1. Core Chemistry Big Teach 2: Materials From the Earth

2. Key terms used in exam questions
Quarry– Where we dig limestone

3. Rocks Sedimentary Metamorphic Igneous Examples: Marble
Examples: Chalk and Limestone
How was it formed?
Sediments fall to bottom of the sea
Over millions of years
Layers compact
Rock formed
Things to know:
They contain fossils
They erode easily
Examples: Marble
How is it formed?
Sedimentary rocks are put under heat and pressure
Things to know
Limestone turns into Marble
The heat comes from the magma
Examples: Granite
How is it formed
When Lava cools
Things to Know
Marble turns into granite
If the laveacools quickly it contains small crystals
If it cools slowly It contains large crystals

7. The “Limestone Cycle”
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CO2
Calcium Carbonate
(limestone)
CO2
Step 4: add CO2
Step 1: heat
Calcium Hydroxide solution
Calcium Oxide
Step 3: add more water and filter
Step 2: add a little water
H2O
Calcium Hydroxide
H2O
H2O
H2O

8. Remember – They are all the same thing
Limestone
Calcium Carbonate
CaCO3

9. Remember – They are all the same thing
Limewater
Calcium Hydroxide
Ca(OH)2

10. Remember – The Test for carbon dioxide
Bubble the gas through limewater
Lime water goes cloudy

11. Calcium Carbonate – The neutraliser
Why is it sprayed onto fields
Neutralise acidic soil
Why is it sprayed onto waste gases from chimneys
Neutralise acidic waste gases
Why is it taken as an indigestion remedy
Neutralise excess acid in stomach

12. Limestone
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Limestone has a number of uses when it undergoes chemical reactions. There are two reactions to know:
1) Firstly, a THERMAL _________________ reaction is used to break the calcium carbonate down into calcium ______ and _______ __________:
2) _____ is then added to produce calcium __________:
Calcium carbonate calcium oxide + carbon dioxide
HEAT
Calcium oxide calcium hydroxide
WATER
Words – hydroxide, decomposition, carbon dioxide, water, oxide

18. Indicative Content
Mark
   
*(i)
A description including some of the following Step A heat limestone strong heat / with roaring Bunsen flame thermally decompose limestone to form calcium oxide and carbon dioxide allow to cool word eqn: calcium carbonate → calcium oxide + carbon dioxide bal eqn: CaCO3 → CaO + CO2 Step B add water to calcium oxide calcium oxide swells/cracks/steams until in excess white solid dissolves in water filter mixture to remove unreacted calcium hydroxide colourless solution formed word eqn: calcium oxide + water → calcium hydroxide bal eqn: CaO + H2O → Ca(OH)2
          (6)

19. After its use it can be turned into a lake Damages habitats
Advantages of a limestone quary
Disadvantages of a limestone quary
Social (people living in the local area)
 Provides jobs   
 Noisy
Dusty
Evironmental
 After its use it can be turned into a lake
 Damages habitats
Economic (money)
 Limestone is a valuable resource
 Loss of tourism

20. Limestone + sand + soda glass
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Limestone is a __________ rock made up of mainly calcium carbonate. It’s cheap and easy to obtain. Some uses:
1) Building materials – limestone can be quarried and cut into blocks to be used in _______. However, it is badly affected by ____ ____.
2) Glass making – glass is made by mixing limestone with _____ and soda:
Limestone + sand + soda glass
3) Cement making – limestone can be “roasted” in a rotary kiln to produce dry cement. It’s then mixed with sand and gravel to make _______.
Words – sand, building, sedimentary, concrete, acid rain

21. Uses of these Calcium compounds
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Calcium carbonate (limestone), calcium oxide and calcium hydroxide have a number of uses:
1) Neutralising acidic soil – calcium carbonate, calcium hydroxide and calcium oxide are _______ and can be used to ________ soil acidity to help ______ growth.
2) Removing pollutants – calcium carbonate can be used as a “_______” to remove acidic gases from a coal-fired power station’s waste products, helping prevent ____ _____.
Words – acid rain, alkaline, plant, scrubber, neutralise

23. An explanation including some of the following calcium carbonate/limestone · for buildings · making roads · treating acid soil/ treating acid lakes · in power station chimneys · making cement · making concrete and mortar · making glass · extracting iron · heating (to make calcium oxide) · making sodium carbonate · as a filler in plastics and paper · in paints · toothpaste · gravestones · statues, decorative stonework · indigestion remedies · railway ballast · bread making
calcium oxide · treating acid soil · in power station chimneys · making calcium hydroxide (when water added)calcium hydroxide · treating acid soil · making limewater