Faith Tuma
Mr. Tuckey
13/05/14
Honours Chemistry 11
Sleuth Your Slurry
Abstract:
This labaratory report shows that when presented with an unknown chemical substance, identification of that substance is revealed through a seires of tests that involve chemical and physical properties of that substance.
Problem:
You are given an unknown chemical substance that you need to be able to identify. How are you going to do this? The compound can be either harmful or toxic, so what you need to do is test all of its physical and chemical properties, and then find out the synthesis of the substance. Qualitative testing and quantitative testing is essential in discovering what the unknown is.
…show more content…
6. Since I mixed my unknown with and it formed a percipitate, I am able to conclude it is insoluble. I compared the results with other anions from my table of solubilities, and phosphate’s results are the only ones that matched with mine, but sulfate’s did not. This helped me to figure out the known anion.
Cation Percipitate Test #3
1. For this percipiate test with my unknown H chemical, I mixed it with , or Copper III nitrate. The purpose of this test was to determine whether my unknown formed a percipitate with this compound, and to eliminate cations.
2. If the reaction with is insoluble, it would allow me to eliminate suspected cations to get closer to the real cation. Since my cation for my unknown is soluble in most reactions, I attempted to mix it with Copper (II) nitrate, and compare them with the results of phosphate mixing with Copper (II) nitrate.
3. This test requires a spot plate cleaned with distilled water. Then, after adding 2 drops of to one section of the plate, add 2 drops of unknown H. Record results, and then compare with result of phosphate and . This double replacement reaction will yield and . It is possible to separate the two chemicals because nitrate is soluble and Copper is not.
4. C= cation A=anion
+ CA CuA (ppt) + C + (s) this reaction produced partially soluble percipitate with blue specks floating around.
5. By looking at my table of solubilities, it is possible to eliminate most cations because
b) Iron and Barium were present in unknown 3. Assigned unknown reacted with all 4 reactants and formed precipitate with 3 of them (Sodium carbonate, sodium hydroxide and Sulfuric acid). During the experiment it reacted very similarly to Iron (III) nitrate and Barium nitrate. For example, with it was tested against Ammonium Chloride, the color of the solution changed to a light green, very identically to Iron (III) nitrate and Ammonium Chloride. Besides, unknown 3 formed an orange brownish precipitate when it was tested with sodium carbonate. Iron (III) nitrate acted similarly. Moreover, unknown 3 reacted similar to Barium nitrate when it was tested against ammonium chloride and sulfuric acid. It did not form any precipitate with ammonium chloride but formed a very light white precipitate, which is identical to barium nitrate’s reaction against sulfuric acid. Therefore, the two present metal in unknown 3 are Iron and barium.
again I am going to assume this is soluble since I have not done it yet RC42 17 0 LC33 21 4 SC13 17 4Total 83 54 8
Put approximately 9-10(g) copper ore into beaker. Use spatula to break up any large pieces. Next add 17ml H2SO4 (aq) (hydro sulfuric acid) to the beaker. Began mixing until all or most traces of blue dissipate; or the copper ore will no longer dissolve (should appear as a milky liquid). Next use pipette to and remove solution and divide solution into 2 individual test tubes then Place test tubes into centrifuge and run centrifuge for 1 minute. Remove from centrifuge machine Fill a cuvette with the clear solution from the test tube making sure not to disturb the sediment at the bottom. Note the solution should bluish in tint Final place the cuvette in the colorimeter. Then record data and calculate in results section.
In order to test the hypothesis, the same tests given in Table 1 and Table 2 were performed on a sample of calcium nitrate. The results obtained for all the tests were the same as with our unknown compound. To further test this hypothesis, five different reactions were designed, as can be seen in Table 3, in which a
In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor
38. When naming binary ionic compounds, write the name of the positive ion (cation) first,
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.
This type reaction is known as a double displacement, where two ionic compounds, in this case lead nitrate, Pb(NO3)2(aq) and sodium iodide, NaI(aq), “change partners”. The cation (positive ion) of one compound combines with the anion ( negative ion) of the other to form two new compounds, one aqueous and one being an insoluble product known as a precipitate. To determine which product will be aqueous or a precipitate, the table of solubilities is used. This table helps predict which anions react with cations to produce either soluble or insoluble
When one looks back at the procedure of the experiment, trials 1, 2, 3, 4, 5, and 6 all use 6 M HCl for their reactions, and if this were to be substituted for 6 M HNO3, then these reactions would have still taken place, except in trial 2 because copper is less reactive than hydrogen in all cases, but their final observations may yield different colored solids and solutions (Beran,
Introduction: Using the analytical methods of Gas Chromatography and Mass Spectrometry, in order to determine the composition of a mixture and its individual pure compounds. This is done by analyzing the mixture of compounds using Gas Chromatography and the individual pure compounds by using Mass Spectrometry. Experimental Procedure: Obtain a screw cap and vial which will be ran in the Gas Chromatograph. Fill vial no more than half full of pre prepared unknown compound which is dissolved in either ethanol or acetone. Place vial in Gas Chromatograph and follow the instruction in order to analyze unknown compound.
RESULTS & DISCUSSION The purpose of this lab was to identify two different cations in an unknown solution by using qualitative analysis. The two methods of qualitative analysis explored in this lab were precipitation reactions and cation flame tests. If this lab were to be performed again, it would be beneficial to switch the order of Step 13 and Step 14 to confirm or deny the presence of calcium first before confirming/denying the presence of barium due to the possibility of a false positive from the barium.
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 solution went through this path exactly thus determining one of the cations was
In many cases, scientists don’t often have all the details when performing experiments, and there is almost always some aspect that is unknown. In certain scenarios, a chemist may not know what elements or compounds are present in a specific sample, so they must be able to recognize properties characteristic of certain elements and compounds, to determine their presence in the unknown sample. When working with unknown ions, it is often best to use known solubility rules to manipulate, separate, and identify the unknown ions present in a sample. In practice, this usually involves using specific reagents to cause some of the ions to fall out of solution as a solid precipitate, then separating the ions in the precipitate from the ions remaining in solution that are soluble with the specific reagents used. This process is repeated, causing ions to separate either by dissolving them in solutions that they are soluble in, or causing them to form insoluble compounds and fall out of solution as a solid precipitate until the ions have been isolated from each other. Once isolated, the ions are then treated with compounds which react in a distinct manner with specific ions, allowing their identities to be confirmed. In the first portion of this experiment ions are mixed in spot tests with separate reagents, specifically to observe and record the reaction that occurs. These observations can then be used to help
The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1.