Although sincepennies are actually made of zinc surrounded by a paper-thin copper foil to give them the traditional appearance of pennies. When the solution is diluted with water, water molecules displace the nitrate ions in the coordinate sites around the copper ions, causing the solution to change to a blue color.
Illustrate variety of substances of which an element can be part: Conservation of mass and of moles: We should recover as much copper as we started with. Same amount of copper present at every stage: Experience in standard chemical techniques: Actually, the nitrate ion oxidizes the copper metal to copper II ion while itself being transformed to NO2 gas in the process; the copper II ion then binds to six water molecules.
As a result, hydroxide ion can displace water from the copper II ion, yielding copper hydroxide, Cu OH 2, a blue precipitate.
We have seen this reaction before in the copper chloride lab. The pieces of wire are closer to 0. Use about ml of concentrated HNO3 solution.
Be careful with the nitric acid: If some copper remains undissolved by the time the production of gas is finished, then put the beaker on the hot plates in the hoods to hasten the reaction.
It is important to carry out this step in the fume hood because the brown NO2 gas is an irritant. Keep the mixtures in the hood until after you add the 10 ml of distilled water after completely dissolving the copper. Add the NaOH solution dropwise to the copper solution. After a blue precipitate is formed, periodically test the acidity of the solution by dipping your stirring rod into the solution and touching it to red litmus paper.
Try not to transfer the blue precipitate onto the litmus paper: The solution starts out acidic because of excess nitric acid from the previous step, so the first OH- added goes into neutralizing the acid; once the acid is neutralized, the next OH- added goes to forming the blue Cu OH 2 precipitate.
Only after that is finished does added OH- hang around idle, and only at that time will it turn red litmus paper blue. We want to make sure all the copper present is turned to Cu OH 2, so we add OH- until the solution turns the litmus paper blue.
Transform Cu OH 2 s to CuO s Add water to the reaction mixture obtained in the previous step, and add one or two boiling stones as well. Heat the contents of the beaker, but do not boil. Boiling makes the black CuO so fine that the filtration step is excessively long. Filter and wash the CuO as described in the procedure part C.
Keep the solid on the filter paper, and discard the filtrate.
Sulfuric acid solution is corrosive and will sting skin with which it comes into contact. Wash the copper metal three times with distilled water and transfer it to an evaporating dish as described in the procedure part Eand then wash it three times with 5-ml portions of isopropanol.
Washing with isopropanol will reduce the time needed for the drying step. Dry the copper over a beaker of boiling water as described in the procedure E.
Weigh the dry copper and record the mass. Compute the percent of copper recovered.Aimee Lorraine C. Capinpuyan Experiment No. 5 – Chemistry of Copper Locker # 7C Aug. 16, Abstract The objectives of this experiment were to recover the g Cu from the beginning of the experiment, and to classify the types of chemical reactions that took place.
Cu + HNO 3 - The solution became blue. All of the copper in precipitate form has been removed. Nitrogen gas was formed. Cu(NO3)2 - NaOH - A blue precipitate was formed. According to the definition given above, the following are the examples of reduction processes: 2 HgO (s) 2 Hg (l) + O2 (g) () (removal of oxygen from mercuric oxide) 2 FeCl3 (aq) + H2 (g.
From Copper to Copper Lab Shakil M, Horby L, Shaquile P, Fazal M April 17th Mr. Vu Chemistry Introduction Chemistry is the science of 5/5(4). The reactions you have mentioned are of the following type: Cu(s) + 4HNO3 (aq) → Cu(NO3)2 (aq) +NO2 (g) +H2O(l) Combination of Single Displacement or Substitution Reaction and Chemical.
Jan 04, · utilising the formulation: moles = mass/molecular mass, and as Cu has a molecular mass of sixty gmol-a million, you could calculate which you're utilising mol of Cu. From the stoichiometry on your equation, for each mole of Cu you acquire 2 Status: Resolved.