Copper Cycle Lab

Introduction Copper is an extremely significant element in many ways whether it be biological, environmentally, or even economically, and each of its many forms has unique characteristics that serve many different purposes. In this experiment, chemical reactions were conducted on copper that represented its reactivity in different chemical environments. Therefore, the purpose of this experiment was to explore the copper cycle through the identification of different reaction types that occurred in it and that eventually lead up to the regeneration of the original product.
Materials and Methods The preparation of the experiment started off by placing a hot plate on a ring stand. A 50 mL beaker was then attached to the iron ring and placed …show more content…
In the first step of the cycle, about 5 mL of 6 M HNO3 were added to the beaker containing the 0.2471 grams of copper turnings. In the reaction that followed, the copper turnings dissolved as the solution turned green and eventually light blue accompanied by a small sizzle. The chemical reaction that took place here was Cu(s) + 4 HNO3(aq)  Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O. This was a redox reaction because oxidation occurs. This was proven from the reaction because copper was oxidized by the nitric acid when the copper turnings chemically combined to the acid with oxygen. The equation demonstrated this with the transferring of electrons, which revealed the change in the oxidation state of copper. In the second step of the cycle the color of the solution changed from blue to green after 55 drops of 6 M NaOH3 were added. There were also blue pieces of solid that began to form. When 85 drops were added, the liquid was now a dark blue. However, it wasn’t until 99 drops were added when the litmus paper turned blue when coming in contact with the solution. The chemical reaction that took place was Cu(NO3)2(aq) + 2 NaOH(aq)  Cu(OH)2(s) + 2 NaNO3(aq) and was a metathesis reaction because a precipitate was formed. The precipitate was evident from the solid blue pieces of Cu(OH)2(s) that formed in the solution. This double displacement reaction was also supported from the equation when copper and sodium switched places in the products. In the third step of the cycle, after setting the heat to 355°, small amounts of a dark solid began to form at the bottom of the beaker. The liquid gave off steam, began to bubble, and turned a blackish color after a few minutes. After the solution cooled down, a dark black/brown precipitate was seen settled at the bottom portion of the beaker. In the fourth step of the cycle, the liquid was decanted and 10 mL of distilled water was added. After