Description of experiment
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Needed compounds:
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cupric chloride dihydrate : CuCl2 . 2H2O
acetone : CH3 CO CH3
Class:
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elem=C,Cu
coordination
Summary:
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Anhydrous copper (II) chloride, when added to acetone, dissolves with a
yellow/brown/green color. When a saturated solution is allowed to stand for
several hours at 10 C or so, then red/brown crystals are formed. When the
crystals are heated, then they become dark brown and a flammable vapor is
produced (most likely acetone).
Probably, from a saturated solution of copper(II)chloride in acetone, an adduct
is formed of the form CuCl2.nCH3COCH3.
Description:
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Carefully heat some copper (II) chloride, dihydrate, until a dark brown solid
is obtained. Add some of this solid to acetone: Part of the solid dissolves,
the liquid becomes yellow/brown/green and clear. The part of the solid, which
does not dissolve settles at the bottom.
Swirl the test tube quite some time, in order to be sure that a saturated
solution is obtained. After this, decant the liquid from the not-dissolved
solid and let this liquid stand for one day: After one day, the liquid has
become much lighter (but still the same color) and red/brown crystals are
formed at the bottom. These crystals are needle-shaped and are fairly large (2
mm length, diameter a few tenths of mm). These crystals have a nice color and
their appearance resembles the appearance of metallic co
Decant the liquid from the red crystals and carefully press the crystals
between two filter papers in order to make them clean. Allow the crystals to
dry for a few minutes, until they do not smell of acetone anymore: Nice dry
crystals are obtained.
Carefully heat the crystals: The crystals become dark brown like chocolate. The
vapor, given off by the crystals, is flammable and can easily be ignited.
Add the dark brown solid, which remains after heating, to a fairly large amount
of water: The solid quickly dissolves and the solution becomes light blue and
clear.
Remark: CuCl2 dissolves in acetone as a covalent compound and most likely the
red/brown crystals are an adduct of CuCl2 and acetone.