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Extracting Copper using Electrolysisyear10

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					Name……………………………                                       Form…………………………..


Extracting Copper using Electrolysis

An alternative method to extracting copper by reducing it with carbon is by
electrolysis. Electrolysis involves splitting the copper sulphate into copper and
oxygen by using electricity. Electrolysis is however expensive.




Method -
1.5 g of copper carbonate were weighed using a scale, and the mass (g)
recorded.
The copper carbonate was placed in a 250 ml beaker and 100 cm 3 of sulphuric
acid (0.75 mol dm-3) was added.
   1. What happened to the solution?

   …………………………………………………………………………………………
   …

   2. What colour change did you see?

   …………………………………………………………………………………………
   …

The equation for the reaction is

Copper carbonate + sulphuric acid copper sulphate + carbon dioxide + water
CuCO3             + H 2SO4            CuSO4        + CO2 +             H2O


   3. Use the equation above to work out what the blue solution is?

……………………………………………………………………………………………



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   4. Use the equation above to work out what the gas given off is?

……………………………………………………………………………………………


Two carbon rods were weighed and their mass recorded.



The carbon rods were then attached into the circuit above using crocodile clips.
A current of about 0.3 A was passed through the solution for 2 hours until it was
no longer blue and has turned into sulphuric acid.
The copper was washed with water and the carbon disposed off.
The copper was filtered using filter paper, and washed and dried as in the
previous method.
The actual yield was the mass of dried copper.


Equipment:
  5. List the equipment you will need…..




Results and observations


Oxidation is the loss of electrons
Reduction is the gain of electrons.

The copper sulphate solution contains the following ions in the solution.
Copper-            Cu 2+
Sulphate -         SO42-
Hydrogen ions-     H+
Oxygen ions -      O2-




                                      Unit 3                                        2
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Comlete the following equations and state whether they are reduction or
oxidation reactions.

    6. Copper ions lose electrons to make copper atoms

    Cu2+ + 2e- ................

    this is a …………………….. reaction

    7. Oxygen ions gain electrons to make oxygen atoms

    O2-   -      2e- ................

    this is a …………………….. reaction

    8. Hydrogen ions lose an electron to make a hydrogen atom

    H+ + e- ................

    this is a …………………….. reaction

    9. As both reduction and oxidation reactions occur, this is a

    ……………..reaction.

Observations

    10. At the positive electrode (a……………) there were lots of bubbles of
        …………………….
    11. At the negative electrode (c………….) there were afew of bubbles of
        ……………………. And a lot of the metal ………………………………..

    12. The carbon rod at the anode wasted away as the oxygen reacted with the
        carbon

to make the gas …………….                   ……………………….

Results

Mass of carbon rod attatched to positive terminal of powerpack=…………..g
Mass of carbon rod attatched to negative terminal of powerpack=…………..g
Mass of filter paper =……………..g
Mass of filter paper + copper =……………..g
Mass of copper =………………….g




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Why do you think the copper produced using this method is purer than you other
method where you used carbon? (Hint pure copper is pink)

Comparing the two methods of copper extraction (electrolysis and carbon)

Actual Yield produced using heat to extract copper =……….%
Actual Yield produced using electrolysis to extract copper =……………..%


Percentage Yield produced using heat to extract copper =……….%
Percentage Yield produced using electrolysis to extract copper =……………..%


Which method was better and why?




                                   Unit 3                                        4
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Explain what happens during the electrolysis of copper

Experiment 3 - Purification of copper

One of the problems with both experiments is that the copper is impure. In other
words it has bits of carbon in it. To make the copper pure we use electrolysis,
but with copper electrodes rather than carbon electrodes. The Impure copper at
the positive terminal called the a…………….. turns into copper ions. These
copper ions are deposited at the negative terminal called the c………………..
making pure copper.




Extension
Explain how purification takes place in your own words…………
An anode and a cathode are placed into the solution, connected to a battery, and
current passed through. The electrodes are copper. The Copper at the positive
electrode (anode) lose 2 electrons to make Cu2+ ions this is a ………………..
reaction. These Cu2+ ions then migrate to the cathode and picks up 2 electrons
to make copper Cu. Impurities are dropped at the bottom of the beaker.
 Write out electron loss/gain equations for the anode and cathode.




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                                         Costings

“Direct costs” – those arising from the cost of the production of the product e.g. raw
materials, heat energy or electricity used in reaction.
“Indirect costs” – equipment and maintenance costs with labour costs- these will
contribute to overall production costs.


Item             Cost             Ammount I         My cost          Direct/Indirect
                                  used                               cost
Copper         £10.20 per
carbonate      500g
Carbon         £2.00 per
               500g
Test tube      £0.18
Beaker         £2.00
Gas            £0.8 per
               hour
Filter paper £1.30 for
               100 circles
Labour         £5.00 per
               hour
Total cost to make 1.5g copper =
Total cost to make 1.0g copper =




                                        Unit 3                                           6
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Industrial Process - Manufacturing Metals by Redox Reactions




Compare this method to the method you used
Comparison                  Our method        Industrial method
Purity of copper „ore‟




Amount of copper ore used

Amount of copper made


Temperature used


Purity of copper made




                                    Unit 3                        7
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Compare Electrolysis method to using heat to extract carbon method

Comparison                   Using heat to extract copper   Using carbon to extract
                                                            copper
Raw Materials



Actual yield

% Yield

Relative purity of copper
made


Relative energy cost



Advantages



Disadvantages




                                      Unit 3                                          8

				
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posted:11/20/2011
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