Copper to Copper LabsCopper to Copper LabMonday, December 7, 2012Copper was one of the first metals to be isolated, due tothe ease of separating it from itsores. It is believed that the process was known(metallurgy) as early as 4500 BC.It is a ductile,malleable metal and is easily poundedand/or drawn into various shapes for use as wire,ornaments and implements of various types.
Alloys of copper (bronze, brass) were discoveredquiteearly in history and were among the firstimpetuses for international trade.Pure copper isthe best electrical conductor of the moreabundant metals.It has a good thermal conductivityand is corrosionresistant.Copper as a metal is second in commercial importanceonly to iron.In this experiment, a weighed amount of copper metal istransformed, through a series ofreactions, into other copper-containing compounds, andis eventually returned to the metal state.The series involves the use of reactions classified asmetathesis, decomposition, displacementand oxidation-reduction reactions.Cu (s) + HNO3 (aq)<-> Cu(NO3)2 (aq) + NO2 (g) + H2O (l)Cu(NO3)2 (aq) + NaOH (aq) <-> Cu(OH)2 (s) + NaNO3 (aq)Cu(OH)2 (s) <->CuO (s) + H2O (l)
CuO (s) + H2SO4 (aq) <->CuSO4 (aq) + H2O (l)CuSO4 (aq) + Zn (s) <-> Cu (s) + ZnSO4 (aq)This series of reactions begins and ends with coppermetal.DOUBLE REPLACEMENTIt is a transfer of electrons and these particular productsformed because Cuhas a positive 2 charge and NO3 has a negative 1 charge.When mixed with NaCl(both Na and Cl have a positive and negative 1 charge)the electrons transferand form the products.Cu(s) + 4HNO3(aq) --->Cu(NO3)2(aq) + 2H2O(l) + 2NO2(g)
Emma is striving for accuracy by rinsing the beakerssides to collect all thecopper sediments.Cupric nitarate solution reacts with aqueous sodiumhydroxide and produces bluecupric hydroxide and sodium nitrate.Waliis striving for accuracy by seeking to findthe exact measerment of the liquid to pour into thegraduated cylinder.
Solid copper is reacted with nitric acid, becoming a bluesolution of aqueous cupric nitrate and H2O, and a brown,poisonous gas: nitrogen oxide.THIS IS A DOUBLE REPLACEMENT REACTION:
At room temperature, with stirring, carefully add 6MNaOH solution dropwise until thesolution is basic to red litmus paper. Use a capillary tubeto remove sample for pH testing.Cu(NO3)2 (aq) + NaOH (aq) <-> Cu(OH)2 (s) + NaNO3 (aq)Alight blue precipitate of copper(II) hydroxide is formedas this reaction is carried out
Cu(OH)2(s) --->CuO(s) + H2O(l) Blue cupric hydroxide is decomposed by heating to formsolid black cupric oxideDuring this time, the copper(II) hydroxide is transformedinto copper(II) oxide (or cupricoxide), which appears as a black precipitate. When nomore blue precipitate is present, allow themixture to cool to room temperature and remove themagnetic stirring bar using forceps.Ifnecessary, rinse the bar with a small amount of water,collecting the rinse in the beaker.Isolatethe black solid by suction filtration using a Hirschfunnel.
SINGLE REPLACEMENTThe driving force behind this reaction was the formationof a solid.
When CuSO4 reacted with Zn, it became ZnSO4 andformed the solid copper.Cu3(PO4)2(s) + 3H2SO4(aq) ---> 3CuSO4(aq) +2H3PO4(aq) This is an acid based neutralization reaction as we poursulfiric acid on tosolid cupric phosphate, which produces a blue cupricsulfate solution andphosphoric acid.During the filtratraion process Emma pointed out that welost a few drops ofthe solution. She was striving for accuracy by using apipette to get the dropsback.
NEXT:CuO (s) + H2SO4 (aq) <->CuSO4 (aq) + H2O (l)Preparation of Copper(II) Sulfate SolutionPlace 6 mL of 3M sulfuric acid in a 50 mL beaker. Using aspatula, transfer the blackcopper oxide and filter paper to the acid solution.Stir the mixture with a glass stirring rod untilthe blacksolid has completely dissolved.Remove the filter paper from the solution, as soon asit is clean, using forceps.Gently rinse the filter paper with 1 - 2 mL of water.Add the rinse tothe blue copper(II) sulfate solution.If residual traces of the CuO remain on the Hirsch funnel,rinse or dissolve this material (holding the funnel overthe beaker), using the solution in the
beaker.Once the transfer is complete, rinse the funnel with 1 - 2mL of water.This rinse is alsoadded to the beaker.Remember to work together!!!Regeneration of Copper Metal CuSO4 (aq) + Zn (s) <-> Cu (s) + ZnSO4 (aq)
SINGLE REPLACEMENTThe driving force behind this reaction was the formationof a solid.Place the beaker containing the blue copper(II) sulfatesolution in the HOOD and add, insmall portions, about 600 mg(0.600 g) of zinc powder.Stir the mixture with a glass rod, untilevolution ofbubbles ceases.The blue color should now be gone. A metallic precipitateofcopper metal forms during this period.Vigorous evolution of hydrogen gas is also observedduring the addition.