Grade 8 Science Related Reading/ Materials
Grade 8
Materials
8M.3: Uses of Metals
Extraction of Metals
Task 1 - Pre- Reading Activity
Categorize the metals below into more reactive, less reactive or unreactive
Gold, Magnesium , Potassium , Copper , Calcium , Aluminum , Iron , Sodium , Zinc ,
Tin , Silver
Gold Gold
Calcium
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Grade 8 Science Related Reading/ Materials
Task 2 – Reading Activity
EXTRACTION OF METALS FROM THEIR ORES
Metals are very useful. Ores are naturally occurring rocks that contain metal or
metal compounds in sufficient amounts to make it worthwhile extracting them.
The method used to extract a given metal from its ore depends upon the
reactivity of the metal and so how stable the ore is. Very reactive metals are
Very
extracted using electricity, while less reactive metals are extracted by reduction
with
with carbon.
How reactive metals can
be extracted from their
ores?
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Methods of extracting metals
The method used to extract a metal from its ore depends upon the stability of its compound in
the ore, which in turn depends upon the reactivity of the metal:
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The oxides of very reactive metals, such as aluminium, form stable oxides and other compounds.
A lot of energy is needed to reduce them to extract the metal.
The oxides of less reactive metals, such as iron, form less stable oxides and other compounds.
Relatively little energy is needed to reduce them to extract the metal.
So, the method of extraction of a metal from its ore depends on the metal's position in the
reactivity series.
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Metal
Reactivity
potassium
sodium
calcium
magnesium
aluminium
extract by electrolysis
carbon
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zinc
iron
tin
lead
extract by reaction with carbon or carbon monoxide
hydrogen


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copper
silver
gold
platinum
extracted by various chemical reactions
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Grade 8 Science Related Reading/ Materials
Reactive metals such as aluminium are extracted by electrolysis, while a less-reactive metal
such as iron may be extracted by reduction with carbon. Gold, because it is so unreactive, is
found as the native metal and not as a compound, so it does not need to be chemically
separated. However, chemical reactions may be needed to remove other elements that might
contaminate the metal.
Is That a Banana in Water?
New science shows peels can remove heavy metals from water.
Anne Minard
For: National Geographic News
Published March 11, 2011
Banana peels are no longer just for composting or comedy shows: New science shows they
can pull heavy metal contamination from river water. Metals such as lead and copper are
introduced to waterways from a variety of sources, including agricultural runoff and industrial
wastes. Once there, heavy metals can contaminate soils and pose health risks to humans and
other species. Lead is known to affect the brain and nervous system.
Traditionally, water quality engineers have used silica, cellulose, and aluminum oxide to
extract heavy metals from water, but these remediation strategies come with high price tags
and potentially toxic side effects of their own. They work as extractors due to the presence of
acids which attract metal ions.
Bananas, on the other hand, appear to be a safe solution. Banana peels also outperform the
competition, says Gustavo Castro, a researcher at the Biosciences Institute at Botucatu, Brazil,
and a coauthor of a new study on this new use of the fruit’s peel.
For the study, Castro and his team dried and ground banana peels, then combined them in
flasks of water with known concentrations of metals. They also built water filters out of peels
and pushed water through them.
In both scenarios, “the metal was removed from the water and remained bonded to the
banana peels,” Castro said, adding that the extraction capacity of banana peels exceeded that
of other materials used to remove heavy metals.
Previous work has shown that other plant parts—including apple and sugar cane wastes,
coconut fibers, and peanut shells—can remove potential toxins from water.
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Grade 8 Science Related Reading/ Materials
Task 3 – Post Reading Activity
Q1: Why do we have different methods to extract the metals?
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Q2: What is meant by ore?
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Q3: What do reactivity series of metals show?
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Q4: How banana peels can extract heavy metals from water?
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Q5: Answer the following questions by the help of reactivity series:
1. Which metals more reactive than hydrogen but less reactive than carbon?
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2. Which cannot be extracted from its ore with carbon
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Grade 8 Science Related Reading/ Materials
3. Which is found in rocks as the metal itself?
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Q6: Choose the best answer:
1. When copper is extracted from copper oxide:
a. copper is oxidized
b. copper is reduced
c. copper oxide is oxidized
d. copper oxide is reduced
2. The most reactive metal out of potassium , aluminium , iron and zinc is:
a. aluminium
b. iron
c. zinc
d. potassium
3. Why is iron extracted from its ore by reduction using carbon?
a. Iron is more reactive than carbon.
b. Iron is less reactive than carbon.
c. Iron is less reactive than hydrogen.
d. Iron is more reactive than hydrogen
4. Why is aluminium extracted from its ore using electricity?
a. It is cheap and easy to do.
b. Aluminium is less reactive than hydrogen.
c. Aluminium is more reactive than carbon.
d. Aluminium is unreactive.
5. Which metal is most likely to be found in its native state in the Earth's crust?
a. potassium
b. platinum
c. iron
d. sodium
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