The word chemistry was most likely taken from the Greek ??

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CH 103 A SERIES OF CHEMICAL REACTIONS,THE COPPER
CYCLE

• The word chemistry was most likely taken from the
  Greek ??µe?a (chemeia) which means to pour metals
  together.
• A chemist studies the transformations of matter
  at the atomic and molecular scales.
• The Discovery of Phosphorus was painted by
  Joseph Wright of Derby in 1771.
• Phosphorus was discovered by Hennig Brand in 1669.

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STEP 1 PREPARATION OF Cu(NO3)2 FROM Cu

• Accurately weigh 0.5 grams of copper wire to 3
  significant digits. Record this mass in your
  data sheet. For example, this wire might weigh
  0.512 g.
• Perform the rest of this step in a FUME HOOD.
• Place the Cu wire in a 250 mL beaker and
  CAREFULLY add 10 mL of 16 M (concentrated) nitric
  acid (HNO3). The copper wire should begin to
  dissolve almost immediately. If necessary,
  carefully warm the reaction mixture on a hot
  plate.
• The blue color is due to copper(II) nitrate
  (Cu(NO3)2) and the brown fumes are nitrogen
  dioxide (NO2).
• Cu(s) 4HNO3(aq) ? Cu(NO3)2(aq) 2NO2(g)
  2H2O(l)
• The reactant, Cu metal. The product,
  Cu(NO3)2.

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STEP 1 PREPARATION OF Cu(NO3)2 FROM Cu

• Cu(s) 4HNO3(aq) ? Cu(NO3)2(aq) 2NO2(g)
  2H2O(l)
• This is an oxidation-reduction reaction. That
  is, electrons are transferred from 1 reactant to
  another reactant.
• Oxidation is a loss of an electron or electrons
  by an atom or group of atoms.
• Reduction is a gain of an electron or electrons
  by an atom or group of atoms.
• In this reaction, Cu(0) is oxidized to Cu(II),
  and N(V)O3- to reduced to N(IV)O2.

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STEP 2 PREPARATION OF Cu(OH)2 FROM Cu(NO3)2

• Dilute your solution to 100 mL with distilled
  water.
• You may now move from the fume hood to your
  laboratory bench.
• Cautiously add 30 mL of 6 M (dilute) sodium
  hydroxide (NaOH) to this solution.
• Use a stirring rod to transfer a drop of this
  solution to a piece of red litmus paper. This
  litmus paper will turn blue in a basic solution.
  If it is not basic, add more 6 M (dilute) NaOH
  until the solution turns red litmus paper blue.
• The products of the reaction are the pale blue
  solid copper(II) hydroxide (Cu(OH)2) and a
  colorless solution of aqueous sodium nitrate
  (NaNO3).
• You will use any changes in color and solubility
  to write a balance equation for this reaction.

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STEP 3 PREPARATION OF CuO FROM Cu(OH)2

• Use a Bunsen burner to carefully heat your blue
  Cu(OH)2 solution until it is converted to a
  mixture of black CuO and H2O.
• Stir constantly when heating.
• Do NOT let the mixture boil vigorously.
• This process should take about 5 minutes.
• The product, CuO.
• You will use any changes in color and solubility
  to write a balance equation for this reaction.

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STEP 4 PREPARATION OF CuSO4 FROM CuO

• Let the CuO settle.
• Carefully decant and discard the liquid.
• Use a Bunsen burner to heat 200 mL of distilled
  water.
• Use approximately 1/3 of this very hot distilled
  water to rinse your CuO. Then discard this
  rinsate. Repeat this process until all of the
  200 mL of distilled water is gone. This is
  called the method of successive dilutions. It is
  used to remove any residual nitrate that might be
  leftover from Step 1. If you do not do this
  your yield of copper will suffer.
• Add 15 mL of 6 M (dilute) sulfuric acid (H2SO4)
  to the CuO. If necessary, add more H2SO4 until
  all the black CuO has dissolved to yield a blue
  solution of copper(II) sulfate (CuSO4).
• The product, CuSO4.
• You will use any changes in color and solubility
  to write a balance equation for this reaction.

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STEP 5 PREPARATION OF Cu FROM CuSO4

• Add 2 g of zinc (Zn) metal to the CuSO4 solution.
  Stirring occasionally until the solution becomes
  colorless. Adding more Zn will quicken this
  process however, adding too much Zn should be
  avoided because it will have to be removed later.
• The beaker has both Cu and Zn metal. Add 10 mL
  of distilled water, 8 mL of 6 M (dilute)
  hydrochloric acid (HCl), and stir to dissolve the
  excess Zn. Gently warm this solution with a
  Bunsen burner to speed up the dissolution of Zn.
• Hydrogen (H2) gas is evolved as follows
• Zn(s) 2HCl(aq) ? ZnCl2(aq) H2(g)
• (This is another example of an oxidation-reduction
  reaction.)
• The reaction is done when the bubbles of H2 gas
  stop.
• When this reaction is done, let the solid Cu
  settle and decant the liquid.
• Use two 50 mL aliquots of distilled water to
  rinse the Cu. Discard the rinsate. Be careful
  not to lose any Cu.

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STEP 6 DRYING Cu METAL

• Record the weight of an evaporating dish.
• Use a rubber policeman to transfer the Cu metal
  and as little water as possible to the weighted
  evaporating dish.
• Use a boiling water bath to gently dry the
  sample.
• Do NOT heat the Cu to dryness in flame. The Cu
  will react with air to make CuO.
• Let the evaporating dish to cool to room
  temperature.
• Record the combined weigh of the dish and Cu.

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SAFETY

• Give at least 1 safety concern for the following
  procedures that will be used in todays
  experiment.
• Heating glass with a hot plate or a flame.
• Injury from a burn or causing a fire. Be
  careful. Do not wear loose clothing or long
  hair. Glass can shatter when heating wear your
  goggles at all times.
• Using 16 M HNO3, 6 M NaOH, 6 M H2SO4, 6 M HCl,
  and Zn.
• These are irritants. Wear your goggles at all
  times. Immediately clean all spills. If you do
  get either of these in your eye, immediately
  flush with water.
• Generating H2O(g) and acidic gases.
• Again, these are irritants. Wear your goggles at
  all times. Use the fume hood when handing 16 M
  (concentrated) HNO3. Immediately clean all
  spills. If you do get either of these in your
  eye, immediately flush with water.
• Your laboratory manual has an extensive list of
  safety procedures. Read and understand this
  section.
• Ask your instructor if you ever have any
  questions about safety.

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SOURCES

• Amethyst Galleries, Inc. 2006. Copper (Cu).
  http//www.galleries.com/minerals/elements/copper/
  copper.htm Available accessed 18 September
  2006.
• Barnes, D.S., J.A. Chandler. 1982. Chemistry
  111-112 Workbook and Laboratory Manual. Amherst,
  MA University of Massachusetts.
• Hong Qing Chemcial. 2006. Copper Sulfate
  Pentahydrate. http//www.hongqingchem.com/copper2.
  htm Available accessed 18 September 2006.
• Joseph Wright of Derby. 1771. The Discovery of
  Phosphorus.
• JunCheng International. 2006. Copper(II) nitrate,
  trihydrate. http//www.czlthg.com/web/2/index43.ht
  m Available accessed 18 September 2006.
• JunCheng International. 2006. Copper(II) oxide.
  http//www.czlthg.com/web/2/index44.htm
  Available accessed 18 September 2006.
• Unknown. 2006. Etymology of Alchemy.
  http//en.wikipedia.org/wiki/Chemistry Available
  accessed 18 September 2006.
• Weast, R.C, M.J. Astle, W.H. Beyer. 1983. CRC
  Handbook of Chemistry and Physics. Boca Raton,
  FL CRC Press, Inc.