Purpose: Metal cations can have a precipitation reaction, oxidation-reduction reaction, or complex ion formation reaction based on the ions they are reacting with. Using these potential characteristics, qualitative analysis was performed to identify the metal cations present in an unknown solution.
Procedure: For parts A and B of the experiment, please refer to “Qualitative Determination of Selected Metal Cations.” Chemistry 1210: General Chemistry Laboratory Manual, Hayden McNeil, Plymouth, 2018, pp. 103-104. for the proper procedure.
Procedure: Part C
To begin, a test tube was filled approximately ¼ of the way full with Na2SO4. Next, two drops of the unknown substance were added to the Na2SO4 solution. Almost identically, another test
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Cloudy at the bottom of the test tube.
Cu2+ Solution changed to a light blue, water consistency White dust accumulated at the bottom of test tube, surrounded by watery consistency with shades of sunset orange and yellow throughout Precipitate formed with a light blue color, small separation in the liquid with no change in color. Separation occurred closer to the bottom of the test tube.
Fe3+ No reaction Initially burnt orange, more clear color toward the bottom of the test tube. After some time passed, light pink towards the bottom and deeper red Bubbling occurred, light yellow towards the top of the solution, normal consistency, then became gelatinous
Mn2+ No reaction No reaction Beige dust at bottom of test tube, surrounded by a cloudy solution
Pb2+ White powder accumulated at the bottom of test tube, small white particles floated throughout, reaction similar to a snow globe Liquid water consistency, sunshine yellow with sparkly yellow dust throughout, dust collected at bottom. After addition of 1,2-dichloroethane, color remained, a bubble dropped towards the bottom of the test tube
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After a few minutes, separated into a rose brown solution and clear, solution. Brown pieces became blue/almost white (looks like sugar dissolved in liquid) Brown/rose gold liquid, “sand” of the same color at the bottom of the test tube, appeared foggy. Slimy/watery consistency, a shade of blue green Liquids separated, light orange in ¾ of the test tube, blue green shade consumed ¼ of the test tube. Dust like particles throughout the solution.
Cu2+ Blue solid (baby blue/brown), surrounded by clear solution, more liquid consistency towards the top of the test tube Sky blue liquid around precipitate, brown line in precipitate became more distinct Consistency of water, liquid became royal blue, small particles present Three shades of blue became observable, with the light/baby blue being the color at the bottom
Fe3+ Burnt orange liquid (consistency of water), small pieces of the same color at the bottom. Test tube felt warm at the touch. Solution appeared burnt orange and wispy throughout the bottom of the test tube, also burnt orange on top of solution Solution had a darker yellow tint, pale shade. Had a consistency similar to water Burnt orange precipitate towards middle, clear liquid more towards the bottom of the test
Next prepare the third test tube with an accurate measurement of 5ml sodium carbonate once again labelling appropriately.
1. The first experiment is Preparation of a Cobalt Amine Bromide Product ; Synthesis #3 was used to create the compound. Added 5 grams of cobalt carbonate to 20 mL of hrdrobromic acid in a beaker. Noticied a slight color change to dark purple. Solution frothed after it settled I mixed in 15mL water and
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.
In the fume hood, 3 mL of a 15 M concentrated ammonia solution was added to each volumetric flask. The flasks were swirled until all solids were dissolved. Each flask was diluted to volume with distilled water, covered with Parafilm, and mixed. The concentration (in g/L) of Cu2+ was calculated in each of the six standard solutions.
8. The Tubes were observed for a final 5 minutes, noting any color changes in the solutions.
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.
CH 204 – Introduction to Chemical Practice Experiment #1– (Qualitative Analysis of Cations) Ashley Gilbert* Claire LeBovidge TA: Ravi Teja February 15, 2017 RESULTS & DISCUSSION The purpose of this experiment was to have found the identity of unknown cations having used qualitative analysis. The unknows were composed of metal nitrate salts and contained either lead or silver and calcium or barium. Also, cation flame test was performed to test and observe the color the flames turned when a wooden stick, dipped in a metal chloride solution, was waved over the flame. If this experiment was to be repeated, a way to improve the current procedure might be to describe exactly what the test tubes should look like in steps that may be confusing, for example in step 11, it
The lab performed required the use of quantitative and analytical analysis along with limiting reagent analysis. The reaction of Copper (II) Sulfate, CuSO4, mass of 7.0015g with 2.0095g Fe or iron powder produced a solid precipitate of copper while the solution remained the blue color. Through this the appropriate reaction had to be determined out of the two possibilities. Through the use of a vacuum filtration system the mass of Cu was found to be 2.1726g which meant that through limiting reagent analysis Fe was determined to be the limiting reagent and the chemical reaction was determined to be as following:-
Similar data have also found in 2B and 2C. These two groups of reaction both contain a similar element in the solution, so it might be the reason to cause the solid form in similar colors. The reaction of 1D also become a precipitate, but appeared in a different color. For 3C, the result was not clear enough to make sure if a precipitate was formed or not, but after a while, the solution turned slightly foggy. Solution 2D, 3D, and 4D had no color change, therefore no precipitation was formed.
The color of the solution was turning slightly into yellow and the color of the iron strip into white.
When two solutions combine and a solid substance is formed, this solid is called a precipitate. In your experiments, if the clear reactant solutions you combined together formed a cloudy product, then a precipitate (solid substance) was formed. Describe the precipitates (according to color and clarity) and the substances that formed them. (18 points) The combinations that formed precipitates in my experiment were MgSO4 and NH3, MgSO4 and Na2CO3, Na2CO3 and CH3COOH.
When the zinc was added to the copper (II) sulfate solution, the solution started to bubble. As the solution was stirred, it turned a cloudy blue. Small flecks of a brown solid were visible. As the solution became colorless, the brown solid settled to the bottom of the beaker. The solid formed was copper in its elemental state. The color faded from the solution as the copper ions slowly formed into solid copper. The copper was poured into a funnel with filter paper and washed three times with 25 mL
At the end of the experiment when the lid was removed, it was found out that the blue colour of the copper (II) sulphate solution has faded away. It was turned to pale grey and there were some precipitates present. It was the zinc powder that was in excess to ensure that the copper (II) sulphate solution could react fully with the zinc powder.
Product bubbled upon addition to the hydrochloric acid; liquid turned cloudy ¡V precipitate was present; zinc sample disintegrated slowly and turned black in color.
0.5% of copper sulphate solution was added by drop at a time and and the test tube was shaked continuously.