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Analysis Of Copper Lab Report

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The aim of this experiment is to follow the elemental copper through a series of physical and chemical changes as a result of various chemical reactions all of which will be classified according to the type of reaction. In addition, the resulting copper was returned to its elemental state was weighed and the per cent recovery of pure copper was calculated. The first reaction that took place in the copper cycle was the addition of 16.0M Nitric Acid to the copper wire.ii iii iv v This reaction resulted in the wire being covered in bluish-green bubbles, the solution of nitric acid turning emerald green, and the production of a yellow-brown, foul smelling gas, NO2. This reaction had to be performed in the fume hood because the gas given off by …show more content…

The colour change and the production of NO2 gas are strong indicators of chemical reactions in addition to the resulting warmth of the beaker, indicating that the addition of nitric acid to elemental copper is an exothermic reaction. The second reaction consisted of adding 3.0M NaOH to the solution in order to form Cu(OH)2.ii iii iv v The resulting solution turned a dark, royal blue colour as well as becoming cloudy and opaque as a result of a precipitate being created. The beaker was also hot during the reaction, implying an exothermic reaction took place. The heat, colour change, and formation of a precipitate all signs of a chemical reaction. The third reaction consisted of heating the resulting solution on a hot plate for twenty minutes while stirring, resulting in the formation of CuO.ii iii iv v While heating, the solution changed from the previous royal blue colour, to a brownish-black coloured solution with more visible chunks. When …show more content…

In relation to this experiment, the per cent recovery, or “how much of the original pure copper mass recovered at the end of the experiment”ii iii iv v should be 100% because all of the copper should return to elemental form. However, the per cent recovery from this experiment was calculated to be 56.5% recovery, much lower than the anticipated value, and therefore does not appear to support the Law of the Conservation of Mass. One explanation for the per cent recovery being too low would be that some copper was lost while decanting the solution after reaction three. The time constraints also should be taken into consideration, as if the reaction resulting in the precipitation of copper by the aluminium wire was allowed to run longer, more of the copper could have been precipitated out of solution, closing the gap toward the 100% recovery. The product of the reaction was a dark reddish brown colour. This could have been the result of the sample still containing some of the CuSO4 that was not washed off and therefore, resulting in a darker colour. The copper could have also been slightly overheated when using the steam bath, thereby leading to tarnishing on some copper as a result of oxidation with the air making it slightly impure and darker in

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