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CEJ Vol. 7, No. 2, ContentsChemical Education Journal (CEJ), Vol. 7, No. 2 /Registration No. 7-15/Received October 10, 2003.
Gothenburg University, Department of Chemistry, SE-412 96 Gothenburg, Sweden
University of Halmstad, Section for Economics and Engineering, Box 823, SE-301 18 Halmstad, Sweden
Director of the Swedish Microscale Chemistry Center, Aprilv 14a, SE-302 40 Halmstad, Sweden
mail: gruvberg@kreativkemi.se
Summary:
Two experiments in sequence use the same salt for quantitative
measurements, one is using a gravimetric method and one is using
a colorimetric method. One is determining the number of crystal
water molecules in copper sulfate, one is determining the mole
concentration of the same salt in a solution that they have prepared
with high accuracy. The two experiments give use to a lot of the
theory in stoichiometrics that they have learnt during lectures
and in problem solving. The use of the same salt in both experiments
improves the value of the second experiment as this offers them
a situation where they can draw conclusions built on experiences
that they picked up in the first experiment. In order to get good
results they have practiced methods they can use in other occasions,
they have been trained to work with accuracy combined with awareness
of the benefit to do so. My experience is that the students are
engaged in these two experiments and they give feed back that
this sequence is effective in bringing understanding to their
studies.