Hydrolysis
of trans-Tetraamminedichlorocobalt(III) Chloride Hydrolysis
of trans-Tetraamminedichlorocobalt(III) Chloride
You may recall the cobalt compounds that were synthesized at the end of last semester. From that experiment, some knowledge about cobalt chemistry and the possible structures cobalt can form. In this lab, the cobalt complex that will be worked with is trans-Co(NH3)4Cl2. When this complex is put in water, the net reaction is that a water molecule will substitute in for a chlorine ion. Thus, the new compound that is formed is cis-Co(NH3)4(H20)Cl.
Since there is a change in the coordination of the cobalt complex, the
physical properties of the molecule will also change. The physical property
that is monitored in this experiment is the visible absorption spectra.
From the two absorption spectrum, you will learn how to choose a wavelength
to conduct analysis from and how to determine the rate constant for this
and similar reactions.
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General Procedure
Here is a simple over view of the procedure that will be used in this lab.
To
grind up the cobalt complex, a new piece of equipment will be used. The
agate mortar and pestle is a special type of mortar and pestle. It has
a an outer covering that resists adhesion of the ground up compound. Many
regular mortars and pestles have tiny imperfections that allows parts of
the compound to be pushed into those holes. The outer covering and special
material that the agate mortar and pestle has prevents this from occurring.
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