Experiment – Making ionic compounds
AIM
To observe how two different ionic compounds can be created from two ionic
compounds in solution.
MATERIALS

0.1M solution of sodium sulfide

Small funnel
(Na2S)

Filter paper
0.1M solution of copper(II)

Pipette
chloride (CuCl2)

20mL Measuring cylinder

3 micro test-tubes

2 Watch-glasses

Micro test tube rack

Hand lens or microscope

METHOD
1. Use the dropper to measure out 20 drops of the sodium sulfide solution and
pour this into a test-tube.
2. Measure out 20 drops of the copper(II) chloride solution and add it to a
different test-tube.
3. Create the insoluble compound copper(II) sulfide by pouring the sodium
sulfide into the test-tube with the copper(II) chloride solution.
4. Place the funnel into the third test-tube and add a fluted filer paper to it.
5. Separate the solid copper(II) sulfide from the liquid by pouring the mixture
through the filter paper.
6. Place the filter paper on a watch-glass, but open the paper up and leave it to
dry overnight.
7. Observe the copper(II) sulfide using your eyes, a hand lens or a microscope.
8. Pour some of the filtrate solution from the test-tube into a watch-glass and
leave it in a warm place to evaporate overnight. This should recrystallize as
an ionic solid.
9. Observe the crystals on the watch-glass, using the hand lens or a
microscope.
10. Observe the sodium sulfide and copper chloride as a solid under the hand
lens or microscope.
RESULTS
Observations
0.1M solution of sodium
sulfide
0.1M solution of copper(II)
chloride
Mixture of the two
solutions
Solid copper(II) sulfide
after filtration
Remaining solution after
filtration
Copper(II) sulfide after
drying
Recrystallised ionic
compound
Sodium sulfide as a
powder
Copper chloride as a
powder
Picture of material
DISCUSSION
1. List all the cations and anions involved in this experiment.
2.
a. Describe what happened when the two initial solutions were mixed.
b. Explain why this happened.
3. Deduce which ions went into making the solid in the filter paper and then write
its chemical formula.
4. Deduce which ions must have been left in solution after the solutions were
mixed.
5. Predict the chemical name and chemical formula of the recrystallised solid.
6. Propose whether the re-crystallised compound is pure or not. Use your
observations to support your answer.
CONCLUSION