For this experiment, Cu(s), went through many reactions with a series of reagents to produce four different copper containing compounds before being restored back to its original metallic form. The observations from each reaction were then used to determine the type of reaction it was, and various equations associated with each reaction type. The amount of copper measured at the beginning and end of the experiment were compared to one another to determine its percent recovery by using Equation 1. The percent recovery was then related back to the Law of Conservation of Mass to see if the experiment supported the law. One thing that could be changed with this experiment would be to have a proper way to decan the liquids since some of the precipitate …show more content…
Chemical Equations for Reaction 1 Chemical Equation Cu(s) + 4HNO3(l) -> Cu(NO3)2 + 2NO2(g) + 2H2O(l) Reduction Half-Reaction 2H+(aq) + 2NO3-(aq) + 2e- -> 4NO2 + 2H2O (l) Oxidation Half-Reaction Cu(s) -> Cu2+ + 2e- Reducing Agent Cu(s) Oxidizing Agent NO3-(aq) For reaction 2, the solution’s color changed form a transparent lighter blue to particles containing a cloudy vibrant blue color, thus creating a precipitation reaction. This was created from the addition of NaOH. Cu(OH)2 was formed from this reaction because the Cu2+ ions in reaction one’s solution combined with the OH- ions that were separated from NaOH which is a soluble strong base. The precipitate was the consistency of gel whose color was blue. Table 2 seen below contains the balanced formula unit, total ionic, and net ionic equations. Reaction 2 was a precipitation reaction that was exothermic because the energy was released to the surroundings due to formation of strong bonds used to create the precipitate. This reaction occurred without the use of any outside source of heat. Table 2. Chemical Equations for Reaction 2 Formula Unit Equation Cu(NO3)2(aq) + 2NaOH(aq) -> Cu(OH)2(s) + 2NaNO3(aq) Total Ionic Equation Cu2+ + 2NO3- + 2Na+ + 2OH- -> Cu(OH)2(s) + 2Na+ + …show more content…
Tiny black-brown particles that looked like dirt eventually appeared throughout the course of the reaction. Once the liquid surrounding the particles became clear, the beaker was removed from the hotplate and the particles settled at the bottom of the beaker where the water was decanted. The particles looked airy and light. The Cu(OH)2 reacted because the of the heat added to the solution which caused the solution to be broken down. Therefore, this was caused by a decomposition reaction. The copper hydroxide decomposed into solid copper oxide and water. Table 3 below contains the balanced chemical