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Cop fact-ite
G eo fac t s an d ac t i v i t i es f o r t h e c l ass room
Copper is a
metallic element
Properties
of copper
Elements are the building blocks
of our planet and copper is one
of 94 naturally occurring elements.
It is a metallic material with a
distinct red-orange colour and
metallic lustre. It’s Atomic Number
is 29, its Atomic Mass is 63.546
and its symbol is Cu.
Copper is essential to the
functioning of society and has
played several important roles in
society for thousands of years. It
is present in almost every modern
household item that uses electricity.
Copper is a soft, malleable and
ductile metal. This means it can
be beaten into thin sheets, can
be drawn out into thin wires and
made into pipes. Copper readily
form compounds and while it does
oxidise or tarnish it does not do so
as readily as other metals.
Copper is a relatively abundant element.
It is estimated copper atoms comprise 22
parts per million [ppm] of the Earth’s crust
making it the 8th most abundant metal.
This translates to 68 ppm by weight.
However, sometimes geological processes
concentrate copper into ore deposits
where it may be present in sulphide
minerals or secondary minerals that result
in copper yields of up to 1% of the host
rock minerals.
Copper is known from over 150 different
minerals but also occurs in its pure form
in the crust. It is sometimes found as
lumps of pure metal in sufficient amounts
to allow it to be beaten into objects with
no extra treatment. For this reason many
historians think copper was probably the
first metal utilised by people, resulting
in the development of more technical
civilizations.
Copper is a good conductor of heat and
electricity. It is a better conductor than
most metals. Silver is a better electrical
conductor but copper has better corrosion
resistance and is a more abundant and
hence cheaper material to use. Over half
the global copper production goes into
electrical wiring of some kind. Copper’s
heat conduction and corrosion resistance
properties also make it the metal of
choice for most vehicle radiators and
heat transfer units in refrigerators and air
conditioners.
Copper can also be joined to itself
very easily. This property, along with
its corrosion resistance, strength and
abundance has made copper the number
one material used in modern household
water piping and associated plumbing.
Copper is often alloyed with other
metals. Copper mixed with tin produces
an alloy called bronze. This material is
stronger and harder than copper and
today has many industrial uses but
historically the discovery of this alloy lead
to major changes in society through the
period we now call the bronze age.
Copper alloyed with zinc produces brass.
Brass is also stronger, harder and more
resistant to corrosion than copper and
today has major industrial applications
and uses in household equipment.
A gold-copper alloy called rose gold is a
popular metal for use in jewellery because
it retains the tarnish free qualities of gold
but is a harder more durable material than
pure gold. Copper is also a less expensive
material making rose gold a more cost
effective jewellery metal.
Australian coins are made from copper
alloys. ‘Silver’ coins are Cupro Nickel
(75% Copper, 25% Nickel) and ‘gold’
coins are Aluminium Bronze (92% Copper,
6% Aluminium, 2% Nickel).
The melting point of copper is ~1084oC
and it boils to a vapour at ~2562oC.
Copper is a dense material with a
specific gravity of 8.96.
Acknowledgement: Greg McNamara, Education and Outreach, Geological Society of Australia
http://www.gsa.org.au
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Copper chemistry
1. Copper atoms are present on Earth as two naturally
occurring isotopes; 63Cu [~70%] and 65Cu [~30%].
Given that copper has an Atomic Number of 29
how many protons, neutrons and electrons does
each isotope have?
2. Copper has two common oxidation states:
Cu+ and Cu 2+. Most copper compounds and
copper minerals form using these states.
The mineral cuprite has the formula Cu2O.
Is the copper present in this mineral
as Cu+ or Cu2+? Explain your answer
3. CuO is also an oxide of copper but is rarely found
in nature. What is the oxidation state of copper in
this compound?
4. Copper dissolves in hot sulphuric acid solution
and liberates a gas according to the formula:
Cu(s) + H2SO4(aq)
Cu2+(aq) + SO42-(aq) + H2(g)
What is the gas that is formed?
5. When copper sulphate forms it invariably
does so from aqueous solution and develops
a hydrated crystal according to the formula:
Cu2+(aq) + SO42-(aq)
CuSO4..5H20
In nature the water-soluble copper sulphate
pentahydrate compound occurs as the beautiful
blue mineral chalcanthite. It usually forms in the
oxidation zones associated with copper ore deposits.
However, it is not found at all mine sites. Is it more
likely to be found in the copper mines of arid inland
Australia or the copper mines of tropical central
America? Explain your answer.
6. The green copper carbonate hydroxide
mineral malachite has the formula Cu2CO3(OH)2.
It has a vibrant green colour and is often used
in jewellery.
What is the oxidation state of the copper given
that the hydroxide anion is [OH]-1 and the
carbonate anion is [CO3]-2 ?
Explain your reasoning.
7. The blue copper carbonate hydroxide
mineral azurite has the formula Cu3(CO3)2(OH)2.
It has a distinctive blue colour and was highly
prized as a paint pigment and jewellery mineral.
What is the oxidation state of copper in this mineral?
Explain your reasoning.
8. Copper roof sheets, copper guttering and pipes all
develop a distinctive green patina with age. Analysis
reveals the patina to be a thin layer of carbonate
material that has developed through weathering of
the metallic copper.
Is this carbonate more likely to be malachite or
azurite in composition? Explain your reasoning
9. Sulphide minerals such as chalcopyrite (CuFeS2),
bornite (Cu5FeS4), covellite (CuS)
and chalcocite(Cu2S) are all found in and
are major contributors to copper ores.
Draw up a table to chart the properties of these
4 copper sulphide minerals. Include the oxidation
state of the copper, the usual colour and lustre,
the hardness, the specific gravity, and the streak.
Also make notes about other interesting properties
of these minerals.
Acknowledgement: Greg McNamara, Education and Outreach, Geological Society of Australia
http://www.gsa.org.au