Copper to Copper Labs

Copper to Copper Lab

Monday, December 7, 2012

Copper was one of the first metals to be isolated, due to the 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 pounded and/or drawn into various shapes for use as wire,ornaments and implements of various types.

Alloys of copper (bronze, brass) were discovered quite early in history and were among the first impetuses for international trade.

Pure copper is the best electrical conductor of the more abundant metals.

It has a good thermal conductivity and is corrosion resistant.

Copper as a metal is second in commercial importance only to iron.In this experiment, a weighed amount of copper metal is transformed, through a series ofreactions, into other copper-containing compounds, and is eventually returned to the metal state.The series involves the use of reactions classified as metathesis, 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 copper metal.

DOUBLE REPLACEMENT

It is a transfer of electrons and these particular products formed because Cu

has 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 transfer

and form the products.

Cu(s) + 4HNO3(aq) --->

Cu(NO3)2(aq) + 2H2O(l) + 2NO2(g)

Emma is striving for accuracy by rinsing the beaker's sides to collect all the

copper sediments.

Cupric nitarate solution reacts with aqueous sodium hydroxide and produces blue

cupric hydroxide and sodium nitrate.

Wali is striving for accuracy by seeking to find

the exact measerment of the liquid to pour into the graduated cylinder.

Solid copper is reacted with nitric acid, becoming a blue solution of aqueous cupric nitrate and H2O, and a brown, poisonous gas: nitrogen oxide.

THIS IS A DOUBLE REPLACEMENT REACTION:

Cu(NO3)2 (aq) + NaOH (aq) Cu(OH)2 (s) + NaNO3 (aq)

At room temperature, with stirring, carefully add 6M NaOH solution dropwise until thesolution is basic to red litmus paper. Use a capillary tube to remove sample for pH testing.

Cu(NO3)2 (aq) + NaOH (aq) <-> Cu(OH)2 (s) + NaNO3 (aq)

A light blue precipitate of copper(II) hydroxide is formed as this reaction is carried out

NEXT IS A Decomposition reaction

Cu(OH)2(s) ---> CuO(s) + H2O(l)

Blue cupric hydroxide is decomposed by heating to form solid black cupric oxide

During this time, the copper(II) hydroxide is transformed into copper(II) oxide (or cupricoxide), which appears as a black precipitate. When no more blue precipitate is present, allow themixture to cool to room temperature and remove the magnetic stirring bar using forceps.

If necessary, rinse the bar with a small amount of water, collecting the rinse in the beaker.

Isolate the black solid by suction filtration using a Hirsch funnel.

and water.

SINGLE REPLACEMENT

The driving force behind this reaction was the formation of a solid.

When CuSO4 reacted with Zn, it became ZnSO4 and formed the solid copper.

Cu3(PO4)2(s) + 3H2SO4(aq) ---> 3CuSO4(aq) + 2H3PO4(aq)

This is an acid based neutralization reaction as we pour sulfiric acid on to

solid cupric phosphate, which produces a blue cupric sulfate solution and

phosphoric acid.

During the filtratraion process Emma pointed out that we lost a few drops of

the solution. She was striving for accuracy by using a pipette to get the drops

back.

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 a spatula, transfer the blackcopper oxide and filter paper to the acid solution.

Stir the mixture with a glass stirring rod untilthe black solid 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 to the blue copper(II) sulfate solution.

If residual traces of the CuO remain on the Hirsch funnel,rinse or dissolve this material (holding the funnel over the beaker), using the solution in the

beaker.

Once the transfer is complete, rinse the funnel with 1 - 2 mL of water. This rinse is also added to the beaker.

Remember to work together!!!

Regeneration of Copper Metal

CuSO4 (aq) + Zn (s) <-> Cu (s) + ZnSO4 (aq)

SINGLE REPLACEMENT

The driving force behind this reaction was the formation of a solid.

Place the beaker containing the blue copper(II) sulfate solution in the HOOD and add, insmall portions, about 600 mg(0.600 g) of zinc powder.

Stir the mixture with a glass rod, until evolution of bubbles ceases.

The blue color should now be gone. A metallic precipitate ofcopper metal forms during this period.

Vigorous evolution of hydrogen gas is also observedduring the addition.