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Unformatted text preview: dence where the water has been "softened". Softening refers to a process whereby the
water is passed through a column in which the calcium and magnesium ions are removed.
This makes the water feel "softer" when taking a bath or shower, because the soap
precipitates do not form.
In this experiment, you will determine the amount of calcium carbonate present in an
unknown solid sample the stockroom has prepared. To do this you will use a hexadentate
ligand called ethylenediaminetetraacetic acid (EDTA). This ligand, due to its six donor
atoms and to its size and shape, has the exceptional ability to complex or chelate with a
variety of metal ions. The equilibrium constant for the formation of each metal/EDTA
complex is different, and the kinetic rate at which each metal complexing agent forms is
different as well. Thus, the ligand can be used to complex one metal ion in the presence
of another. For example, calcium-EDTA is given as an antidote for mercury ion
poisoning. Once the EDTA is ingested, it will selectively bind to...
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This note was uploaded on 04/09/2013 for the course CHE CHE 2C taught by Professor Nasiri during the Spring '07 term at UC Davis.
- Spring '07