Results:
Mass of copper wire: 0.28g
Mass of empty beaker: 68.49g
Mass of beaker and dry copper: 68.84g
Mass of recovered copper: 0.35g
Percent copper recovered: 0.35g / 0.28g * 100% = 125%
Observations:
When the 2.0 mL of concentrated nitric acid is poured onto the copper wire, the solutions turns green at first, with a lot of rust-coloured gas coming out the top. The solution slowly turns blue as the copper dissolves, and less gas is emitted. When the reaction is complete, Cu(NO₃)₂ is left in the solution.
When Cu(OH)₂ is added to the solution, the solution turns a darker blue and appears to have particles in it. Besides Cu(OH)₂, NaNO₃ has also formed in the solution. While heating the solution on the hot plate, the solution begins to turn darker in colour and gradually turns black. There appears to be solid particles in the solution. During the washing and decantation process, any excess NaNO₃ is removed from the solid CuO.
The
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This resulted from the copper not being completely dry before the final weighing. The copper clung to the porcelain dish when being transferred to the beaker to weigh, which most likely means there was still some remaining water and/or methanol on the copper that did not evaporate, resulting in an impossible recovery percentage. If this mistake had not been made, the full amount of copper would most likely not have been recovered. When washing, decanting, and transferring the copper from one container to another, it is next to impossible to recover all of the copper, especially when given time constraints. There is very little that can be done to prevent this other than careful transfers and
The purpose of performing the variety of tests that we did was to give more accurate results of what the unknown mineral was. By roasting the copper mineral, we obtained copper(II) oxide. This new sample came out of the crucible grayish-black. It was very brittle and full of cracks. This provided the percent composition that was necessary in finding the unknown mineral. When performing
Washing of the copper is necessary in this experiment to separate the iron from the copper and make sure the iron is not counted in the mass of the copper.
During the lab the staring copper reacted with 10 drops of nitric acid, creating a dark green liquid. Distilled water was added to increase the volume and turned the liquid into an electric blue. Then 10 drops of sodium hydroxide
Discard the solution in the appropriate container as directed to you by your lab instructor.
While this is reacting, it creates a gas called nitrogen dioxide. This is a gas that should not be inhaled at all. It is a very toxic gas. While adding the nitric acid to the copper, it should be done in a fume hood
Aqueous 3.0 molar ammonia was added, turning the solution a dark blue and forming a blue precipitate. The test tube was centrifuged for one minute to separate the solid from the liquid. The solid was saved and the liquid was placed into a clean test tube. To the solution, five drops of aqueous 6.0 molar nitric acid were added, as well as four drops of thioacetamide solution, turning the solution light green and producing a gelatinous precipitate. The test tube was then boiled for approximately four minutes. This caused a black solid to precipitate out, indicating that copper was the cation present. To confirm this, aqueous potassium iodide was added. This produced a dark drown precipitate, confirming copper as the cation
The anode and cathode are then placed in copper (II) sulfate solution. Copper ions leave the anode and are attracted to the cathode where the copper atoms latch on. The cathode increases in size as more and more of the copper atoms leave the anode. What is left behind of the anode is the impure metal forming a sludge of different metals beneath it.
The solution went from being black and cloudy to green and transparent, indicating that there is no longer a precipitate in the solution. In the fifth chemical reaction copper sulfate reacted with zinc resulting in this equation: CuSO₄(aq) + Zn(s) → Cu(s) + ZnSO₄(aq) This is a single displacement, redox reaction as zinc replaces the copper cation in copper sulfate resulting in metallic copper solid and zinc sulfate. This is evident from the observations as initially a black solid formed in the solution but as the hydrochloric acid was added and it reacted away the excess zinc
For this experiment, an electric hot plate was used to heat up the substances CuSO4 *5H20, and CaSO4*XH2O to determine the amount of moles of H2O when given in grams; in addition to the amount of percent error. 2.012g of CuO*5H2O was started with, and then after a few minutes of heating it on the electric plate, once it had turned almost white, it was then removed and weighed and it demonstrated that the mass had gone down to 1.179g, meaning, .833g of H20 was lost. For the CuSO4*XH20, there was no exact time as to when the mass has stopped changing but 2.046g of CuSO4*XH20, was measured out and heated for 20 minutes. At the end of the 20 minutes, the mass had gone down to 1.607g, resulting with 0.439 of H2O lost during the heating process.
“The Synthesis of alum crystals” Experimental 2 – The aim of the experiment is to prepare Alum (KAl(SO4)2.12H2O) from scrap aluminum. In order to speed up the reaction, the lacquer and paint of the scraped aluminum were cleaned and cut into smaller pieces and placed in a 250 ml beaker. After the addition of 50 ml of 1.4 M potassium hydroxide, the solution was heated for approximately 30 minutes. The color of the solution changes from light white to a dark grey solution. Once the solution is cooled down, it was filtered using a vacuum filtration.
Copper is the 29th element in the periodic table, located more specifically at group 11, period 4. Because of its chemical and physical attributes, it is a transition metal, which denotes high boiling and melting points. Both a conductor of heat and electricity, Copper is ductile and malleable. Its symbol “Cu” derives from the Latin cuprum. Copper is also valued for its two-for-one practicality: it is a vital nutrient that has antibacterial properties. Aside from what many people generally know about Copper (the “common knowledge,” so to speak), there is much information regarding its atomic buildup.
The correct theoretical empirical formula for the Hydrous Copper Sulfate solution is CuSO4 * 5H2O. From the data and results of calculation from this experiment, the empirical formula that was found during the process is CuSO4 * 5H2O. The sum of the percentage from the water, copper, and sulfate found in the solution added up to be 102%, a little over the normal 100%. From the least to greatest percentage of error, copper (Cu) with 2.291%, water (H2O) with 2.77%, and sulfate (SO4) with the greatest percentage of error of 3.691%. Overall, the percentage of error were made during this lab is acceptable. There could had been many type of error made during the process of this lab. One of the primary error that is most likely to be made while determining
When copper hydroxide is heated (in reaction 3), water is released as copper hydroxide decomposes into a second insoluble compound, copper(II) oxide. Copper(II) oxide, a base, then undergoes an acid-base reaction in reaction 4 with the addition of aqueous sulfuric acid, H2SO4 . The water-soluble salt, copper(II) sulfate, CuSO4 forms.
The objective of the lab is to recognize the importance of observation in the scientific method, merely applying the copper cycle and the process and reactions that take place throughout. Copper is present in several biological systems, having both biological and environmental implication. Sets of experiments will alter copper into nitrate salt, then a hydroxide, followed by an oxide and sulfate, before reaching the state of metallic copper once. These reactions are managed to test the copper in its ionic and the elemental kind, as well as any fluctuation of copper 's reactivity in different chemical environments.
Distilled water changed the color of copper (II) nitrate into a lighter shade of blue and diluted the solution.