John Ogilvie High School
Chemistry Department
Curriculum for Excellence
Chemistry
Topic 7
The Earth’s Materials
Name:______________________________ Class: _______
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Curriculum for Excellence—Experiences and Outcomes
Science
Through evaluation of a range of data, I can describe the formation, characteristics and uses of
soils, minerals and basic types of rocks. SCN 3-17a
I can participate in practical activities to extract useful substances from natural resources.
SCN 3-17b
I have helped to design and carry out practical activities to develop my understanding of chemical
reactions involving the Earth's materials. I can explain how we apply knowledge of these
reactions in practical ways. SCN 3-19b
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The Earth
Crust
The Crust is the surface layer of the Earth. It is approximately 10km thick and it is
where humans and other life acquire all of their resources.
Mantle
The Mantle is found beneath the crust and is made up of a layer of very hot molten
rock called MAGMA.
Core
This layer is found at the very centre of the Earth and is made up of molten Iron.
The temperature of this layer is around 4000oC.
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Types of Rocks
Sedimentary
Sedimentary rocks are formed from particles of sand, shells, pebbles, and other
fragments of material. Together, all these particles are called sediment. Gradually,
the sediment accumulates in layers and over a long period of time hardens into rock.
Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You
can often see sand, pebbles, or stones in the rock, and it is usually the only type that
contains fossils.
Examples of this rock type include conglomerate and limestone.
Metamorphic
Metamorphic rocks are formed under the surface of the earth from the metamorphosis (change) that occurs due to intense heat and pressure (squeezing). The rocks
that result from these processes often have ribbonlike layers and may have shiny
crystals, formed by minerals growing slowly over time, on their surface.
Examples of this rock type include gneiss and marble.
Igneous
Igneous rocks are formed when magma (molten rock deep within the earth) cools and
hardens. Sometimes the magma cools inside the earth, and other times it erupts
onto the surface from volcanoes (in this case, it is called lava). When lava cools very
quickly, no crystals form and the rock looks shiny and glasslike. Sometimes gas bubbles are trapped in the rock during the cooling process, leaving tiny holes and spaces
in the rock.
Examples of this rock type include basalt and obsidian.
Your teacher will show you a Video called
“CfE Rocks Video 1”
Your teacher will show you a PowerPoint called
“Rocks”
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The Rock Cycle
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Metals from Rocks
Metals such as Gold and Silver can be dug straight from the ground as the solid
metal.
Gold Rushes were created at the early part of the 19th Century. A “Gold Rush” was
created as a result of finding some solid gold in the ground and causing miners and
workers to emigrate to the location of the Gold to begin removing it from the
ground. Many people were drawn to gold mines as a result of the wealth that could
be created from Gold.
Think about some of the uses for Gold and Silver and write them down:
You should be able to see that Gold and Silver are VERY UNREACTIVE.
For some metals it is harder to obtain them as they do not exist as pure metals.
They are found combined in the earth’s crust as compounds. The following
experiments will show you two different ways which metals can be extracted.
These compounds of metals are called METAL ORES.
Experiment 1—Extraction with Heat (DEMO)
1.
2.
3.
4.
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Add a spatula of Silver oxide into a boiling tube and clamp it facing the wall.
Roast the test tube in the blue flame of a Bunsen burner. Point the mouth of
the test tube to the wall.
Observe any changes.
Your teacher may test the gas produced at the mouth of the test tube with a
glowing splint.
Aim:
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Apparatus:
Method:
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Results:
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Conclusion:
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Experiment 2—Exteraction with Heat & Carbon
1.
2.
3.
4.
Add a spatula of copper (II) oxide into a micro test tube.
Add a spatula of powdered charcoal into the same test tube.
Mix the contents as best you can by tapping on the side of the tube.
Using metal tongs, roast the test tube in the blue flame of a Bunsen burner.
Point the mouth of the test tube to the wall.
5.
Lower the roasting hot test tube into a beaker
of cold water (WARNING—It will shatter).
Place the remaining test tube in the glass bin.
Now examine the bottom of the beaker.
6.
7.
Describe any of your observations
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Your teacher will show you a PowerPoint called
“Extraction of Copper 1”
Draw a diagram to illustrate what happens to the atoms of copper and oxygen
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Experiment 3—Extrating a metal using Electricity.
Some metals which are more reactive need a little more energy to extract them
from their ores. In this experiment we will show how metals can be extracted using
electricity. This method is called Electrolysis.
Using electricity
To split or break up
Electrolysis—To split or break up a compound by the passage of electricity.
Copper chloride
solution
1.
2.
3.
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Set up the apparatus as shown. (Your teacher will help you)
Follow the leads from the battery/power pack terminal to the electrode
and make a note of which electrode is positive and which is negative.
Turn on the power and write down your observations.
What did you see happening at the positive electrode?
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What did you see happening at the negative electrode?
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Your teacher will show you a PowerPoint called
“Electrolysis Demonstration”
Increasing reactivity
The method of metal extraction from their ores depends on how reactive the metal
is. The following table will help you identify how reactive a metal actually is.
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Police
Potassium
Sergeant
Sodium
Larry
Lithium
Charlie
Calcium
M
Magnesium
A
Aluminium
Z
Zinc
I
Iron
N
Nickel
T
Tin
L
Lead
HAS
HYDROGEN
Caught
Copper
Me
Mercury
Stealing
Silver
Gold
Gold
Extraction
by
Electrolysis
Extraction
by
Heat and Carbon
Extraction
by
Heat alone
Some uses for these metals
In our previous topics we described the differences between metals and non-metals.
Metals are well known conductors of electricity. However, it is also possible to use
metals to generate (create) electricity.
Experiment 4—Making a simple Electrochemical Cell
Your teacher will show you how to set up the following simple cell. You will be given a
variety of metals. Use various combinations and write down the voltage produced in
each case. (At time try and use the same metal for both A and B).
Metal A
Metal B
Voltage (V)
What happens if the filter paper is removed from the set-up?
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Look at the two metals used (and look at pg 7 of your data booklet). Can you stop a
trend.
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