Other chemicals that were used to do this experiment were vinegar, and Iodine 2 Solution. The equipment used to do this experiment was red litmus paper, and 5 test tubes per group.
The purpose of this particular lab was to experiment and identify the chemical and physical changes throughout the experiment.
The cations in both the known and unknown samples were identified by using qualitative analysis, of which were determined to be acidic, basic, or neutral by using litmus paper. Acid-base reactions, oxidation-reduction reactions, and the formation of complex ions are often used in a systematic way for either separating ions or for determining the presence of specific ions. When white precipitate formed after adding hydroxide, aluminum ion was determined to be present in the solution. However, nickel was determined to test positive when the solution changed to a hot pink color after adding a few drops of dimethylglyoxime reagent and iron was present when the solution was a reddish brown color when sodium hydroxide was added to the mixture at the very beginning of the experiment. Qualitative analysis determines that ions will undergo specific chemical reactions with certain reagents to yield observable products to detect the presence of specific ions in an aqueous solution where precipitation reactions play a major role. The qualitative analysis of ions in a mixture must add reagents that exploit the more general properties of ions to separate major groups of ions, separate major groups into subgroups with reactions that will distinguish less general properties, and add reagents that will specifically confirm the presence of individual
The objective of this lab was to use qualitative and quantitative measurements and observations to properly identify, and then confirm the identity of an unknown compound. After identification, the compound would have to be synthesized, in our case, through an acid-base reaction, followed by confirming its identity with the original unknown compound.
The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1.
Step 1 and 2 was repeated by using distilled water by replacing the test solution.