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A-5
EXPERIMENTAL PROCEDURE
Part I. Copper(II) nitrate from Copper Metal.
Remember to put on your safety glasses as soon as you enter the chemistry laboratory.
Using the correct weighing technique demonstrated by your laboratory instructor (and outlined on page 17
of the Laboratory Manual), accurately weigh about 1.1 grams of copper powder (about the size of a pea)
into a 150 mL beaker. Remember to NEVER transfer chemicals when the beaker is on the analytical
balance. Put any excess copper metal in the bottle marked “waste copper” or “solid chemical waste”. Do
not put excess copper back in the reagent bottle.
Label your beaker with your name, then using the automatic dispenser, add 10.0 mL of 6.0 M HNO3
directly into your beaker. This addition must be done in the fumehood! Set the beaker on the
fumehood surface for about 30 seconds until the vigorous bubbling has subsided. Next, place the beaker on
the hot plate and continue to heat until all the copper has reacted. If the copper has not dissolved in 5
minutes, add another 1-2 mL of 6.0 M HNO3 to the solution and reheat. Record your observations on the
Observations Sheet. It is possible that during this step, a trace of black residue may form in your solution.
This residue will be removed in the final step of the experiment.
While the copper metal is dissolving, prepare an ice bath in a small plastic container using three parts
crushed ice to one
part cold
tap water. Place a wash bottle half filled with deionized water in the ice bath
to cool. This cold deionized water will be used later to wash the copper(II) carbonate (CuCO3) precipitate
in Part II.
Once all of the copper metal has dissolved, allow the copper(II) nitrate solution to cool in the ice bath for 5
minutes before going on to Part II.
Part II. Copper(II) carbonate from Copper(II) nitrate.
Measure out 20 mL of 2.0 M Na2CO3 into your 50 mL graduated cylinder. Add this solution carefully
(avoid splattering) to the cold copper(II) nitrate solution. Gently stir the solution
while adding the
Na2CO3. Note that a colorless gas is given off in this reaction. Place this reaction mixture in the ice bath
